Astronomers identify a young heavyweight star in the Milky Way

August 22, 2016, University of Cambridge
Artist's impression of the disc and outflow around the massive young star. Credit: A. Smith, Institute of Astronomy, Cambridge.

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 held 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 . 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 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.

Explore further: Image: Hubble gazes at stars of the Large Magellanic Cloud

More information: J. D. Ilee et al, G11.92–0.61 MM1: A Keplerian disc around a massive young proto-O star, Monthly Notices of the Royal Astronomical Society (2016). DOI: 10.1093/mnras/stw1912

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FredJose
1.8 / 5 (5) Aug 22, 2016
There is a BIG disconnect between what was observed and the concluding statement that the bigger star formed or is forming in similar fashion as our own Sol.

The observation does not warrant the direct jump to the conclusion or inference. it only shows a certain physical characteristic which has nothing to do with the origins of either our sun or that of the observed entity. To make that kind of connection will require a much much more sophisticated observation and probably an observation point almost on top of the so-called proto-star, not one light years away.
Tuxford
1.4 / 5 (8) Aug 22, 2016
Agreed about the disconnect.

Merger maniacs are simply maniacs. They jump to conclusions like maniacs. They can see no other possibility. So they adapt their fantasy model to everything observed. To do otherwise means they will not be published. The entire science model is stuck in a faulty paradigm.

This massive star is not young, just growing rapidly from within, thereby likely of relatively low metallicity, since new material formed therein is non-metallic. Since more massive stars grow more rapidly, metallicity proportion therein diminishes rapidly as well.

And the massive outflows are a result of the growth from within, not without. These active massive stars blow winds outward, disrupting any possibility of accretion models. Yet the maniacs persist to support their faulty model, despite the illogic. Thus, they must be maniacs. How can one conclude otherwise??
RNP
4.2 / 5 (5) Aug 22, 2016
@Tuxford
Can you give a single shred of evidence for such outlandish claims?
wduckss
1 / 5 (4) Aug 22, 2016
@Tuxford
However they made the shift "..Keplerian 'disc - those which rotates more quickly at its center than at its edge.This type of rotation is also seen in the Solar System ..".
Fast rotation the central body is formed disk according to the laws of gravity. This excludes fast growth because the orbits are stable and there is no collapse of the body and substances that are in orbit. ..
Enthusiastic Fool
3 / 5 (2) Aug 23, 2016
@Tux
Can you elucidate the star forming process in LaViolette's "model" for me? It sounds to me like, "mass comes from nothing but only where there's already something." If there was a corestar that formed of non-metallic new matter and then continuously pumped out this cloud around it how could the proportion of metallicity go down over time when it started at 0?

How does new matter escape the gravity of the core? It must have high velocity; what imparts this velocity?
Tuxford
1 / 5 (4) Aug 23, 2016
How does new matter escape the gravity of the core?

The model includes the introduction of new energy - Genic Energy - under the fertile conditions of the dense core region as well. Hence, even small planetary bodies are too warm, like Pluto. And we observe unexplainably hot Jupiters within our solar system.

The greater the mass density, the more fertile the conditions for both new matter and new energy introduction through photon blue shifting. (Photon blue shifting is even observed in the smallest amount in the Pioneer Anomaly.) Thus, in supermassive bodies the genic energy production becomes extreme, causing outward pressure therein and a finite density reached in 'grey holes'. Thus, I predict that black holes actually allow light to escape radially, and periodically go unstable ejecting matter in order to reach a stable condition again.

In low density intergalactic space, new matter is formed extremely slowly, but forms the giant gas clouds and galactic halos.
RNP
3.7 / 5 (3) Aug 23, 2016
@Tuxford

@Tuxford
Can you give a single shred of evidence for such outlandish claims?


So, I take it the answer is no.
enteroctopus
1 / 5 (1) Aug 25, 2016
Why is a similar evolution surprising or worthy of such violent opposition? Ever ridden on a Mary-go-round? If you (mass) get the thing going at a swift run and then move toward the center the rpm increases accordingly. This is a fundamental property of matter under rotation.

Why would a massive (30 solar mass) star somehow behave differently than a smaller star, unless it swells to the critical mass and density, transitioning into a black hole? Perhaps this star is outside the previously-accepted range for a "sun-like" or "Keplerian" accretion disc to form. Essentially, we have a small statistical sampling from which to draw as relatively few very massive, very young stars are readily observable in great detail.

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