X Trianguli Australis is a star in the southern constellation Triangulum Australe. It is a red-hued carbon star approximately 1,140 light years (350 parsecs) from Earth.[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).[1] It ranges from magnitudes 5.03 to 6.05.[9] Its designation is from the variable star designation developed by German astronomer Friedrich Wilhelm Argelander.

It is a cool star, with of a surface effective temperature of 2,650 K (2,380 °C), yet luminous, emitting 13,000 times the luminosity of the Sun. Its angular diameter was measured at 13.82×10−3 arcseconds, which at its distance give a diameter 540 times that of the Sun.[7][a] If placed at the center of the Solar System, it would stretch out farther than Mars' orbit. Its absolute magnitude is −1.97.[3]

Notes

  1. ^ a b Calculated multiplying the angular diameter (in arcseconds) to the distance in parsecs: 0.01382 • 360 = diameter of 4.975 AU, which multiplied by 107.5 to convert from AU to R☉ give 535 R☉.

References

  1. ^ a b 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:0908.3228. Bibcode:2009MNRAS.400.1945T. doi:10.1111/j.1365-2966.2009.15588.x. S2CID 15358380.
  2. ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. ^ a b c d Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  4. ^ Warner, B. (1963). "Spectral classification of some Southern late-type peculiar stars". Monthly Notices of the Royal Astronomical Society. 126: 61. Bibcode:1963MNRAS.126...61W. doi:10.1093/mnras/126.1.61.
  5. ^ Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
  6. ^ Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
  7. ^ a b Rau, G.; et al. (April 2017). "The adventure of carbon stars. Observations and modeling of a set of C-rich AGB stars". Astronomy & Astrophysics. 600: 21. arXiv:1701.04331. Bibcode:2017A&A...600A..92R. doi:10.1051/0004-6361/201629337. S2CID 49571205. A92.
  8. ^ "V* X TrA". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 18 January 2013.
  9. ^ "X TrA". International Variable Star Index. American Association of Variable Star Observers. 11 November 2011. Retrieved 18 January 2013.
Allikas: https://en.wikipedia.org/wiki/X_Trianguli_Australis
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