A jet of molecular hydrogen arising from a forming high-mass star

Mar 07, 2007
Left: Near-infrared image of the M17 silhouette disk, discovered in 2004. The field of view is 27"x27", which roughly corresponds to 60000 AU x 60000 AU (AU stands for astronomical units). Right: Zoom on the central region at six selected wavelengths. The pictures were obtained with SINFONI. Each panel has a field of view of 4.8"x3.6" (i.e. 10560 AU x 7920 AU). While panels (b), (d), and (f) show the densest inner part of the silhouette disk, panels (c) and (e) reveal the H2 jet (individual emission knots are labelled with A, B, and C).

A team of European astronomers offer new evidence that high-mass stars could form in a similar way to low-mass stars, that is, from accretion of gas and dust through a disk surrounding the forming star. Their article, published in Astronomy & Astrophysics, reports the discovery of a jet of molecular hydrogen arising from a forming high-mass star located in the Omega nebula (M17). This detection confirms the hypothesis based on their earlier discovery that this forming high-mass star is surrounded by a large accretion disk.

While astronomers now understand the overall process of low-mass star formation very well, the formation process of massive stars is still very much under debate. Recent astronomical observations suggest that high-mass stars could form through accretion processes, just like low-mass stars do. For instance, in 2004, European astronomers discovered a large accretion disk that probably surrounds a forming high-mass star, in the star-forming region M17, also known as the Omega nebula and located at a distance of about 7000 light years.

Looking again at M17 with the new spectrograph SINFONI at the ESO-VLT, the same European group report discovering a jet of molecular hydrogen (H2) that apparently arises from the forming high-mass star. The picture below illustrates this discovery, which is being published in Astronomy & Astrophysics.

The ejection of material through a jet or an outflow is always linked to accretion of gas and dust, either onto the circumstellar disk or onto the central protostar. The detection of the H2 jet thus provides evidence that ongoing accretion processes occur in the M17 disk. The team also estimates the mass outflow and mass accretion rates, which suggest that a star of high mass is forming within the M17 disk. This is an additional clue that high-mass stars form in a similar way to lower mass stars.

Source: Journal Astronomy & Astrophysics

Explore further: NASA missions monitor a waking black hole

Related Stories

'Pick and mix' smart materials for robotics

5 hours ago

Researchers from the University of Cambridge have developed a simple 'recipe' for combining multiple materials with single functions into a single material with multiple functions: movement, recall of movement ...

Study concludes that racehorses are getting faster

5 hours ago

Despite a general consensus among scientists and in the racing industry that racehorse speed has plateaued, a new study from the University of Exeter has found that racehorses are getting quicker. Further ...

Recommended for you

NASA missions monitor a waking black hole

2 hours ago

NASA's Swift satellite detected a rising tide of high-energy X-rays from the constellation Cygnus on June 15, just before 2:32 p.m. EDT. About 10 minutes later, the Japanese experiment on the International ...

What is the habitable zone?

12 hours ago

The weather in your hometown is downright uninhabitable. There's scorching heatwaves, annual tyhpoonic deluges, and snow deep enough to bury a corn silo.

Galaxy survey to probe why the universe is accelerating

12 hours ago

We know that our universe is expanding at an accelerating rate, but what causes this growth remains a mystery. The most likely explanation is that a strange force dubbed "dark energy" is driving it. Now a ...

High resolution far-infrared all-sky image data release

14 hours ago

A research group led by a University of Tokyo researcher, using the AKARI satellite's Far-Infrared All-Sky data, have created all-sky image maps and released the full database to researchers around the world ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.