Subscribe free to our newsletters via your
. 24/7 Space News .

Stars can be late parents
by Staff Writers
Paris (ESA) Feb 04, 2013

Weighing the planet-forming disc around a nearby star.

Using the unique capabilities of ESA's Herschel space observatory, astronomers have accurately 'weighed' a star's disc, finding it still has enough mass to spawn 50 Jupiter-sized planets, several million years after most other stars have already given birth.

Proto-planetary discs contain all the raw ingredients for building planets. They are composed mainly of cold molecular hydrogen gas, which is highly transparent and essentially invisible.

Usually, it is much easier to measure the emission from 'contaminants' such as the small fraction of dust mixed in the gas, or other gas constituents, to make estimates of the total disc mass.

In the past, this technique has caused significant uncertainties in the estimations of molecular hydrogen mass, but thanks to the far-infrared wavelength capabilities and sensitivity of Herschel, astronomers have used a new, more accurate method, using a close relative of molecular hydrogen called hydrogen deuteride, or 'heavy' molecular hydrogen.

Since the ratio of 'normal' and 'heavy' molecular hydrogen gas is extremely well known from measurements in our local solar neighbourhood, this approach provides a means to 'weigh' a star's total disc mass with ten times higher accuracy than ever before.

Using this technique, a substantial mass of gas was detected in a disc encircling TW Hydrae, a young star just 176 light-years away in the constellation of Hydra.

"We did not expect to find so much gas around this 10-million-year-old star," says Professor Edwin Bergin of the University of Michigan, lead author of the report published in Nature.

"This star has significantly more mass than required to make our own Solar System and could make a much more exotic system with planets more massive than Jupiter."

Observing such a massive disc around TW Hydrae is unusual for stars of this age because, within a few million years, most material is typically incorporated into the central star or giant planets, or has been swept away by its strong stellar wind.

"With a more refined mass, we can learn more about this system in terms of its planet-bearing potential and the availability of ingredients that might be able to support a planet with life," adds Professor Bergin.

Indeed, in a separate Herschel survey, scientists had already identified TW Hydrae as a star with a disc that contains enough water to fill the equivalent of several thousand Earth oceans.

The new method of 'weighing' a disc means that the volume of materials available - including water - could have been underestimated, in this system and in others.

A re-evaluation of the masses of discs around other stars of varying ages will provide more insight into the planet-building process.

"There may be different outcomes regarding planet formation for systems of varying ages," says co-author Professor Thomas Henning of the Max Planck Institute for Astronomy, Germany.

"Just as the ages at which people have children span a range, TW Hydrae seems to lie at the edge of that range for stars, showing that this particular system may have needed longer to form planets, and that it might be a late parent."

"The detection of heavy molecular hydrogen was made possible thanks to the new observing capabilities offered by Herschel, providing this leap forward in weighing the disc around this star," adds Goran Pilbratt, ESA's Herschel project scientist.


Related Links
Lands Beyond Beyond - extra solar planets - news and science
Life Beyond Earth

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Researchers develop model for identifying habitable zones around star
University Park PA (SPX) Feb 04, 2013
Researchers searching the galaxy for planets that could pass the litmus test of sustaining water-based life must find whether those planets fall in a habitable zone, where they could be capable of having liquid water and sustaining life. New work, led by a team of Penn State researchers, will help scientists in that search. Using the latest data, the Penn State Department of Geosciences te ... read more

US, Europe team up for moon fly-by

Russia to Launch Lunar Mission in 2015

US, Europe team up for moon fly-by

Mission would drag asteroid to the moon

AAS Division For Planetary Sciences Issues Statement On Mars 2020 Program

Curiosity Maneuver Prepares for Drilling

Ridges on Mars suggest ancient flowing water

Changes on Mars Caused by Seasonal Thawing of CO2

Iran's Bio-Capsule Comes Back from Space

A Hero For Humankind: Yuri Gagarin's Spaceflight

Internet wonders which monkey Iran sent into space

Sierra Nevada Corporation and Lockheed Martin Space Systems Company Partner On Dream Chaser Programs

Reshuffle for Tiangong

China to launch 20 spacecrafts in 2013

Mr Xi in Space

China plans manned space launch in 2013: state media

NASA to Send Inflatable Pod to International Space Station

ISS to get inflatable module

ESA workhorse to power NASA's Orion spacecraft

Competition Hopes To Fine Tune ISS Solar Array Shadowing

Zenit Engine Worked Normally

NASA Launches Rocket from Wallops Flight Facility in Virginia

Intelsat 27 Launch Unsuccessful

Floating platform unharmed after Zenit launch failure

Herschel Finds Past-Prime Star May Be Making Planets

Stars can be late parents

Researchers develop model for identifying habitable zones around star

TW Hydrae: There's more to astronomers' favorite planetary nursery than previously thought

Novel materials shake ship scum

Penn Research Shows Mechanism Behind Wear at the Atomic Scale

NTU research embraces laser and sparks cool affair

Bioinspired fibers change color when stretched

The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement