Signatures of the first stars

Apr 15, 2005

A primitive star with extremely low iron content has been discovered by an international research team from Sweden, Japan, Germany, USA, Australia and Great Britain. This indicates the original composition of the gas from which the star formed had low iron content. The results are published in Nature online this week.

In 2001, the giant star HE0107-5240 was discovered among a large number of stars examined as part of the Hamburg/ESO* survey. Detailed studies revealed that the star had by far the lowest iron content ever recorded - 200 000 times lower than the Sun. Previously, only stars with iron contents up to 10 000 times lower than the solar value were known. Recently, a second star was discovered with similar iron content, designated HE1327-2326.

"These two stars are the most chemically primitive stars known, and therefore provide information on the nature of the first objects that formed in the Universe after the Big Bang," Paul Barklem from Uppsala university, Sweden, says.

Notably, HE1327-2326 is not a giant but a dwarf or sub-giant star, meaning that it is comparatively unevolved. The abundance of some chemical elements in evolved giant stars may have been altered by processes occurring during the star's evolution; however, in an unevolved dwarf or sub-giant star we expect that the chemical composition is close to the original composition of the gas from which the star formed.

Analysis of the spectra for both stars, obtained with the world's largest telescopes, allows the chemical composition of each star to be determined. The stars' chemical abundances show similarities, such as large abundances of carbon and nitrogen, which suggest that these two stars may have formed in a similar way. The detailed interpretation of the chemical signatures of these two stars, and similar stars for which we continue to search, should help us to understand exactly how the first generations of stars were formed, and which elements were produced when they ended their lives in supernova explosions.

Source: Swedish Research Council

Explore further: Spacewalking astronauts finish extensive, trick cable job

add to favorites email to friend print save as pdf

Related Stories

Planets can alter each other's climates over eons

Feb 20, 2015

A new study sheds light on how exoplanets in tightly-packed solar systems interact with each other gravitationally by affecting one another's climates and their abilities to support alien life.

The controversy over interstellar messaging

Feb 20, 2015

Should we beam messages into deep space, announcing our presence to any extraterrestrial civilizations that might be out there? Or, should we just listen? Since the beginnings of the modern Search for Extraterrestrial ...

Telescopes give shape to furious black hole winds

Feb 19, 2015

NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) and ESA's (European Space Agency) XMM-Newton telescope are showing that fierce winds from a supermassive black hole blow outward in all directions—a ...

Getting a grip on exotic atomic nuclei

Feb 18, 2015

A new model describing atomic nuclei, proposed by a physicist from the University of Warsaw Faculty of Physics, more accurately predicts the properties of various exotic isotopes that are created in supernova explosions or ...

Recommended for you

Spacewalking astronauts finish extensive, trick cable job

3 hours ago

(AP)—Spacewalking astronauts successfully completed a three-day cable job outside the International Space Station on Sunday, routing several-hundred feet of power and data lines for new crew capsules commissioned ...

Could the Milky Way become a quasar?

Feb 27, 2015

A quasar is what you get when a supermassive black hole is actively feeding on material at the core of a galaxy. The region around the black hole gets really hot and blasts out radiation that we can see billions ...

User comments : 0

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.