HE 0107−5240
Template:Short description Template:Starbox begin Template:Starbox image Template:Starbox observe Template:Starbox astrometry Template:Starbox orbit Template:Starbox detail | luminosity= Template:Val<ref name=Caffau2025/> | temperature= 5,111<ref name=Caffau2025/> | gravity = 2.46<ref name=Caffau2025/> | metal_fe = −5.3<ref name=sp1/> | rotation= | age_gyr = 13<ref name=Caffau2025/> | component2 = B | mass2 = >0.14<ref name=Caffau2025/> }} Template:Starbox catalog Template:Starbox reference Template:Starbox end
HE 0107−5240 is a binary star system in the constellation of Phoenix, consisting of extremely metal-poor Population II stars. It is located roughly Template:Convert away from Earth. This system is one of the most metal-poor known in our Galaxy, with a metallicity [Fe/H] = Template:Val;<ref name="sp1">Template:Cite journal</ref> i.e. it has just Template:Sfrac of the metal that the Sun has. Because of its very low metallicity, it is believed to be one of the earliest Population II stars to have formed. If so, then it is also very old, with an age of roughly 13 billion years. Because the stars are not completely metal-free, they do not belong to the first generation of stars (the hypothetical Population III). Pop III stars converted the pristine hydrogen, helium, and lithium formed by the Big Bang into heavier elements, such as carbon, oxygen, and metals.
HE0107−5240 was found by Norbert Christlieb and colleagues at the University of Hamburg in Germany as a byproduct of the Hamburg/ESO Survey for faint quasars with the 1m ESO Schmidt telescope. Follow-up observations were made at the Siding Spring 2.3 m Telescope and high-resolution spectra were taken at the European Southern Observatory in Chile, using one of the units of the Very Large Telescope. In 2005, a second star with an even smaller iron abundance, HE 1327-2326 ([Fe/H]=-5.4), was found, also in the Hamburg/ESO survey. In 2014 an even more metal poor star was announced: SMSS J031300.36−670839.3.<ref name="Keller2014">Template:Cite journal</ref> In 2020, HE 0107−5240 was revealed to be an spectroscopic binary system. The orbit has an period of Template:Convert and a low eccentricity. The companion has a mass of at least 0.14 solar masses.<ref name=Caffau2025>Template:Cite arXiv</ref>
See also
Other ultra low metallicity / ultra metal poor stars
Notes
References
<references/>
- Christlieb N., Bessell M.S., Gustafsson B., Korn A., Barklem P.S., Karisson T., Mizuno-Wiedner M., Rossi S., "A stellar relic from the early Milky Way", Nature, 419, 904-906 (2002)