Institute of Astronomy

Astronomy News

XMM-Newton Announcement of Opportunity (AO-16)

24 August 2016 - 9:21am
Proposals are solicited for observations with XMM-Newton in response to the sixteenth Announcement of Opportunity, AO-16, issued 23 August 2016. This AO covers the period May 2017 to April 2018 and is open to proposers from all over the world.

NASA gets in touch with spacecraft two years after it vanished

24 August 2016 - 9:20am

The twin STEREO spacecraft went missing while testing a system that would allow it to fly behind the sun

Astronomers identify a young heavyweight star in the Milky Way

22 August 2016 - 10:15am

Astronomers have identified a young star, located almost 11,000 light years away, which could help us understand how the most massive stars in the Universe are formed. This young star, already more than 30 times the mass of our Sun, is still in the process of gathering material from its parent molecular cloud, and may be even more massive when it finally reaches adulthood.

The researchers, led by a team at the University of Cambridge, have identified a key stage in the birth of a very massive star, and found that these stars form in a similar way to much smaller stars like our Sun – from a rotating disc of gas and dust. The results will be presented this week at the Star Formation 2016 conference at the University of Exeter, and are reported in the Monthly Notices of the Royal Astronomical Society.

In our galaxy, massive young stars – those with a mass at least eight times greater than the Sun – are much more difficult to study than smaller stars. This is because they live fast and die young, making them rare among the 100 billion stars in the Milky Way, and on average, they are much further away.

“An average star like our Sun is formed over a few million years, whereas massive stars are formed orders of magnitude faster — around 100,000 years,” said Dr John Ilee from Cambridge’s Institute of Astronomy, the study’s lead author. “These massive stars also burn through their fuel much more quickly, so they have shorter overall lifespans, making them harder to catch when they are infants.”

The protostar that Ilee and his colleagues identified resides in an infrared dark cloud - a very cold and dense region of space which makes for an ideal stellar nursery. However, this rich star-forming region is difficult to observe using conventional telescopes, since the young stars are surrounded by a thick, opaque cloud of gas and dust. But by using the Submillimeter Array (SMA) in Hawaii and the Karl G Jansky Very Large Array (VLA) in New Mexico, both of which use relatively long wavelengths of light to observe the sky, the researchers were able to ‘see’ through the cloud and into the stellar nursery itself. 

By measuring the amount of radiation emitted by cold dust near the star, and by using unique fingerprints of various different molecules in the gas, the researchers were able to determine the presence of a ‘Keplerian’ disc - one which rotates more quickly at its centre than at its edge.

“This type of rotation is also seen in the Solar System - the inner planets rotate around the Sun more quickly than the outer planets,” said Ilee. “It’s exciting to find such a disc around a massive young star, because it suggests that massive stars form in a similar way to lower mass stars, like our Sun.”

The initial phases of this work were part of an undergraduate summer research project at the University of St Andrews, funded by the Royal Astronomical Society (RAS). The undergraduate carrying out the work, Pooneh Nazari, said, “My project involved an initial exploration of the observations, and writing a piece of software to ‘weigh’ the central star. I’m very grateful to the RAS for providing me with funding for the summer project — I’d encourage anyone interested in academic research to try one!”

From these observations, the team measured the mass of the protostar to be over 30 times the mass of the Sun. In addition, the disc surrounding the young star was also calculated to be relatively massive, between two and three times the mass of our Sun. Dr Duncan Forgan, also from St Andrews and lead author of a companion paper, said, “Our theoretical calculations suggest that the disc could in fact be hiding even more mass under layers of gas and dust. The disc may even be so massive that it can break up under its own gravity, forming a series of less massive companion protostars.”

The next step for the researchers will be to observe the region with the Atacama Large Millimetre Array (ALMA), located in Chile. This powerful instrument will allow any potential companions to be seen, and allow researchers to learn more about this intriguing young heavyweight in our galaxy.

This work has been supported by a grant from the European Research Council.

References:
J.D. Ilee et al. ‘G11.92-0361 MM1: A Keplerian disc around a massive young proto O-star.’ Monthly Notices of the Royal Astronomical Society (2016): DOI: 10.1093/mnras/stw1912

D. H. Forgan et al. ‘Self-gravitating disc candidates around massive young stars.’ Monthly Notices of the Royal Astronomical Society (2016): DOI: 10.1093/mnras/stw1917

 

A young star over 30 times more massive than the Sun could help us understand how the most extreme stars in the Universe are born.

These massive stars have shorter overall lifespans, making them harder to catch when they are infants.John IleeA. Smith, Institute of Astronomy, CambridgeArtist’s impression of the disc and outflow around the massive young star


The text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Hyperactive galaxy could run out of gas in just 8 million years

22 August 2016 - 10:14am

The nearby galaxy M82 forms stars at a prodigious rate, but it is using up and blowing out far more gas than it takes in

Artificial black hole creates its own version of Hawking radiation

18 August 2016 - 9:39am

Artificial black hole creates its own version of Hawking radiation

Nature 536, 7616 (2016). http://www.nature.com/doifinder/10.1038/536258a

Author: Davide Castelvecchi

Result could be closest thing yet to an observation of the bizarre phenomenon.

Planetary science: Methane-filled canyons on Titan

18 August 2016 - 9:37am

Planetary science: Methane-filled canyons on Titan

Nature 536, 7616 (2016). doi:10.1038/536253a

The surface of Saturn's largest moon is etched with canyons that are flooded with liquid hydrocarbons, according to data from NASA's Cassini spacecraft.Valerio Poggiali of the Sapienza University of Rome and his team used radar aboard Cassini to measure elevations on Titan and map

NASA Prepares to Launch First U.S. Asteroid Sample Return Mission

18 August 2016 - 9:26am
NASA is preparing to launch its first mission to return a sample of an asteroid to Earth. The mission will help scientists investigate how planets formed and how life began, as well as improve our understanding of asteroids that could impact Earth.

Star snapped before and after nova explosion

18 August 2016 - 9:18am

Astronomers capture rare images of a white dwarf - before, during and after it exploded as a "classical nova".

Gaia's second anniversary marked by successes and challenges

17 August 2016 - 9:08am

Operating in the depths of space, far beyond the Moon's orbit, ESA's Gaia spacecraft has now completed two years of a planned five-year survey of the sky. Despite a series of unexpected technical challenges, the mission is on track to complete the most detailed and complex mapping of the heavens ever undertaken.

NASA urged to rejoin the hunt for gravitational waves

17 August 2016 - 9:06am

US National Academies has assessed US astrophysics schemes and is calling for NASA to rejoin a gravitational wave hunting mission, despite budget problems

Simulated black hole test backs Hawking prediction

17 August 2016 - 8:56am

Results from a lab experiment have lent support to one of Stephen Hawking's most important predictions about black holes.

The brightest stellar wildfire hosts impossibly huge stars

16 August 2016 - 8:56am

The 30 Doradus nebula is forming stars in a flat-out sprint, outpacing the local Milky Way by four orders of magnitude. Bring sunblock

Black hole made in the lab shows signs of quantum entanglement

16 August 2016 - 8:56am

Efforts to study black holes in the lab with versions that trap sound instead of light may have revealed a key prediction made by Stephen Hawking

Mating stars hide their modesty behind a thick veil of dust

16 August 2016 - 8:55am

Astronomers got their best ever look at merging stars when a pair called V1309 Scorpii got together in 2008, but now they have gone into hiding

Canadian meteorite may be first visitor from the Kuiper belt

15 August 2016 - 9:12am

Most meteorites come from the asteroid belt between Mars and Jupiter, but an extraterrestrial visitor that landed in 2000 may hail from further afield

Stunning images of Perseid meteor shower

15 August 2016 - 9:10am

Photographs and footage capture the annual Perseid meteor shower, which is more active than usual this year.

Here’s how to watch the great Perseid meteor shower tonight

12 August 2016 - 9:21am

Over the next few evenings the annual Perseid meteor shower will be reaching its peak, and putting on a great show

Hubble Uncovers a Galaxy Pair Coming in from the Wilderness

12 August 2016 - 9:20am

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The galaxies in the early universe were much smaller than our Milky Way and churned out stars at a rapid pace. They grew larger through mergers with other dwarf galaxies to eventually build the magnificent spiral and elliptical galaxies we see around us today. But astronomers using the Hubble Space Telescope have looked at two small galaxies that were left off the star party list. For many billions of years Pisces A and Pisces B lived in a vast intergalactic wilderness that was devoid of gas, which fuels star formation. They got left out in the cold.

'Spectacular fireballs' accompany annual meteor show

12 August 2016 - 9:19am

Observers say the annual astronomical event was marked with "spectacular fireballs" in the early hours of Friday.

Heating of Jupiter’s upper atmosphere above the Great Red Spot

11 August 2016 - 9:16am

Heating of Jupiter’s upper atmosphere above the Great Red Spot

Nature 536, 7615 (2016). doi:10.1038/nature18940

Authors: J. O’Donoghue, L. Moore, T. S. Stallard & H. Melin

The temperatures of giant-planet upper atmospheres at mid- to low latitudes are measured to be hundreds of degrees warmer than simulations based on solar heating alone can explain. Modelling studies that focus on additional sources of heating have been unable to resolve this major discrepancy. Equatorward transport of energy from the hot auroral regions was expected to heat the low latitudes, but models have demonstrated that auroral energy is trapped at high latitudes, a consequence of the strong Coriolis forces on rapidly rotating planets. Wave heating, driven from below, represents another potential source of upper-atmospheric heating, though initial calculations have proven inconclusive for Jupiter, largely owing to a lack of observational constraints on wave parameters. Here we report that the upper atmosphere above Jupiter’s Great Red Spot—the largest storm in the Solar System—is hundreds of degrees hotter than anywhere else on the planet. This hotspot, by process of elimination, must be heated from below, and this detection is therefore strong evidence for coupling between Jupiter’s lower and upper atmospheres, probably the result of upwardly propagating acoustic or gravity waves.