Alpha Trianguli Australis

α Trianguli Australis
Location of α Trianguli Australis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Triangulum Australe
Right ascension 16h 48m 39.89508s[1]
Declination −69° 01′ 39.7626″[1]
Apparent magnitude (V) 1.91[2]
Characteristics
Spectral type K2Ib-IIa[3]
U−B color index +1.56[4]
B−V color index +1.44[4]
Astrometry
Radial velocity (Rv)−3.3[2] km/s
Proper motion (μ) RA: +17.99[1] mas/yr
Dec.: −31.58[1] mas/yr
Parallax (π)8.35 ± 0.15 mas[1]
Distance391 ± 7 ly
(120 ± 2 pc)
Absolute magnitude (MV)−3.68[3]
Details
Mass7[5] M☉
Radius143[3][a] – 167[6][b] R☉
Luminosity5,500[3] L☉
Surface gravity (log g)1.5[5] cgs
Temperature4,150[3][5] K
Metallicity [Fe/H]−0.06[5] dex
Age48[5] Myr
Other designations
Atria, HR 6217, CD −68°2822, HD 150798, SAO 253700, FK5 625, GC 22558, HIP 82273.[7]
Database references
SIMBADdata

Alpha Trianguli Australis (Latinised from α Trianguli Australis, abbreviated Alpha TrA, α TrA), officially named Atria /ˈeɪtriə/,[8][9] is the brightest star in the southern constellation of Triangulum Australe, forming an apex of a triangle with Beta Trianguli Australis and Gamma Trianguli Australis that gives the constellation its name (Latin for southern triangle).

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  4. ^ a b Cite error: The named reference clpl4_99 was invoked but never defined (see the help page).
  5. ^ a b c d e Cite error: The named reference aaa120_1_21 was invoked but never defined (see the help page).
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  8. ^ Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
  9. ^ "IAU Catalog of Star Names". Retrieved 28 July 2016.


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