T Andromedae

T Andromedae (T And) is a variable star of the Mira type in the constellation Andromeda. Like all the stars of this kind, T And is a cool asymptotic giant branch star of spectral type M4e-M7.5e. Its brightness varies periodically, completing a cycle in 281 days. The peak luminosity, however, is different every variability cycle, but can reach a peak magnitude mv=7.70.[3]

Not to be confused with τ Andromedae.
T Andromedae

A visual band light curve for T Andromedae, plotted from AAVSO data[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 00h 22m 23.14956s[2]
Declination +26° 59′ 45.73676″[2]
Apparent magnitude (V) 7.70 – 14.30 variable [3]
Characteristics
Spectral type M4e-M7.5e[3]
B−V color index 2.63[4]
Variable type Mira[3]
Astrometry
Radial velocity (Rv)−90±10[4] km/s
Proper motion (μ) RA: −7.108[2] mas/yr
Dec.: −3.352[2] mas/yr
Parallax (π)0.5913 ± 0.0815 mas[2]
Distanceapprox. 5,500 ly
(approx. 1,700 pc)
Details
Mass4.9[5] M☉
Luminosity8.928[6] L☉
Surface gravity (log g)−0.51[5] cgs
Temperature3,235[5] K
Metallicity [Fe/H]−0.39[5] dex
Other designations
BD +26°43, HD 1795, SAO 73930
Database references
SIMBADdata

Thomas David Anderson discovered that T Andromedae is a variable star, in 1894.[7] The next year, Edward Charles Pickering examined archival photographic plates to derive a light curve for the star, and calculated a period of 281 days.[8]

Measurements of the angular size variations of T And made with the Palomar Testbed Interferometer show no clear correlation with the star's brightness variations.[9][10]

References
  1. "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.
  2. 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. General Catalogue of Variable Stars, s.v. T. And.
  4. "T And". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 8, 2018.
  5. Anders, F.; Khalatyan, A.; Queiroz, A. B. A.; Chiappini, C.; Ardevol, J.; Casamiquela, L.; Figueras, F.; Jimenez-Arranz, O.; Jordi, C.; Monguio, M.; Romero-Gomez, M.; Altamirano, D.; Antoja, T.; Assaad, R.; Cantat-Gaudin, T.; Castro-Ginard, A.; Enke, H.; Girardi, L.; Guiglion, G.; Khan, S.; Luri, X.; Miglio, A.; Minchev, I.; Ramos, P.; Santiago, B. X.; Steinmetz, M. (2022). "VizieR Online Data Catalog: StarHorse2, Gaia EDR3 photo-astrometric distances (Anders+, 2022)". Vizier Online Data Catalog. Bibcode:2022yCat.1354....0A.
  6. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  7. Espin, T. E.; Anderson, T. D. (January 1894). "New variable stars". Astronomy and Astro-Physics. 13: 63. Retrieved 23 February 2023.
  8. Pickering, E. C. (April 1895). "T Andromedae". Astrophysical Journal. 1: 305–308. Bibcode:1895ApJ.....1..305P. doi:10.1086/140056. Retrieved 23 February 2023.
  9. Creech-Eakman, M. J.; Thompson, R. R. (2009). "The Biggest, Baddest, Coolest Stars ASP Conference Series, Vol. 412". The Biggest. Astronomical Society of the Pacific. 412: 149. Bibcode:2009ASPC..412..149C.
  10. Thompson, R. R.; Creech-Eakman, M. J. (2004). American Astronomical Society Meeting Abstracts. Vol. 205. American Astronomical Society. Bibcode:2004AAS...205.1205T.
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