Stars well-endowed with gold have fewer companions

November 8, 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: New half-life measurements could improve understanding of heavy elements

Related Stories

SOFIA Begins 2015 Southern Hemisphere Science Flights

June 22, 2015

NASA's Stratospheric Observatory for Infrared Astronomy, SOFIA, departed from Christchurch, New Zealand at 6:20 pm local time June 19 for the first of 15 planned Southern Hemisphere deployment science flights.

Recommended for you

The search for molecular oxygen among cosmic oxygen atoms

July 27, 2015

Oxygen is the third most abundant element in the universe (after hydrogen and helium) and of course it is important: all known life forms require liquid water and its oxygen content. For over thirty years, astronomers have ...

Hubble looks in on a galactic nursery

July 27, 2015

This dramatic image shows the NASA/ESA Hubble Space Telescope's view of dwarf galaxy known as NGC 1140, which lies 60 million light-years away in the constellation of Eridanus. As can be seen in this image NGC 1140 has an ...

Fossil star clusters reveal their age

July 27, 2015

Using a new age-dating method, an international team of astronomers has determined that ancient star clusters formed in two distinct epochs – the first 12.5 billion years ago and the second 11.5 billion years ago.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.