Making massive stars

Aug 29, 2011
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 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 , 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 , even though maturation happens more quickly.

Explore further: Quest for extraterrestrial life not over, experts say

Related Stories

Making massive stars

Sep 10, 2010

Massive stars -- those with more than about eight times the mass of the sun -- are arguably the most important actors in the universe. Much hotter and more luminous than the sun, they live only hundreds of ...

Simulating the Birth of Massive Stars

Mar 09, 2010

(PhysOrg.com) -- Astronomers have made great strides recently in understanding how modest stars - those like the sun or smaller -- are formed.

Making Massive Stars

Sep 15, 2009

(PhysOrg.com) -- Our understanding of star formation leans heavily on observations of stars like the sun, namely, those that are modest in mass and that are born and evolve at a relatively leisurely pace. ...

Young stellar clusters

Jan 17, 2011

(PhysOrg.com) -- Most stars are thought to form in clusters rather than in isolation, as the gas and dust in a molecular cloud coalesces under the influence of gravity until clumps develop that are dense enough ...

Recommended for you

Quest for extraterrestrial life not over, experts say

Apr 18, 2014

The discovery of an Earth-sized planet in the "habitable" zone of a distant star, though exciting, is still a long way from pointing to the existence of extraterrestrial life, experts said Friday. ...

Continents may be a key feature of Super-Earths

Apr 18, 2014

Huge Earth-like planets that have both continents and oceans may be better at harboring extraterrestrial life than those that are water-only worlds. A new study gives hope for the possibility that many super-Earth ...

Exoplanets soon to gleam in the eye of NESSI

Apr 18, 2014

(Phys.org) —The New Mexico Exoplanet Spectroscopic Survey Instrument (NESSI) will soon get its first "taste" of exoplanets, helping astronomers decipher their chemical composition. Exoplanets are planets ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

omatumr
1 / 5 (4) Aug 30, 2011
How do massive stars form?


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

More news stories

Cosmologists weigh cosmic filaments and voids

(Phys.org) —Cosmologists have established that much of the stuff of the universe is made of dark matter, a mysterious, invisible substance that can't be directly detected but which exerts a gravitational ...

Let's put a sailboat on Titan

The large moons orbiting the gas giants in our solar system have been getting increasing attention in recent years. Titan, Saturn's largest moon, is the only natural satellite known to house a thick atmosphere. ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...