HE 1523-0901
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Libra |
| Right ascension | 15h 26m 01.2s [1] |
| Declination | -9° 11′ 38″ [1] |
| Apparent magnitude (V) | 11.1 [1] |
| Distance | ~7500 [2] ly (~2,300 [2] pc) |
HE 1523-0901 is the designation given to a red giant star in the Milky Way galaxy approximately seven and a half kilo light years from Earth. It is thought to be a second generation Population II, or metal-poor, star ([Fe/H] = −2.95). The star was found in the sample of bright metal-poor halo stars from the Hamburg/ESO Survey by Anna Frebel and collaborators. The group's research was published in the May 10 2007 issue of The Astrophysical Journal.[3]
The star's age, as measured by ESO's Very Large Telescope, is 13.2 billion years. This makes it the oldest object yet discovered in the galaxy,[4] and nearly as old as the estimated age of the universe itself (13.7 billion years as measured by WMAP). HE 1523-0901 is the first star whose age was determined using the decay of the radioactive elements uranium and thorium in tandem with measurements of several neutron capture elements.[5] It is believed to have formed directly from the remnants of the first-generation stars that reached the end of their longevity and exploded as supernovae early in the history of known matter.
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[edit] Designation
The designation "HE 1523-0901" indicates that the star is part of the Hamburg/ESO Survey catalog. A list of astronomical catalogues can be used to find which catalog a star or other object is from based on its prefix. Most objects are listed in several catalogs and will often be known by several different designations.
[edit] Observation
HE 1523-0901 is approximately 0.8 Solar masses. It can be viewed particularly well from the southern hemisphere with the use of a small telescope. It can also be observed from southern locations in the northern hemisphere, such as Greece.
[edit] References
- ^ a b c "Oldest Star Image Gallery". Anthony Ayiomamitis. http://www.perseus.gr/Astro-Star-Oldest-HE-1523-0901.htm. Retrieved 2008-02-20.
- ^ a b "Homepage of Anna Frebel". Anna Frebel. http://www.as.utexas.edu/~anna/he1523.html. Retrieved 2008-02-20.[dead link]
- ^ Frebel, A.; et al. (2007). "Discovery of HE 1523–0901, a Strongly r-Process-enhanced Metal-poor Star with Detected Uranium". The Astrophysical Journal 660 (2): L117. arXiv:astro-ph/0703414. Bibcode 2007ApJ...660L.117F. doi:10.1086/518122.
- ^ "Nearby Star Is A Galactic Fossil". Science Daily. May 11, 2007. http://www.sciencedaily.com/releases/2007/05/070510151902.htm. Retrieved 2007-05-10.
- ^ "A galactic fossil: Star is found to be 13.2 billion years old". PhysOrg. May 10, 2007. http://physorg.com/news98033554.html. Retrieved 2007-05-12.
- "Astronomers discover HE 1523-0901 star: Almost as old as universe". iTWire. http://www.itwire.com.au/content/view/12098/1066/. Retrieved 2007-05-15.
- "Ancient star nearly as old as the universe". MSNBC.com. http://www.msnbc.msn.com/id/18612697/. Retrieved 2007-05-14.
[edit] External links
- ESO press release
- McDonald Observatory / UT press release
- Hamburg/ESO Survey Homepage
- Astronomy magazine
- CCD image based on 2-hrs total exposure
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