Stars well-endowed with gold have fewer companions

Nov 08, 2007

The chequered destinies of Australian Idol winners underscores what astronomers have known for a long time – star formation is complicated.

A new astronomical study adds an unexpected twist to the complications: stars well-endowed with gold and other heavy elements have fewer stellar companions. Researchers from The Australian National University (ANU) and the University of New South Wales (UNSW) believe their discovery could help track down Earth-like planets outside of our solar system.

“Ten years ago researchers found that stars with a large amount of heavy elements were more likely to be orbited by planets,” said report co-author Dr Charley Lineweaver from the Planetary Science Institute at ANU. “We still don’t understand why, but that’s the way it is. Our goal was to find out if such high-metallicity stars might also be more likely to be orbited by other stars.”

The Sun is a typical star in that about one per cent of its mass is made of heavy elements like oxygen, iron and gold. However, there are many stars with as little as one third of a per cent of their mass in heavy elements, while other stars have tens times that much. The amount of heavy elements somehow plays an important role in the types of object that form around a star.

Dr Lineweaver and Dr Daniel Grether from UNSW put together the most complete census of nearby stars, including the amount of heavy elements in these stars and whether the stars had planetary or stellar companions. They were surprised when they found the opposite of what was expected – stars with the highest content of heavy elements were less likely, not more likely, to have stellar companions.

“Our counterintuitive result does not yet have a good theoretical explanation, but we think that stars that form in different regions of our galaxy probably followed different paths to stardom,” Dr Grether said.

Detecting Earth-like planets has become a hot field for astronomers. Dr Lineweaver and Dr Grether believe that further research on the relationship between the amount of heavy elements in stars and the types of stellar and planetary companions orbiting them could assist in the search for worlds like our own.

The study is published in the latest edition of the Astrophysical Journal:
arxiv.org/abs/astro-ph/0612172

Source: Australian National University

Explore further: Image: Chandra's view of the Tycho Supernova remnant

add to favorites email to friend print save as pdf

Related Stories

Pitch black: Cosmic clumps cast the darkest shadows

May 22, 2014

(Phys.org) —Astronomers have found cosmic clumps so dark, dense and dusty that they throw the deepest shadows ever recorded. Infrared observations from NASA's Spitzer Space Telescope of these blackest-of-black ...

Recommended for you

Image: Chandra's view of the Tycho Supernova remnant

2 hours ago

More than four centuries after Danish astronomer Tycho Brahe first observed the supernova that bears his name, the supernova remnant it created is now a bright source of X-rays. The supersonic expansion of ...

Satellite galaxies put astronomers in a spin

Jul 24, 2014

An international team of researchers, led by astronomers at the Observatoire Astronomique de Strasbourg (CNRS/Université de Strasbourg), has studied 380 galaxies and shown that their small satellite galaxies almost always ...

Video: The diversity of habitable zones and the planets

Jul 24, 2014

The field of exoplanets has rapidly expanded from the exclusivity of exoplanet detection to include exoplanet characterization. A key step towards this characterization is the determination of which planets occupy the Habitable ...

Ultra-deep astrophoto of the Antenna Galaxies

Jul 24, 2014

You might think the image above of the famous Antenna Galaxies was taken by a large ground-based or even a space telescope. Think again. Amateur astronomer Rolf Wahl Olsen from New Zealand compiled a total ...

User comments : 0