The water reservoir in a young planetary system

Nov 15, 2011
An artist's conception of an icy, planet-forming disk around the young star TW Hydrae. Astronomers have used the Herschel Space Observatory to detect copious amounts of water ice in this source. Credit: NASA/JPL-Caltech

(PhysOrg.com) -- Astronomers once thought that the process of star formation was more-or-less controlled by the simple coalescence of material by gravity, leading eventually to a new star. But they have come to realize that star formation entails a very complex series of stages. In one early step, the young star assembles a circumstellar disk of gas and dust. After a few million years, this disk has matured enough to begin to develop into planets.

The star TW Hydrae, located about 150 light-years from Earth, is only about 10 million years old, and is currently in this planet-forming stage. Because TW Hydrae is relatively close and bright, and because it rotates with its pole pointed nearly directly towards the Earth, scientists can view the star's disk of material nearly face on to study what is happening. One outstanding puzzle is how (like the Earth) can acquire their water. Most scenarios argue that the Earth's water arrived later on - via comets from the . Thus a focus of recent astronomy has been the study of the composition of the outer parts of the young stellar disk.

CfA astronomer Gary Melnick, a leading expert on water in space, joined with a team of colleagues to use the new Herschel to look for traces of water around TW Hydrae. Writing in the latest issue of Science, the team reports finding convincing evidence for a reservoir of water ice in this star's disk -- with inferred quantities of amounting to several thousand Earth-oceans. Moreover, they discovered from details of the ice chemistry that probably the ice comes from a mixture distributed throughout the system. The results lend convincing support to the current scenario of the origin of the Earth's oceans.

Explore further: Research finds numerous unknown jets from young stars and planetary nebulae

Related Stories

Detour: Planetary Construction Zone Ahead

Jun 24, 2005

Interstellar travelers might want to detour around the star system TW Hydrae to avoid a messy planetary construction site. Astronomer David Wilner of the Harvard-Smithsonian Center for Astrophysics (CfA) and ...

X-Ray Emission from Young Stars

Feb 05, 2010

(PhysOrg.com) -- The star TW Hydrae is located about 150 light-years from earth in the direction of the constellation of Hydrae, the Water Snake. This star is relatively young -- at about 10 million years ...

Pin-pointing water in space

Feb 26, 2010

(PhysOrg.com) -- Water is regarded as a key ingredient for life - and water exists plenty in the universe. Now scientists have found the precious element in a disk around a young star, similar to our Sun. ...

Measuring the clumpiness of proto-planetary disks

Jun 14, 2011

(PhysOrg.com) -- The process of star formation, once thought to involve just the simple coalescence of material under the influence of gravity, actually entails a complex series of stages, with the youngest ...

Solar System Shield

Jan 14, 2010

Water vapor in planet-forming disks may block ultraviolet radiation from destroying water and other important molecules for life, according to new calculations.

Recommended for you

Fermi satellite detects gamma-rays from exploding novae

19 hours ago

The Universe is home to a variety of exotic objects and beautiful phenomena, some of which can generate almost inconceivable amounts of energy. ASU Regents' Professor Sumner Starrfield is part of a team that ...

Image: Hubble serves a slice of stars

Jul 31, 2014

The thin, glowing streak slicing across this image cuts a lonely figure, with only a few foreground stars and galaxies in the distant background for company.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

omatumr
1.8 / 5 (5) Nov 15, 2011
Astronomers once thought that the process of star formation was more-or-less controlled by the simple coalescence of material by gravity, leading eventually to a new star. But they have come to realize that the young star assembles a circumstellar disk of gas and dust.


Thanks for the story.

If elements are layered in the circumstellar disk, as they were in the accretion disk that formed planets in the Solar System [1-7], then H20 will form at the interface of the outer and inner layers.

Hydrogen (H) was concentrated in the outer layer that formed giant gaseous planets. Oxygen (O) was contained mostly in the inner layer that formed rocky planets and ordinary meteorites.

1. www.omatumr.com/Origin.htm

2. www.omatumr.com/a...enon.pdf

3. www.nature.com/na...5a0.html

4. www.omatumr.com/a...lies.pdf

5. www.omatumr.com/lpsc.prn.pdf

6. http://arxiv.org/...410717v1

7. http://arxiv.org/...2.1499v1