HE 1523-0901

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**HE 1523-0901**
Observation data Epoch J2000
Constellation (pronunciation)	Libra
Right ascension	15^h 26^m 01.2^s ^[1]
Declination	-9° 11′ 38″ ^[1]
Apparent magnitude (V)	11.1 ^[1]
Distance	7500 (approx.) ^[2] ly (2300 (approx.) ^[2] pc)

HE 1523-0901 is the designation given to a red giant star located in the Milky Way galaxy. 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/European Southern Observatory survey by Anna Frebel and collaborators. The group's research was published in the May 10 issue of the Astrophysical Journal.

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,^[3] and nearly as old as the estimated age of the universe itself (13.7 billion years as measure 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.^[4] It is believed to have formed directly from the remnants of the first generation stars that reached the end of their lifespans and exploded as supernovas early in the history of the universe.

1 Designation
2 Observation
3 References
4 External links

[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 eight-tenths the size of the Sun. 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.