SMSS J031300.36−670839.3 (shortened as SMSS J0313−6708; informally abbreviated to SM0313) is a star in the

Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...

at a distance of from Earth. With an age of approximately 13.6 billion years, it is one of the

oldest star The age of the oldest known stars approaches the age of the universe, about 13.8 billion years. Some of these are among the first stars from reionization (the stellar dawn), ending the Dark Ages about 370,000 years after the Big Bang. ...

s known. Another star,

HD 140283 HD 140283 (also known as the Methuselah star) is a metal-poor subgiant star about 200 light years away from the Earth in the constellation Libra, near the boundary with Ophiuchus in the Milky Way galaxy. Its apparent magnitud ...

, was considered to be older, but there is uncertainty in values of its age. This makes SM0313 the oldest known star with an accurate determination of its age. The star formed only about 200 million years after the

Big Bang The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature. Various cosmological models based on the Big Bang concept explain a broad range of phenomena, including th ...

and has been shining for 13.6 billion years. The star's very low upper limit of

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

of less than one ten-millionth the iron level of the Sun, suggests that it is one of the first

Population II In 1944, Walter Baade categorized groups of stars within the Milky Way into stellar populations. In the abstract of the article by Baade, he recognizes that Jan Oort originally conceived this type of classification in 1926. Baade observed th ...

stars, formed from a gas cloud enriched by some of the first (

Population III In 1944, Walter Baade categorized groups of stars within the Milky Way into stellar populations. In the abstract of the article by Baade, he recognizes that Jan Oort originally conceived this type of classification in 1926. Baade observed that ...

) stars. SMSS J031300.36-670839.3 also has a much higher

carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...

supply compared to iron, more than a thousand times greater. Apart from

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

, which appeared in the

, the star also contains carbon,

magnesium Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...

, and

calcium Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...

, which could have been formed in a low-energy

supernova A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...

Methylidyne Methylidyne, or (unsubstituted) carbyne, is an organic compound whose molecule consists of a single hydrogen atom bonded to a carbon atom. It is the parent compound of the carbynes, which can be seen as obtained from it by substitution of other f ...

(CH) is also detected by its

absorption line Absorption spectroscopy is spectroscopy that involves techniques that measure the absorption (electromagnetic radiation), absorption of electromagnetic radiation, as a function of frequency or wavelength, due to its interaction with a sample. Th ...

. No

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

has been detected. The star is a K-class red giant. The star was discovered by a team led by

Australian National University The Australian National University (ANU) is a public university, public research university and member of the Group of Eight (Australian universities), Group of Eight, located in Canberra, the capital of Australia. Its main campus in Acton, A ...

astronomers. The discovery was reported in ''

Nature Nature is an inherent character or constitution, particularly of the Ecosphere (planetary), ecosphere or the universe as a whole. In this general sense nature refers to the Scientific law, laws, elements and phenomenon, phenomena of the physic ...

'' on 9 February 2014 and indicates that the supernovae of the population III stars may not have been as powerful as previously thought. The discovery was made possible by the

SkyMapper SkyMapper is a fully automated 1.35 m (4.4 ft) wide-angle optical telescope at Siding Spring Observatory in northern New South Wales, Australia. It is one of the telescopes of the Research School of Astronomy and Astrophysics of the ...

, a fully automated

optical telescope An optical telescope gathers and focus (optics), focuses light mainly from the visible spectrum, visible part of the electromagnetic spectrum, to create a magnification, magnified image for direct visual inspection, to make a photograph, or to co ...

Siding Spring Observatory Siding Spring Observatory near Coonabarabran, New South Wales, Australia, part of the Research School of Astronomy & Astrophysics (RSAA) at the Australian National University (ANU), incorporates the Anglo-Australian Telescope along with a coll ...

near

Coonabarabran Coonabarabran () is a town in Warrumbungle Shire that sits on the divide between the Central West and North West Slopes regions of New South Wales, Australia. At the 2021 census, the town had a population of 2,387, Material was copied from th ...

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

, Australia.

References

{{DEFAULTSORT:SMSS J031300.36-670839.3 20140209 Hydrus Population II stars

See also

References