X Trianguli Australis

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X Trianguli Australis
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Triangulum Australe
Right ascension 15h 14m 19.17535s [1]
Declination −70° 04′ 46.1052″ [1]
Apparent magnitude (V) +5.63
Distance 1173 ly
(360 pc)
Spectral type C5.5(Nb).
Other designations
HR 5644, HD 134453,
CP-69 2267, HIP 74582,
SAO 253062, GC 20436

X Trianguli Australis is a star in the constellation Triangulum Australe. It is a red-hued carbon star with an average apparent magnitude of +5.89. It is approximately 1173 light years (360 parsecs) from Earth,[1] though this could vary by up to 200 light years.[2] It is a semi-regular variable star with two periods of around 385 and 455 days, and is of spectral type C5.5(Nb).[3] It ranges from magnitudes 5.03 to 6.05.[4] Its designation is from the variable star designation developed by German astronomer Friedrich Wilhelm Argelander.

It is a cool star, with estimates of its surface temperature ranging from 2200 to 2700 Kelvin.[2] A giant star, its diameter is 400 times that of the sun, and if placed at the center of the Solar System would stretch out to 30% further than Mars' orbit. Its absolute magnitude is −2.0.[2]


  1. ^ a b c "X Trianguli Australis – Carbon Star". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. Retrieved 18 January 2013. 
  2. ^ a b c Kaler, Jim (19 October 2012). "X Trianguli Australis". Stars. University of Illinois. Retrieved 18 January 2013. 
  3. ^ Tabur, V.; Bedding, T. R. (2009). "Long-term Photometry and Periods for 261 Nearby Pulsating M Giants". Monthly Notices of the Royal Astronomical Society. 400 (4): 1945–61. arXiv:0908.3228Freely accessible. Bibcode:2009MNRAS.400.1945T. doi:10.1111/j.1365-2966.2009.15588.x. 
  4. ^ "X TrA". International Variable Star Index. American Association of Variable Star Observers. 11 November 2011. Retrieved 18 January 2013.