Beta Trianguli Australis

Beta Trianguli Australis, Latinized from β Trianguli Australis, is a double star in the southern constellation of Triangulum Australe. It is approximately 40.37 light-years (12.38 parsecs) from Earth and has an apparent visual magnitude of +2.85.^[2] This star has a relatively high rate of proper motion across the celestial sphere.^[9] It is a F-type main-sequence star with a stellar classification of F1 V.^[3] Beta TrA has a 14th magnitude optical companion at an angular separation of 155 arcseconds.

Beta Trianguli Australis

Location of β Trianguli Australis (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Triangulum Australe
Right ascension	15h 55m 08.56206s[1]
Declination	−63° 25′ 50.6155″[1]
Apparent magnitude (V)	2.85[2]
Characteristics
Spectral type	F1 V[3]
U−B color index	+0.05[2]
B−V color index	+0.29[2]
Astrometry
Radial velocity (Rv)	+0.4[4] km/s
Proper motion (μ)	RA: −188.66[1] mas/yr Dec.: −401.85[1] mas/yr
Parallax (π)	80.79 ± 0.16 mas[1]
Distance	40.37 ± 0.08 ly (12.38 ± 0.02 pc)
Absolute magnitude (MV)	+2.37[5]
Details[6]
Mass	1.56[7] M☉
Radius	1.976±0.021 R☉
Luminosity	9.30±0.17 L☉
Surface gravity (log g)	4.219±0.066[8] cgs
Temperature	7,171±35 K
Metallicity [Fe/H]	−0.29±0.10 dex
Rotational velocity (v sin i)	69.63 km/s
Age	674[7] Myr
Other designations
β TrA, CD−63° 1135, FK5 589, GJ 601, HD 141891, HIP 77952, HR 5897, SAO 253346, LTT 6339[9]
Database references
SIMBAD	data

Observation with the Spitzer Space Telescope reveals what appears to be an excess infrared emission from this star. This suggests the presence of circumstellar material in this system, making it a debris disk candidate.^[10] This star may be a member of the Beta Pictoris moving group, an association of about 17 stars that share a common origin and a similar motion through space. If it is a member of this group, this would put the age of β TrA at about 12 million years; the same as the group itself.^[11]

Modern legacy

β TrA appears on the flag of Brazil, symbolising the state of Santa Catarina.^[12]

References

1. van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600
2. Nicolet, B. (October 1978). "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System". Astronomy and Astrophysics Supplement Series. 34: 1–49. Bibcode:1978A&AS...34....1N.
3. Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637, S2CID 119476992
4. Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick (eds.), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E
5. 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.
6. Rains, Adam D.; et al. (April 2020), "Precision angular diameters for 16 southern stars with VLTI/PIONIER", Monthly Notices of the Royal Astronomical Society, 493 (2): 2377–2394, arXiv:2004.02343, Bibcode:2020MNRAS.493.2377R, doi:10.1093/mnras/staa282
7. David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
8. Allende Prieto, C.; et al. (June 2004), "S⁴N: A spectroscopic survey of stars in the solar neighborhood. The Nearest 15 pc", Astronomy and Astrophysics, 420 (1): 183–205, arXiv:astro-ph/0403108, Bibcode:2004A&A...420..183A, doi:10.1051/0004-6361:20035801, S2CID 14393039
9. "LTT 6339 -- High proper-motion Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-01-28
10. Koerner, D. W.; et al. (February 2010), "New Debris Disk Candidates Around 49 Nearby Stars" (PDF), The Astrophysical Journal Letters, 710 (1): L26 – L29, Bibcode:2010ApJ...710L..26K, doi:10.1088/2041-8205/710/1/L26, S2CID 122844702
11. Nakajima, Tadashi; Morino, Jun-Ichi; Fukagawa, Misato (September 2010), "Potential Members of Stellar Kinematical Groups within 20 pc of the Sun", The Astronomical Journal, 140 (3): 713–722, Bibcode:2010AJ....140..713N, doi:10.1088/0004-6256/140/3/713
12. Astronomy of the Brazilian Flag, FOTW Flags Of The World website