Making massive stars
An infrared image of the massive young star IRAS 20216+4104. (It is so bright that the image contains several camera artifacts including the red, bead-like ring and the dark center.) New research shows that some standard aspects of low mass star formation can apply to massive stars. Credit: NASA Spitzer
How do massive stars form? Stars with more than about eight times as much mass as the sun are arguably the most important actors in the universe. Although they live only hundreds of millions of years, they are much hotter and more luminous than the sun, and during their brief lifetimes their nuclear furnaces produce a wide range of chemical elements (the universe was created with primarily hydrogen and helium). In their dramatic deaths as supernovae they disburse these elements into the cosmos. They also can leave behind neutron stars or black holes.
The best understood models of star formation work well with lower mass stars like those the size of the sun -- their birth and maturation are comparatively slow and measured processes, and moreover the various stages can be observed with modern telescopes. By contrast, the physical processes associated with massive star birth are more extreme. A young massive star is so bright, for example, that outward pressure from its radiation retards the accretion of matter; in a smaller star that accretion causes it to continue to grow in mass as it matures. Moreover, massive stars mature very quickly (in less than a few hundred thousand years compared with millions of years for stars like the sun). As a result, there are not many young massive ones around at any given time in which to study the processes associated with their birth.
CfA astronomers Katharine Johnston, Eric Keto, Tom Robitaille, and a colleague, decided to apply their best models of low mass star formation to the case of a massive young star located about 5500 light-years away in the constellation of Cygnus. They wanted to test whether recent infrared and submillimeter observations of the dust around the source (and in its immediate surroundings) could perhaps exclude models of star formation used in low mass cases. Writing in the latest issue of Monthly Notices of the Royal Astronomical Society, the scientists report that, to the contrary, the low-mass models work tolerably well. The team is able to determine the mass of the star (about 12 solar-masses) and the accretion rate of material onto the star (about 130 Earth-masses per year). They also find that the star is surrounded by an envelope of about 600 solar-masses of gas and dust, and a large circumstellar disk of radius 9200 astronomical units. Their results indicate that at least the basic process of accretion and disk formation apply to the conditions around massive stars, even though maturation happens more quickly.
Provided by
Harvard-Smithsonian Center for Astrophysics
-
From lemons to lemonade: Reaction uses carbon dioxide to make carbon-based semiconductor,
32 comments
-
Thioridazine kills cancer stem cells in human while avoiding toxic side-effects of conventional cancer treatments,
3 comments
-
SpaceX private rocket blasts off for space station (Update),
42 comments
-
Climate scientists say they have solved riddle of rising sea,
31 comments
-
SpaceX capsule has 'new car' smell, astronauts say (Update),
2 comments
-
revamping general concept and cosmological principle
May 25, 2012
-
Transiting Exoplanet Light Curve
May 25, 2012
-
Math behind Theoretical Physics
May 24, 2012
-
Do we know whats at the center of galaxies yet?
May 23, 2012
-
Structure of the Milky Way?
May 20, 2012
-
What would it take to terraform Pluto and Charon?
May 19, 2012
- More from Physics Forums - General Astronomy
More news stories
Yale study concludes public apathy over climate change unrelated to science literacy
Are members of the public divided about climate change because they don't understand the science behind it? If Americans knew more basic science and were more proficient in technical reasoning, would public consensus match ...
32 minutes ago |
not rated yet |
2
|
10 million years needed to recover from mass extinction
It took some 10 million years for Earth to recover from the greatest mass extinction of all time, latest research has revealed.
Space & Earth / Earth Sciences
33 minutes ago |
not rated yet |
0
|
Sophisticated simulations predict future warming
The chances of our planet being hit by a global warming of 3 degrees Celsius by 2050 is as likely as it being hit by an increase of 1.4 degrees, new research shows. Presented in the journal Nature Geoscience, the British study ...
Space & Earth / Earth Sciences
May 22, 2012 |
4.4 / 5 (9) |
51
Aliens don't want to eat us, says former SETI director
Alien life probably isnt interested in having us for dinner, enslaving us or laying eggs in our bellies, according to a recent statement by former SETI director Jill Tarter.
Space & Earth / Space Exploration
May 25, 2012 |
4.4 / 5 (13) |
39
Kyoto Protocol architect 'frustrated' by climate dialogue
UN climate talks are going nowhere, as politicians dither or bicker while the pace of warming dangerously speeds up, one of the architects of the Kyoto Protocol told AFP.
May 23, 2012 |
3.7 / 5 (7) |
39
Change in developmental timing was crucial in the evolutionary shift from dinosaurs to birds: study
At first glance, it's hard to see how a common house sparrow and a Tyrannosaurus Rex might have anything in common. After all, one is a bird that weighs less than an ounce, and the other is a dinosaur that ...
Computer model used to pinpoint prime materials for efficient carbon capture
When power plants begin capturing their carbon emissions to reduce greenhouse gases and to most in the electric power industry, it's a question of when, not if it will be an expensive undertaking.
'Unzipped' carbon nanotubes could help energize fuel cells, batteries
Multi-walled carbon nanotubes riddled with defects and impurities on the outside could replace some of the expensive platinum catalysts used in fuel cells and metal-air batteries, according to scientists at ...
T cells 'hunt' parasites like animal predators seek prey, study shows
By pairing an intimate knowledge of immune-system function with a deep understanding of statistical physics, a cross-disciplinary team at the University of Pennsylvania has arrived at a surprising finding: T cells use a movement ...
Manufacturing genes to attack flu virus
An international research team has manufactured a new protein that can combat deadly flu epidemics.
Same gene that stunts infants' growth also makes them grow too big: research
UCLA geneticists have identified the mutation responsible for IMAGe* syndrome, a rare disorder that stunts infants' growth. The twist? The mutation occurs on the same gene that causes Beckwith-Wiedemann syndrome, which makes ...
Aug 30, 2011
Rank: 1 / 5 (4)
That is an excellent question!
The nebular model of star formation from an interstellar cloud of mostly H,He will probably not answer this question correctly.
It now seems more likely that H,He are waste products from the dense, energetic stellar core that accumulate as a photon-emitting cloud called the "photosphere" [1,2]
1. "Is the Universe Expanding?" The Journal of Cosmology 13, 4187-4190 (2011)
http://journalofc...102.html
2. "Neutron Repulsion", The APEIRON Journal, in press, 19 pages (2011)
http://arxiv.org/...2.1499v1
With kind regards,
Oliver K. Manuel
Former NASA Principal
Investigator for Apollo