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Cassini Finds that Titan is Building the Chemicals that Might Have Led to Life on Earth

universetoday - 2017. július 27. 22:00

Titan, Saturn’s largest moon, has been a source of mystery ever since scientists began studying it over a century ago. These mysteries have only deepened with the arrival of the Cassini-Huygens mission in the system back in 2004. In addition to finding evidence of a methane cycle, prebiotic conditions and organic chemistry, the Cassini-Huygens mission has also discovered that Titan may have the ingredient that help give rise to life.

Such is the argument made in a recent study by an international team of scientists. After examining data obtained by the Cassini space probe, they identified a negatively charged species of molecule in Titan’s atmosphere. Known as “carbon chain anions”, these molecules are thought to be building blocks for more complex molecules, which could played a key role in the emergence of life of Earth.

The study, titled “Carbon Chain Anions and the Growth of Complex Organic Molecules in Titan’s Ionosphere“, recently appeared in The Astrophysical Journal Letters. The team included researchers from University College in London, the University of Grenoble, Uppsalla University, UCL/Birkbeck, the University of Colorado, the Swedish Institute of Space Physics, the Southwest Research Institute (SwRI), and NASA’s Goddard Space Flight Center.

Diagram of the internal structure of Titan according to the fully differentiated dense-ocean model. Credit: Wikipedia Commons/Kelvinsong

As they indicate in their study, these molecules were detected by the Cassini Plasma Spectrometer (CAPS) as the probe flew through Titan’s upper atmosphere at an distance of 950 – 1300 km (590  – 808 mi) from the surface. They also show how the presence of these molecules was rather unexpected, and represent a considerable challenge to current theories about how Titan’s atmosphere works.

For some time, scientists have understood that within Titan’s ionosphere, nitrogen, carbon and hydrogen are subjected to sunlight and energetic particles from Saturn’s magnetosphere. This exposure drives a process where these elements are transformed into more complex prebiotic compounds, which then drift down towards the lower atmosphere and form a thick haze of organic aerosols that are thought to eventually reach the surface.

This has been the subject of much interest, since the process through which simple molecules form complex organic ones has remained something of a mystery to scientists. This could be coming to an end thanks to the detection of carbon chain anions, though their discovery was altogether unexpected. Since these molecules are highly reactive, they are not expected to last long in Titan’s atmosphere before combining with other materials.

However, the data showed that the carbon chains became depleted closer to the moon, while precursors to larger aerosol molecules underwent rapid growth. This suggests that there is a close relationship between the two, with the chains ‘seeding’ the larger molecules. Already, scientists have held that these molecules were an important part of the process that allowed for life to form on Earth, billions of years ago.

A halo of light surrounds Saturn’s moon Titan in this backlit picture, showing its atmosphere. Credit: NASA/JPL/Space Science Institute

However, their discovery on Titan could be an indication of how life begins to emerge throughout the Universe. As Dr. Ravi Desai, University College London and the lead author of the study, explained in an ESA press release:

“We have made the first unambiguous identification of carbon chain anions in a planet-like atmosphere, which we believe are a vital stepping-stone in the production line of growing bigger, and more complex organic molecules, such as the moon’s large haze particles. This is a known process in the interstellar medium, but now we’ve seen it in a completely different environment, meaning it could represent a universal process for producing complex organic molecules.”

Because of its dense nitrogen and methane atmosphere and the presence of some of the most complex chemistry in the Solar System, Titan is thought by many to be similar to Earth’s early atmosphere. Billions of years ago, before the emergence of microorganisms that allowed for subsequent build-up of oxygen, it is likely that Earth had a thick atmosphere composed of nitrogen, carbon dioxide and inert gases.

Therefore, Titan is often viewed as a sort planetary laboratory, where the chemical reactions that may have led to life on Earth could be studied. However, the prospect of finding a universal pathway towards the ingredients for life has implications that go far beyond Earth. In fact, astronomers could start looking for these same molecules on exoplanets, in an attempt to determine which could give rise to life.

This illustration shows Cassini above Saturn’s northern hemisphere prior to one of its 22 Grand Finale dives. Credit: NASA/JPL-Caltech

Closer to home, the findings could also be significant in the search for life in our own Solar System. “The question is, could it also be happening within other nitrogen-methane atmospheres like at Pluto or Triton, or at exoplanets with similar properties?” asked Desia. And Nicolas Altobelli, the Project Scientist for the Cassini-Huygens mission, added:

These inspiring results from Cassini show the importance of tracing the journey from small to large chemical species in order to understand how complex organic molecules are produced in an early Earth-like atmosphere. While we haven’t detected life itself, finding complex organics not just at Titan, but also in comets and throughout the interstellar medium, we are certainly coming close to finding its precursors.

Cassini’s “Grande Finale“, the culmination of its 13-year mission around Saturn and its system of moons, is set to end on September 15th, 2017. In fact, as of the penning of this article, the mission will end in about 1 month, 18 days, 16 hours, and 10 minutes. After making its final pass between Saturn’s rings, the probe will be de-orbited into Saturn’s atmosphere to prevent contamination of the system’s moons.

However, future missions like the James Webb Space Telescope, the ESA’s PLATO mission and ground-based telescopes like ALMA are expected to make some significant exoplanet finds in the coming years. Knowing specifically what kinds of molecules are intrinsic in converting common elements into organic molecules will certainly help narrow down the search for habitable (or even inhabited) planets!

Further Reading: ESA, The Astrophysical Journal Letters

The post Cassini Finds that Titan is Building the Chemicals that Might Have Led to Life on Earth appeared first on Universe Today.

Milky Way's origins are not what they seem

sciencedaily.com - 2017. július 27. 20:18
Up to half of the matter in our Milky Way galaxy may come from distant galaxies, astrophysicists have discovered in a first-of-its-kind analysis. As a result, each one of us may be made in part from extragalactic matter. Using supercomputer simulations, the researchers found an unexpected mode for how galaxies acquired matter: intergalactic transfer. Supernova explosions eject copious amounts of gas from galaxies, causing atoms to be transported from one galaxy to another via powerful galactic winds.

Hubble Sees Tiny Phobos Orbiting Mars

universetoday - 2017. július 27. 20:14

Mars’ moon Phobos is a pretty fascinating customer! Compared to Mars other moon Deimos, Phobos (named after the Greek personification of fear) is the larger and innermost satellite of the Red Planet. Due to its rapid orbital speed, the irregularly-shaped moon orbits Mars once every 7 hours, 39 minutes, and 12 seconds. In other words, it completes over three orbits of Mar within a single Earth day.

It’s not too surprising then that during a recent observation of Mars with the Hubble space telescope,  Phobos chose to photobomb the picture! It all took place in May of 2016, when while Mars was near opposition and Hubble was trained on the Red Planet to take advantage of it making its closest pass to Earth in over a decade. The well-timed sighting also led to the creation of a time-lapse video that shows the moon’s orbital path.

During an opposition, Mars and Earth are at the closest points in their respective orbits to each other. Because Mars and the Sun appear to be on directly opposite sides of Earth, the term “opposition” is used. These occur every 26 months, and once every 15 to 17 years, an opposition will coincide with Mars being at the closest point in its orbit to the Sun (perihelion).

Phobos from NASA’s Mars Reconnaissance Orbiter on March 23, 2008. Credit: NASA

When this happens, Mars is especially close to Earth, which makes it an ideal occasion to photograph it. The last time this occurred was on May 22nd, 2016, when Mars was and Earth were at a distance of about 76,309,874 km (47,416,757 mi or 0.5101 AU) from each other. This would place it closer to Earth than it had been in 11 years, and the Hubble space telescope was trained on Mars to take advantage of this.

A few days before Mars made its closest pass, Hubble took 13 separate exposures of the planet over the course of 22 minutes, allowing astronomers to create a time-lapse video. This worked out well, since Phobos came into view during the exposures, which led the video showing the path of the moon’s orbit. Because of its small size, Phobos looked like a star that was popping out from behind the planet.

This sighting has only served to enhance Phobos’ fascinating nature. As of 2017, astronomers have been aware of the moon’s existence for 140 years. It was discovered in 1877, when Asaph Hall – while searching for Martian moons – observed it from the U.S. Naval Observatory in Washington D.C. A few days later, he also discovered Deimos, the smaller, outer moon of Mars.

In July of 1969, just two weeks before the Apollo landing, the Mariner 7 probe conducted a flyby of Mars and took the first close-up images of the Moon. In 1977, a year after the Viking 1 lander was deployed to the Martian surface, NASA’s Viking 1 orbiter took the first detailed photographs of the moon. These revealed a cratered surface marred by long, shallow grooves and one massive crater – known as the Stickney crater.

The streaked and stained surface of Phobos, with a close-up on the Stickney crater. Credit: NASA

Asaph Hall named this crater after Chloe Angeline Stickney Hall (his wife) after discovering it in 1878, a year after he discovered Phobos and Deimos. Measuring some 10 km in diameter – almost half of the average diameter of Phobos itself – the impact that created Stickney is believed to have been so powerful that it nearly shattered the moon.

The most widely-accepted theory about Phobos origins is that both it and Deimos were once asteroids that were kicked out of the Main Belt by Jupiter’s gravity, and were then acquired by Mars. But unlike Deimos, Phobos’ orbit is unstable. Every century, the moon draws closer to Mars by about 1.98 meters (6.5 feet). At this rate, scientist estimate that within 30 to 50 million years, it will crash into Mars or be torn to pieces to form a ring in orbit.

This viewing is perhaps a reminder that this satellite won’t be with Mars forever. Then again, it will certainly still be there if and when astronauts (and maybe even colonists) begin setting foot on the planet. To these people, looking up at the sky from the surface of Mars, Phobos will be seen regularly eclipsing the Sun. Because of its small size, it does not fully eclipse the Sun, but it does make transits multiple times in a single day.

So there’s still plenty of time to study and enjoy this fearfully-named moon. And while you’re at it, be sure to check out the video below, courtesy of NASA’s Goddard Space Center!

Further Reading: HubbleSite, NASA

The post Hubble Sees Tiny Phobos Orbiting Mars appeared first on Universe Today.

Milky Way May Be Made with Swapped Gas

skyandtelescope.com-MostRecent - 2017. július 27. 18:34

High-powered simulations suggest that half of the material in the Milky Way could come from other galaxies.

The barred spiral NGC 4911, surrounded by galactic friends in the Coma Cluster. Simulations suggest that galaxies trade a large fraction of their gas with one another via star-driven gas outflows.
NASA / ESA / Hubble Heritage Team (STScI / AURA)

Galaxies might look like pristine “island universes,” exchanging stars and gas only when they crash into each other. But real life is messier. Stellar winds and supernovae blow huge amounts of gas out of their host galaxies, some of which rains back down. If launched well enough, though, the gas can escape permanently into intergalactic space, where it may be caught up by other galaxies.

Using the high-definition FIRE simulations, Daniel Anglés-Alcázar (Northwestern University) and colleagues took a closer look at these well-known processes. The team watched the development over cosmic time of multiple systems of galaxies, each with a different kind of galaxy in the middle. FIRE’s superb resolution enabled the team to track gas particles as they flowed here and there in these systems, moving out of, and back into, individual galaxies and between the central galaxy and the ones surrounding it.

Reporting in the October 2017 Monthly Notices of the Royal Astronomical Society, the team found that galaxies are picking up a lot more stuff from other galaxies than previous thought. Previous work had suggested very little of the gas in a Milky Way–mass galaxy would come from other galaxies, maybe 10-20%. FIRE’s numbers are much higher: Somewhere between 20% and 60% of the gas in a modern Milky Way is “intergalactic” — stuff blown out of one galaxy and nabbed by another.

In today’s universe, the team finds, the exchange of gas between galaxies via galactic winds can even be the dominate way a big galaxy acquires material, outstripping in importance the accretion of fresh, unprocessed gas or the recycling of the galaxy’s own outflows. (The latter are more important for dwarf galaxies.)

The simulations also suggest that a Milky Way galaxy permanently chucks out a ton of gas, equivalent to the mass of all the galaxy’s stars — for our galaxy, that’s in the range of 100 billion Suns.

The new result might cause an interesting complication. Astronomers study the history of a galaxy’s different structures and stellar populations using the stars’ compositions: A higher fraction of heavy elements, or metals, generally means the stars formed from gas that’s already been processed by previous generations of stars. But if galaxies are swapping gas, does that undermine astronomers’ study of what’s happening within a galaxy and how it has grown?

Unclear, but probably not. On one hand, intergalactic transfer isn’t as important when a galaxy is first pulling itself together and building things like a spiral disk and central bulge. Plus the metal enrichment that gas undergoes within a galaxy may be far more marked than what it would retain from a previous galactic host. On the other hand, intergalactic transfer or same-galaxy recycling might leave some kind of metallicity fingerprint. If so, the imprint could provide an observational test for these simulations.

 

Reference: D. Anglés-Alcázar et al. “The Cosmic Baryon Cycle and Galaxy Mass Assembly in the FIRE Simulations.” Monthly Notices of the Royal Astronomical Society. October 2017.

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The post Milky Way May Be Made with Swapped Gas appeared first on Sky & Telescope.

Breakthrough Starshot Takes to Space

skyandtelescope.com-MostRecent - 2017. július 27. 18:15

Six Sprites, "the world's smallest spacecraft," have entered low-Earth orbit, a small milestone for Breakthrough Starshot's plan for interstellar voyage.

An artist's conception of a Breakthrough Starshot spacecraft in action.
Breakthrough Initiatives

“Space is big,” reads a line from Douglas Adams's Hitchhiker's Guide to the Galaxy. “REALLY big.” So big, one wonders if a spacecraft could ever reach even the nearest star system, Alpha Centauri.

One plan named Breakthrough Starshot wants to bridge that gulf to the nearest star within the century. Now, just a little over a year after the plan was announced, the initiative has achieved a small first, as a number of its small Sprite prototype spacecraft piggybacked into low-Earth orbit.

The idea behind Breakthrough Starshot is simple: accelerate a gram-scale spacecraft to 20% the speed of light (that's about 37,000 miles per second, fast enough to reach the Moon in less than 7 seconds) using ground-based lasers for the first interstellar mission. Yuri Milner announced the Breakthrough Starshot project as part of the larger Breakthrough Initiatives program in April 2016.

The $100 million of funding is a drop in the bucket compared to what a full interstellar mission would cost — it's basically a starter grant to fund research toward a proof of concept, to demonstrate that a tiny spacecraft could be accelerated to a fraction of the speed of light.

What the most recent test accomplished was a tiny but important milestone. Six postage-stamp-sized spacecraft, named Sprites, made it to orbit as supplementary payloads. Two are mounted on the larger Venta and Max Valier educational satellites built by European space company OHB System AG. Another four of the Sprites are still inside the Max Valier and awaiting deployment as independent spacecraft. The satellites launched aboard Polar Satellite Launch Vehicle from Satish Dhawan Space Center in southeast India on June 23, 2017.

A Sprite spacecraft.
Breakthrough Initiatives

From Sprites to Starchips

Each Sprite is built as a single circuit board 3.5 centimeters on a side and weighing just 4 grams (for comparison, a U.S. nickel weighs 5 grams). The femtocraft contain solar cells (which generate all of 100 milliWatts of power in direct sunlight), a magnetometer, gyroscope, and an antenna to communicate with Earth.

Both of the larger satellites have achieved stable orbits, but while ground stations in California and New York as well as amateur radio operators have detected Sprite signals, the team hasn't determined yet that they've detected two separate signals. Thus far, the Max Valier satellite is itself having trouble communicating, halting the release of the four Sprites still carried in its cargo container.

The ideas behind Breakthrough Starshot aren't without their own challenges, as the team readily acknowledges, but the scientists involved maintain that there aren't any dealbreakers.

Solar sail propulsion, long a staple of science fiction, is attractive in that the spacecraft wouldn't need to carry its own fuel. More fuel means more mass, which then means more fuel and, well, you get the idea. Robert Forward proposed the microwave-propelled Star Wisp mission in 1985, though it never took off. The Planetary Society lost its first solar sail mission in 2005, when its submarine-launched Cosmos-1 failed to reach orbit. Japan's Ikaros spacecraft finally became the first successful solar sail mission to fly in space, hitching a ride with the Venus-bound Akatsuki mission launched in 2010.

The IKAROS solar sail unfurled in solar orbit and imaged by one of its free flying DCAM cameras.
JAXA

Once accelerated to high speeds, more challenges face the spacecraft. How would it avoid dust particles when it's zipping along that fast? A tiny grain of dust, though rare in the space between stars, would pack a mission-ending punch when a spacecraft is moving at 20% the speed of light. Then there's the issue of braking on the other end — at least on the first try, we may have to settle for a brief 1- or 2-day flyby of the Alpha Centauri system after a 20 year long trip.

There's also the issue of communication. For example, New Horizons used a 2.1-meter dish to talk to Earth after its flight past Pluto and Charon in July 2015, and the distance reduced its data rate to that of a bad dial-up connection, at 1 kilobit (125 bytes) per second. Enabling something the size of a penny to talk to Earth from 4 light-years away is a non-trivial issue that the Breakthrough Starshot team will need to address.

We can always hope that Moore's Law holds true and computing power will continue to double every 18 months. Breakthrough Starshot's vision anticipates this, as well as the continued miniaturization of technology and solutions to current technical challenges. Hey, we have to at least try as a species if we ever want to reach the stars, right?

The post Breakthrough Starshot Takes to Space appeared first on Sky & Telescope.

Solar eclipse science along the path of totality

sciencedaily.com - 2017. július 27. 17:56
A number of research projects will take place across the country during the upcoming Aug. 21 solar eclipse. The research will advance our knowledge of the sun's complex and mysterious magnetic field and its effects on Earth's atmosphere and land.

New Comet: C/2017 O1 ASAS-SN Takes Earth by Surprise

universetoday - 2017. július 27. 17:00

Getting brighter… Comet O1 ASAS-SN from July 23rd. Image credit and copyright: iTelescope/Rolando Ligustri.

A new comet discovery crept up on us this past weekend, one that should be visible for northern hemisphere observers soon.

We’re talking about Comet C/2017 O1 ASAS-SN, a long period comet currently visiting the inner solar system. When it was discovered on July 19th, 2017 by the All Sky Automated Survey for Supernovae (ASAS-SN) system, Comet O1 ASAS-SN was at a faint magnitude +15.3 in the constellation Cetus. In just a few short days, however, the comet jumped up a hundred-fold in brightness to magnitude +10, and should be in range of binoculars now. Hopes are up that the comet will top out around magnitude +8 or so in October, as it transitions from the southern to northern hemisphere.

ASAS-SN North on the hunt. Credit: ASAS-SN

Never heard of ASAS-SN? It’s an automated sky survey hunting for supernovae in both hemispheres, with instruments based at Haleakala in Hawaii and Cerro Tololo in Chile. Though the survey targets supernovae, it does on occasion pick up other interesting astronomical phenomena as well. This is the first comet discovery for the ASAS-SN team, as they join the ranks of PanSTARRS, LINEAR and other prolific robotic comet hunters.

Evoking the very name “ASAS-SN” seems to have sparked a minor controversy as well, as the International Astronomical Union (IAU) declined to name the comet after the survey, listing it simply as “C/2017 O1”. Word is, “ASAS-SN” was to close to the word “Assassin” (this is actually controversial?) For our money, we’ll simply keep referring to the comet as “O1 ASAS-SN” as a recognition of the team’s hard work and their terrific discovery.

The orbit of Comet C/2017 O1 ASAS-Sn through the inner solar system. Credit: NASA/JPL

But what’s in a name, and does an interplanetary iceball really care? On a long term parabolic orbit probably measured in the millions of years, O1 ASAS-SN has an orbit inclined 40 degrees to the ecliptic, and reaches perihelion 1.5 AU from the Sun just outside the orbit of Mars on October 14th. This is most likely Comet C/2017 O1 ASAS-SN’s first passage through the inner solar system.

Currently located in the constellation Eridanus, hopefully comet O1 ASAS-SN’s current outburst holds. Expect it to climb northward through Taurus and Perseus over the next few months as it begins the long climb towards the north celestial pole.

Anatomy of an outburst: Comet ASAS-SN shortly after discovery over the span of a week. Credit ASAS-SN1.

As seen from latitude 30 degrees north, the comet will move almost parallel to the eastern horizon, and clears about 20 degrees altitude around local midnight, very well placed for northern hemisphere observers.

The path of Comet C/2017 O1 ASAS-SN parallel to the eastern horizon through September as seen from latitude 30 degrees north. Credit: Stellarium

At its closest in mid-October, Comet O1 ASAS-SN will be moving a degree a day through the constellation Camelopardalis

Here’s a month-by-month blow by blow for Comet O1 ASAS-SN:

August

14- Crosses into Cetus.

16- Crosses the celestial equator northward.

20- Crosses into Taurus.

The celestial path of Comet C/2017 O1 ASAS-SN from late July through mid-October (click to enlarge). Credit: Starry Night.

September

11-The waning gibbous Moon passes two degrees to the south.

17- Crosses the ecliptic northward.

20- Photo op: passes 4 degrees from the Pleiades open star cluster (M45).

28-Crosses into Perseus.

The projected light curve for Comet C/2017 O1 ASAS-SN. Note the outburst from actual observations (black dots). Credit: Seiichi Yoshida’s Weekly Information About Bright Comets.

October

1-Reaches max brightness?

12-Crosses the galactic equator northward.

14-Reaches perihelion 1.5 AU from the Sun.

17-Crosses into Camelopardalis.

18- Passes closest to Earth at 0.722 AU distant.

29-Passes 10′ from the +4 mag star Alpha Camelopardalis.

November

17-Crosses into Cepheus

December

6-Passes 3 degrees from the north celestial pole.

12-Reaches opposition.

31-Drops back down below +10th magnitude

At the eyepiece, a small comet generally looks like a small fuzzy globular cluster that refuses to snap into focus. Seek out dark skies in your cometary quest, as the least bit of light pollution will dim it below visibility. And speaking of which, the Moon is also moving towards Full next week so the time to hunt for the comet is now.

We’ve still got a few weeks left before the August 21st total solar eclipse for a bright “eclipse comet” to show up… unlikely, but it has happened once in 1948.

Comet C/2017 O1 ASAS-SN from July 23rd. Credit: Remanzacco Observatory.

Keep in mind, current magnitude estimates for Comet O1 ASAS-SN are still highly speculative, as we seem to have caught this one in outburst… hey, remember Comet Holmes back about a decade ago in 2007? One can only dream!

-Also check out this recent NEOWISE study suggesting that large long period comets may be more common that generally thought.

The post New Comet: C/2017 O1 ASAS-SN Takes Earth by Surprise appeared first on Universe Today.

Galactic David and Goliath

sciencedaily.com - 2017. július 27. 16:30
The gravitational dance between two galaxies in our local neighbourhood has led to intriguing visual features in both as witnessed in this new NASA/ESA Hubble Space Telescope image. The tiny NGC 1510 and its colossal neighbour NGC 1512 are at the beginning of a lengthy merger, a crucial process in galaxy evolution. Despite its diminutive size, NGC 1510 has had a significant effect on NGC 1512's structure and amount of star formation.

ALMA Captures Star Formation in Action

skyandtelescope.com-MostRecent - 2017. július 27. 15:00

New ALMA observations reveal a forming star as it launches a wind from the edge of the disk that feeds it.

Visible light shows the Barnard 59 region within the Pipe Nebula. While visible light cannot penetrate the thick cloud, radio waves can.
ESO

A Sun-like star is forming about 500 light-years from Earth: BHB07-11 is the youngest of a newborn cluster of stars coming together deep within the Pipe Nebula in Ophiuchus. The protostars in this cluster have collapsed out of the larger gas cloud, but they haven't ignited fusion just yet — they're still growing, feeding from the dusty disks surrounding them.

Now, new observations from the Atacama Large Millimeter/submillimeter Array (ALMA) have revealed BHB07-11 and its disk in exquisite detail that's enabling astronomers to answer questions about how stars form. (The full text announcing the results is available on the arXiv.)

One aspect that has long been difficult to understand is how collapsing gas loses its initial (random) spin. The gas within stars' natal clouds wants to preserve its angular momentum. So for the gas to actually collapse into a star, it first has to lose its spin — generally, that means that material actually has to leave the protostar, in the form of jets and winds, for other material to collapse inward. It's easy to think of a growing star as a toddler at the dinner table, where as much food goes on the floor as in their stomachs.

The ALMA observations of BHB07-11 show exactly that process in action — although unlike a toddler, this star has magnetic fields to contend with as well. The observations were taken at four sets of wavelengths. The first, at a wavelength of 1.3 millimeters, captures what little heat is emitted from cool dust. The 1.3-millimeter image reveals the dusty disk that's feeding the star, which extends to 80 a.u., about twice as far from the star as Pluto is from the Sun.

ALMA's 1.3-millimeter radio image reveals the emission from dust around the protostar BHB07-11. The dense central disk is surrounded by a sparser, spiral-shaped envelope of dust.
MPE

The other three sets of wavebands capture emission from certain molecules (namely, two isotopes of carbon monoxide and one of formaldehyde), which trace gaseous activity in the disk. Those images show that at the very edge of the disk, between 90 and 130 a.u. from the star, magnetic and centrifugal forces are combining to launch a lopsided wind. The launch point is right where material from the larger gas cloud falls onto the disk.

Observations of carbon monoxide emission (white contours) are shown on top of the dust emission. The emission is slightly shifted to longer or shorter wavelengths depending on the velocity of the material relative to the observer. Therefore, the panel on the left shows material moving towards us, while the right panel shows motion away from us. The wind is being launched from the very edge of the disk.
MPE

The magnetocentrifugal force has long been thought to power outflows from young stellar disks. However, while the classical picture has the magnetic field pinching into an hourglass shape within the disk (pictured here), the ALMA observations of BHB07-11 show that the pinching action may actually occur at or just outside the disk's edge.
Sheikhnezami et al., Astrophysical Journal

"Bipolar outflows powered from disks are common features in young stars," says Felipe Alves (Max Planck Institute for Extraterrestrial Physics, Germany), "but our work shows that a significant fraction of this outflow is probably powered at the disk external edge."

What's happening is that gas falling inward, onto the disk and toward the star, drags magnetic field lines with it. That action pinches the magnetic field, so that the field lines take on an hourglass shape. Gas within the disk continues to fall inward, but any gas particles slightly above or below the disk will feel a centrifugal force that shoots them away along the magnetic field lines.

These ALMA observations are the first to pinpoint the exact launch point, where the so-called magnetocentrifugal force powers this young star's outflow, to a location at the very edge of the star's disk.

 

The post ALMA Captures Star Formation in Action appeared first on Sky & Telescope.

A tale of three stellar cities: Three different populations of baby stars

sciencedaily.com - 2017. július 27. 14:31
Using new observations from ESO's VLT Survey Telescope, astronomers have discovered three different populations of baby stars within the Orion Nebula Cluster. This unexpected discovery adds very valuable new insights for the understanding of how such clusters form. It suggests that star formation might proceeds in bursts, where each burst occurs on a much faster time-scale than previously thought.

~Extreme UV Radiation~ on Partly Cloud Days - Heads-Up and Thanks TEAM UV!

napkitores.hu - 2017. július 27. 10:30
July 26, 2017: Relevant data you need to know...Be safe out there. **Outdoor Ultra Violet Sunlight is trending higher on partly cloudy days we are learning** Use ...

SpaceX has a Roomba-like robot but no one knows what it really is

napkitores.hu - 2017. július 27. 10:30
SpaceX fans are extremely curious about a new robot that keeps appearing on SpaceXs drone ship Of Course I Still Love You. Some are calling it the ...

Ufo észlelés Batley-ben

napkitores.hu - 2017. július 27. 10:30
Ufo észlelés Angliaban Barley-ben.

Breakthrough Lofts the Smallest Satellites Ever, not Interstellar Yet, but a Step Forward

universetoday - 2017. július 27. 00:19

In 2015, Russian billionaire Yuri Milner established Breakthrough Initiatives, a non-profit organization dedicated to enhancing the search for extraterrestrial intelligence (SETI). In April of the following year, he and the organization be founded announced the creation of Breakthrough Starshot, a program to create a lightsail-driven “wafercraft” that would make the journey to the nearest star system – Alpha Centauri – within our lifetime.

This past June, the organization took a major step towards achieving this goal. After hitching a ride on some satellites being deployed to Low Earth Orbit (LEO), Breakthrough conducted a successful test flight of its first spacecraft. Known as “Sprites”, these are not only the smallest spacecraft ever launched, but prototypes for the eventual wafercraft Starshot hopes to send to Alpha Centauri.

The concept for a wafercraft is simple. By leveraging recent developments in computing and miniaturization, spacecraft that are the size of a credit card could be created. These would be capable of carrying all the necessary sensors, microprocessors and microthrusters, but would be so small and light that it would take much less energy to accelerate them to relativistic speeds – in the case of Starshot, up to 20% the speed of light.

Artist’s illustration of a light-sail powered by a laser beam (red) generated on Earth’s surface. Credit: M. Weiss/CfA

As Pete Worden – Breakthrough Starshot’s executive director and the former director of NASA’s Ames Research Center – said in an interview with Scientific American:

“This is a very early version of what we would send to interstellar distances. In addition, this is another clear demonstration that it is possible for countries to work together to do great things in space. These are European spacecraft with U.S. nanosatellite payloads launching on an Indian booster—you can’t get much more international than that.”

Professor Abraham Loeb also has some choice words to mark this historic occasion. In addition to being the Frank B. Baird Jr. Professor of Science, the Chair of the Astronomy Department and the Director of the Institute for Theory and Computation at Harvard University, Prof. Loeb is also the chairman of the Breakthrough Starshot Advisory Committee. As he told Universe Today via email:

“The launch of the Sprite satellites marks the first demonstration that miniaturized electronics on small chips can be launched without damage, survive the harsh environment of space and communicate successfully with earth. The Starshot Initiative aims to launch similar chips attached to a lightweight sail that it being pushed by a laser beam to a fifth of the speed of light, so that its camera, communication and navigation devices (whose total weight is of order a gram) will reach the nearest planet outside the solar System within our generation.”

A prototype Sprite nanosatellite, showing its solar panel, microprocessors, sensors and transmitters. Credit: Zac Manchester

The craft were deployed on June 23rd, piggybacking on two satellites belonging to the multinational technology corporation OHB System AG. Much like the StarChips that Starshot is proposing, the Sprites represent a major step in the evolution of miniature spacecraft that can do the job of larger robotic explorers. They measure just 3.5 by 3.5 cm (1.378 x 1.378 inches) and weight only four grams (0.14 ounces), but still manage to pack solar panels, computers, sensors and radios into their tiny frames.

The Sprite were originally conceived by Zac Manchester, a postdoctorate researcher and aerospace engineer at Cornell University. Back in 2011, he launched a Kickstarter campaign (called “KickSat“) to raise funds to develop the concept, which was his way of bringing down the associated costs of spaceflight. The campaign was a huge success, with Manchester raising a total of $74,586 of his original goal of $30,000.

Now a member of Breakthrough Starshot (where he is in charge of Wafer design and optimization), Manchester oversaw the construction of the Sprites from the Sibley School of Mechanical and Aerospace Engineering at Cornell. As Professor Loeb explained:

“The Sprites project is led by Zac Manchester, a Harvard postdoc who started working on this during his PhD at Cornell. Sprites are chip-size satellites powered by sunlight, intended to be released in space to demonstrate a new technology of lightweight (gram-scale) spacecrafts that can communicated with Earth.”

Zac Manchester holding a prototype KickSat. Credit: Zac Manchester/kickstarer

The purpose of this mission was to test how well the Sprites’ electronics systems and radio communications performed in orbit. Upon deployment, the Sprites remained attached to these satellites (known as “Max Valier” and “Venta”) and began transmitting. Communications were then received from ground stations, which demonstrated that the Sprites’ novel radio communication architecture performed exactly as it was designed to.

With this test complete, Starshot now has confirmation that a waferocraft is capable of operating in space and communicating with ground-based controllers. In the coming months and years, the many scientists and engineers that are behind this program will no doubt seek to test other essential systems (such as the craft’s microthrusters and imagers) while also working on the various engineering concerns that an instellar mission would entail.

In the meantime, the Sprites are still transmitting and are in radio contact with ground stations located in California and New York (as well as radio enthusiasts around the world). For those looking to listen in on their communications, Prof. Loeb was kind enough to let us know what frequency they are transmitting on.

“The radio frequency at which the Sprites that were just launched operate is 437.24 MHz, corresponding to a wavelength of roughly 69 cm,” he said. So if you’ve got a ham radio and feel like tuning in, this is where to set your dials!

And be sure to check out Zac Manchester’s Kickstarter video, which showcases the technology and inspiration for the KickSat:

https://ksr-video.imgix.net/projects/50584/video-56971-h264_high.mp4

Further: Breakthrough Initiatives

The post Breakthrough Lofts the Smallest Satellites Ever, not Interstellar Yet, but a Step Forward appeared first on Universe Today.

Ready to Leave Low Earth Orbit? Prototype Construction Begins for a Deep Space Habitat

universetoday - 2017. július 26. 21:01

In 2010, NASA accounted its commitment to mount a crewed mission to Mars by the third decade of the 21st century. Towards this end, they have working hard to create the necessary technologies – such as the Space Launch System (SLS) rocket and the Orion spacecraft. At the same time, they have partnered with the private sector to develop the necessary components and expertise needed to get crews beyond Earth and the Moon.

To this end, NASA recently awarded a Phase II contract to Lockheed Martin to create a new space habitat that will build on the lessons learned from the International Space Station (ISS). Known as the Deep Space Gateway, this habitat will serve as a spaceport in lunar orbit that will facilitate exploration near the Moon and assist in longer-duration missions that take us far from Earth.

The contract was awarded as part of the Next Space Technologies for Exploration Partnership (NextSTEP) program, which NASA launched in 2014. In April of 2016, as part of the second NextSTEP Broad Agency Announcement (NextSTEP-2) NASA selected six U.S. companies to begin building full-sized ground prototypes and concepts for this deep space habitat.

Artist’s impression of the Deep Space Gateway, currently under development by Lockheed Martin. Credit: NASA

Alongside such well-known companies like Bigelow Aerospace, Orbital ATK and Sierra Nevada, Lockheed Martin was charged with investigating habitat designs that would enhance missions in space near the Moon, and also serve as a proving ground for missions to Mars. Intrinsic to this is the creation of something that can take effectively integrate with SLS and the Orion capsule.

In accordance with NASA’s specifications on what constitutes an effective habitat, the design of the Deep Space Gateway must include a pressurized crew module, docking capability, environmental control and life support systems (ECLSS), logistics management, radiation mitigation and monitoring, fire safety technologies, and crew health capabilities.

The design specifications for the Deep Space Gateway also include a power bus, a small habitat to extend crew time, and logistics modules that would be intended for scientific research. The propulsion system on the gateway would rely on high-power electric propulsion to maintain its orbit, and to transfer the station to different orbits in the vicinity of the Moon when required.

With a Phase II contract now in hand, Lockheed Martin will be refining the design concept they developed for Phase I. This will include building a full-scale prototype at the Space Station Processing Facility at NASA’s Kennedy Space Center at Cape Canaveral, Florida, as well as the creation of a next-generation Deep Space Avionics Integration Lab near the Johnson Space Center in Houston.

Artist’s concept of space habitat operating beyond Earth and the Moon. Credit: NASA

As Bill Pratt, Lockheed Martin’s NextSTEP program manager, said in a recent press statement:

“It is easy to take things for granted when you are living at home, but the recently selected astronauts will face unique challenges. Something as simple as calling your family is completely different when you are outside of low Earth orbit. While building this habitat, we have to operate in a different mindset that’s more akin to long trips to Mars to ensure we keep them safe, healthy and productive.”

The full-scale prototype will essentially be a refurbished Donatello Multi-Purpose Logistics Module (MPLM), which was one of three large modules that was flown in the Space Shuttle payload bay and used to transfer cargo to the ISS. The team will also be relying on “mixed-reality prototyping”, a process where virtual and augmented reality are used to solve engineering issues in the early design phase.

“We are excited to work with NASA to repurpose a historic piece of flight hardware, originally designed for low Earth orbit exploration, to play a role in humanity’s push into deep space,” said Pratt. “Making use of existing capabilities will be a guiding philosophy for Lockheed Martin to minimize development time and meet NASA’s affordability goals.”

The Deep Space Gateway will also rely on the Orion crew capsule’s advanced capabilities while crews are docked with the habitat. Basically, this will consist of the crew using the Orion as their command deck until a more permanent command module can be built and incorporated into the habitat. This process will allow for an incremental build-up of the habitat and the deep space exploration capabilities of its crews.

Credit: NASA

As Pratt indicated, when uncrewed, the habitat will rely on systems that Lockheed Martin has incorporated into their Juno and MAVEN spacecraft in the past:

“Because the Deep Space Gateway would be uninhabited for several months at a time, it has to be rugged, reliable and have the robotic capabilities to operate autonomously. Essentially it is a robotic spacecraft that is well-suited for humans when Orion is present. Lockheed Martin’s experience building autonomous planetary spacecraft plays a large role in making that possible.”

The Phase II work will take place over the next 18 months and the results (provided by NASA) are expected to improve our understanding of what is needed to make long-term living in deep space possible. As noted, Lockheed Martin will also be using this time to build their Deep Space Avionics Integration Laboratory, which will serve as an astronaut training module and assist with command and control between the Gateway and the Orion capsule.

Beyond the development of the Deep Space Gateway, NASA is also committed to the creation of a Deep Space Transport – both of which are crucial for NASA’s proposed “Journey to Mars”. Whereas the Gateway is part of the first phase of this plan – the “Earth Reliant” phase, which involves exploration near the Moon using current technologies – the second phase will be focused on developing long-duration capabilities beyond the Moon.

NASA’s Journey to Mars. NASA is developing the capabilities needed to send humans to an asteroid by 2025 and Mars in the 2030s. Credit: NASA/JPL

For this purpose, NASA is seeking to create a reusable vehicle specifically designed for crewed missions to Mars and deeper into the Solar System. The Deep Space Transport would rely on a combination of Solar Electric Propulsion (SEP) and chemical propulsion to transport crews to and from the Gateway – which would also serve as a servicing and refueling station for the spacecraft.

This second phase (the “Proving Ground” phase) is expected to culminate at the end of the 2020s, at which time a one-year crewed mission will take place. This mission will consist of a crew being flown to the Deep Space Gateway and back to Earth for the purpose of validating the readiness of the system and its ability to conduct long-duration missions independent of Earth.

This will open the door to Phase Three of the proposed Journey, the so-called “Earth Indepedent” phase. At this juncture, the habitation module and all other necessary mission components (like a Mars Cargo Vehicle) will be transferred to an orbit around Mars. This is expected to take place by the early 2030s, and will be followed (if all goes well) by missions to the Martian surface.

While the proposed crewed mission to Mars is still a ways off, the architecture is gradually taking shape. Between the development of spacecraft that will get the mission components and crew to cislunar space – the SLS and Orion – and the development of space habitats that will house them, we are getting closer to the day when astronauts finally set foot on the Red Planet!

Further Reading: NASA, Lockheed Martin

The post Ready to Leave Low Earth Orbit? Prototype Construction Begins for a Deep Space Habitat appeared first on Universe Today.

Dawn of the cosmos: Seeing galaxies that appeared soon after the Big Bang

sciencedaily.com - 2017. július 26. 20:33
Astronomers have discovered 23 young galaxies, seen as they were 800 million years after the Big Bang.

Gamma-ray burst captured in unprecedented detail

sciencedaily.com - 2017. július 26. 19:21
Gamma-ray bursts are among the most energetic and explosive events in the universe. They are also short-lived, lasting from a few milliseconds to about a minute. This has made it tough for astronomers to observe a gamma-ray burst in detail. Using a wide array of ground- and space-based telescope observations, astronomers constructed one of the most detailed descriptions of a gamma-ray burst to date.

Inside the September 2017 Issue

skyandtelescope.com-MostRecent - 2017. július 26. 18:23
PURCHASE PRINT ISSUE | PURCHASE DIGITAL ISSUE | PURCHASE BACK ISSUES | SUBSCRIBE

Tools of the Trade: Cassini's Saturn, LIGO's Detections, and Keeping Observing Logs

Tools both advanced and simple are crucial to astronomy. Cassini spent thirteen years imaging and collecting other data at Saturn — see some of the stunning photos. LIGO is so technologically impressive that it can detect a change in length of one part in one thousand billion billion. An amateur's observing log helps hone their own observational skills and can provide important data for cosmological events. Learn about the results of a search for advanced ET, explore the ethics of astrophotography, discover an amateur astronomer's solution to creating the perfect observing stool, and more, in the September 2017 issue of Sky & Telescope.

Feature Articles

An artist's conception of Cassini plunging through the gap between Saturn and its rings. NASA/JPL

Worlds of Wonder
With its 13-year stint at Saturn coming to a dramatic end, NASA's Cassini orbiter leaves a legacy of unparalleled beauty and scientific discovery.
By Luke Dones

Three Cosmic Chirps & Counting...
From the first discovery to subsequent finds, gravitational-wave signals from the universe's most exotic objects are transforming physics and astronomy.
By Vicky Kalogera

Keeping Track of the Night
An experienced observer describes the benefits and pleasures of keeping an astrojournal
By Bob King

Searching a Trillion Stars for ET
How I helped shrink the possibility that really advanced aliens are broadcasting far and wide.
By Robert H. Gray

Ethics in Astrophotography
Seeing isn't always believing in the digital age.
By Jerry Lodriguss

Beyond the Printed Page

An artist's concept of the TRAPPIST-1 system seen from one of its seven known planets, several of which lie within the star's habitable zone.
ESO / N. Bartmann /spaceengine.org

Mini-Flares Might Threaten Life Around Red Dwarf Stars
A new study of data archived from the Galaxy Evolution Explorer (GALEX) spacecraft is revealing just how hard life might be on exoplanets like those in the TRAPPIST-1 system.

TRAPPIST-1h Is Real
Astronomers have confirmed the existence of the seventh planet around the ultracool dwarf star TRAPPIST-1.

Tabby's Star Dims on Cue
Tabby's star, otherwise known as KIC 8462852, dimmed drastically in brightness, giving astronomers an opportunity to figure out what has been causing this star's weird behavior.

Lunar Librations and Phases of the Moon
Librations and other lunar data for September 2017.

ALSO IN THIS ISSUE

Dennis di Cicco

Diamond of Three Rings
A total solar eclipse offers the most spectacular of jewels.
By Fred Schaaf

Help Verify a Giant Ringed Exoplanet
For about 25 days in September, its ring system should cross an easily watched star.
By Alan MacRobert

The Enduring Mystery of Luna 2
Amateur observers claimed to see its impact— but no trace of the crash site has ever been found.
By Thomas A. Dobbins

Showpiece Doubles
Point your telescope toward these gems of the late-summer sky.
By Sue French

Table of Contents
See what else September's issue has to offer.

The post Inside the September 2017 Issue appeared first on Sky & Telescope.

Sky Surprises: New Comet ASASSN1, Nova in Scutum, and Supernova in Pisces!

skyandtelescope.com-MostRecent - 2017. július 26. 17:56

Between the discovery of Comet ASASSN1 and two stellar explosions, there's a lot happening in the sky this week. Take your telescope out and see what all the excitement's about. 

New Comet ASASSN1 (C/2017 O1) already glows aqua from carbon-laced gases. The comet is currently visible in the pre-dawn sky through modest-sized telescopes.
Rolando Ligustri

It feels like the FedEx guy just pulled up and dropped off a truckload of astronomical goodies. News arrived in my e-mail Monday about a new comet discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN). Founding member Benjamin Shappee and team have 498 bright supernovae and numerous other transient sources to their credit, but this is the group's first comet discovery, ASASSN1 (C/2017 O1).

The 15th-magnitude object was caught before dawn on July 19th in the constellation Cetus using data from the quadruple 14-cm "Cassius" telescope on Cerro Tololo, Chile. Don't be put off by that magnitude. The comet has brightened quickly in the past few days; visual observers are now reporting it at around magnitude +10 with a large (7′), weakly condensed coma. Chris Wyatt of Australia relates that a Swan band filter does a great job enhancing the apparent brightness and contrast of the coma, a sign this is a "gassy" comet.

I concur with Chris. On the morning of July 27.3 UT  from near Duluth, Minn., I found the comet large, faint and diffuse in my 10-inch at 57x from Duluth, Minn. The Swan filter gave it a welcome boost. Some fire haze was present in the air at the time which may account for it being fainter than expected. With a coma 8′ across, this thing's big!

This wide-view map shows Comet ASASSN1's location at the Cetus–Eridanus border south of Alpha (α) Ceti (Menkar) on July 26th.
Stellarium

Assuming the orbit remains close to the current calculation, Comet ASASSN1 will move northeast across Cetus and Taurus this summer and fall, slowly brightening as it approaches perihelion on October 14th in Perseus. It comes closest to the Earth four nights later, missing the planet by a cool 67 million miles. In a fun twist, ASASSN1 will slow down and spend the entire month of December and much of January within a few degrees of the North Star!

Comet ASSASN1 (C/2017 O1) moves steadily to the northeast in the coming month, becoming higher and easier to see before dawn. Stars are shown to magnitude +9 and comet positions are marked every 3 days at ~4 a.m. CDT. North is up.
Chris Marriott's SkyMap

Still, don't count your comets before they hatch. Or even after. Hairy stars can be fickle. There's a fair chance we're only seeing a temporary bright outburst of an intrinsically faint comet. But who knows? You and I will have to keep track of it to find out. Right now, ASASSN1 stands about 20° high in the southeastern sky as it crosses from Cetus into Eridanus. An 8-inch telescope should have no problem bringing it to life, especially now that the Moon's out of view and won't return to the morning sky until August 6th. You can stay in touch with the latest developments on Shappee's Twitter page.

In this photo from July 22nd, the new supernova SN 2017fgc shines at magnitude +13.7, far from the core of the elliptical galaxy NGC 474 in Pisces. You can use the comparison star magnitudes to estimate the supernova's brightness. North is up.
Stan Howerton

While you're out waiting for the comet to climb out of the haze, why not check out the new supernova, SN 2017fgc, which recently exploded into view in the 11th-magnitude galaxy NGC 474 in Pisces. At magnitude +13.7, you wouldn't call it "bright," but it's been rising since the DLT40 Survey discovered it on July 11th. Based on spectra taken of the object, it was still a couple weeks before maximum in mid-July, so I wouldn't be surprised if it continues to brighten.

This wide-field chart will help get you to NGC 474. It shows stars to magnitude +8. Use the photo above to navigate to the supernova. North is up.
Stellarium

Lots of supernovae appear close to the nuclei of their host galaxies and are notoriously difficult to discern in the dense fuzz of unresolved starlight. Not this one. It's "in the clear" 116″ east and 45″ north of the galaxy's center, so you won't break an eyeball trying to see it. An 8-inch scope magnifying around 150×-200× should coax it into view on a dark, moonless morning. It was very easy to spot at 157x in the 10-inch at magnitude +13.5 on July 27.4 UT. Take a minute with the side-by-side galaxies, a great sight in its own right.

Use this chart to find the nova, ASASSN17-hx. Then click here and here for more detailed AAVSO charts you can use to pinpoint its position and estimate its brightness. I observed the star on July 27.1 UT at magnitude +8.8; it had a distinctly red hue, typical for many novae.
Stellarium

When you bring this catastrophic pinpoint into focus, you'll be looking at what happens when a white dwarf star gains too much weight. After siphoning material from a close companion star for millennia, the dwarf exceeded its maximum weight of 1.4 solar masses and underwent a catastrophic gravitational collapse. The runaway fusion reaction that followed raced through the star, destroying it in one titanic blast. Overnight, a lowly white dwarf became a Type Ia supernova, bright enough to see from 96 million light years, the distance to the host galaxy.

The nova ASASSN-17hx jumps in brightness between June 23 and July 13 in this then-and-now animation.
Gianluca Masi / Virtual Telescope Project

Finally, a nova that's been dozing away at 12th-magnitude has started kicking out the jams! Since it's discovery on June 23rd, ASASSN-17hx has brightened nearly two full magnitudes, putting it within range of large binoculars and small telescopes.

As you can tell from the object's name, the ASAS-SN crew has been busy! Currently at about magnitude +9.0 (and still rising) in the Scutum Milky Way, it's well-placed for viewing at nightfall a few degrees below the tail of Aquila, the Eagle.

Like a Type Ia supernova, a nova occurs in a close binary star system where a normal star like our Sun is paired up with a white dwarf. Material pulled from the companion finds its way by way of accretion disk to the surface of the dwarf, where it accumulates, heats up, and ignites in a thermonuclear explosion. A sudden increase in brightness follows on the heels of the blast that raises the star from obscurity to binocular or even naked-eye visibility.

Novae occur in close binary systems where one star is a tiny but extremely compact white dwarf star. The dwarf pulls material from its companion into a disk around itself; some of the adopted material funnels to the surface and ignites in a nova explosion.
NASA

Unlike a supernova, the dwarf in this system remains intact and the process begins anew. It's estimated that small white dwarfs have repeat nova outbursts about once every 5 million years; for larger dwarfs, it's about every 30,000 years. The most massive must take care as they teeter close to the 1.4-solar mass limit. If a dwarf doesn't burn and destroy the accumulated fuel in time, the extra mass can push it past the limit to supernova-dom.

Guess it's time to open up those packages. Clear skies!

The post Sky Surprises: New Comet ASASSN1, Nova in Scutum, and Supernova in Pisces! appeared first on Sky & Telescope.

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