R Trianguli

R Trianguli

Location of R Trianguli (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Triangulum
Right ascension	02^h 37^m 02.340^s[1]
Declination	+34° 15′ 51.34″[1]
Apparent magnitude (V)	5.4–12.6[2]
Characteristics
Spectral type	M3.5-8IIIe[2]
Apparent magnitude (B)	8.524±0.018
Apparent magnitude (G)	6.699±0.055
Apparent magnitude (R)	8.24
Apparent magnitude (J)	2.23±0.27
Apparent magnitude (H)	1.36±0.22
Apparent magnitude (K)	1.05±0.21
Variable type	Mira[2]
Astrometry
Radial velocity (Rv)	67.52±0.88[1] km/s
Proper motion (μ)	RA: +34.272 mas/yr[1] Dec.: −10.683 mas/yr[1]
Parallax (π)	2.4334 ± 0.2487 mas[1]
Distance	approx. 1,300 ly (approx. 410 pc)
Details
Mass	1.71[3] M☉
Radius	196±41[4] R☉
Luminosity	1,784[5] L☉
Surface gravity (log g)	−0.09[1] cgs
Temperature	3184±120[4] K
Other designations
R Tri, HR 758, HD 16210, HIP 12193, 2MASS J02370234+3415513, Gaia DR2 134874621777526400, Gaia DR3 134874621778128896[6]
Database references
SIMBAD	data

R Trianguli (abbreviated as R Tri) is a short-period oxygen-rich^[4] Mira variable in Triangulum with a period of 266.9 days,^[2] discovered by T. H. E. C. Espin in 1890.^[7] It is losing about 1.1×10⁻⁷ M_☉/yr, close to average for a short-period Mira variable.^[8] While most short-period Mira variables reside in the Galactic halo, R Trianguli is a member of the thick disk, and its proper motion is fairly high for its distance.^[4] Its angular diameter in the K band was measured in 2002 to be, on average, 5.22±0.30 mas, with a shape suggesting that there is an optically thin disk structure surrounding the star.^[4]

A visual band light curve for R Trianguli, plotted from AAVSO data^[9]

References

1. 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.
2. "General Catalog of Variable Stars table at VizieR". vizier.cds.unistra.fr.
3. Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics. 657: A7. arXiv:2109.10912. Bibcode:2022A&A...657A...7K. doi:10.1051/0004-6361/202142146. eISSN 1432-0746. ISSN 0004-6361.
4. Thompson, R. R.; Creech-Eakman, M. J.; Akeson, R. L. (May 2002). "Time-dependent Asymmetries in the Atmosphere of the Mira Variable R Trianguli through Infrared Interferometry". The Astrophysical Journal. 570 (1): 373–378. Bibcode:2002ApJ...570..373T. doi:10.1086/339736. S2CID 121032726.
5. McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012). "Fundamental Parameters and Infrared Excesses of Hipparcos Stars". Monthly Notices of the Royal Astronomical Society. 427 (1): 343–57. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x. S2CID 118665352.
6. "V* R Tri". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2023-06-29.
7. Gore, John Ellard (1903). The Stellar Heavens: An Introduction to the Study of the Stars and Nebulæ. Chatto & Windus. p. 52.
8. Jura, M. (February 1994). "The origin and evolution of short-period Miras in the solar neighborhood: Constraints on the life cycle of old stars". The Astrophysical Journal. 422: 102. Bibcode:1994ApJ...422..102J. doi:10.1086/173707.
9. "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.