V669 Cassiopeiae

V669 Cassiopeiae or V669 Cas is an OH/IR star, a type of particularly cool red giant, with a spectral type of M9III.

V669 Cassiopeiae

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Cassiopeia
Right ascension	01h 33m 51.21s[1]
Declination	62° 26′ 53.2″[1]
Apparent magnitude (V)	17.48[2]
Characteristics
Evolutionary stage	AGB[3]
Spectral type	M9III[3]
Apparent magnitude (J)	16.747[1]
Apparent magnitude (H)	11.232[1]
Apparent magnitude (K)	7.097[1]
Variable type	Mira?[4]
Astrometry
Proper motion (μ)	RA: −2.813[5] mas/yr Dec.: −2.147[5] mas/yr
Parallax (π)	1.9523 ± 0.7049 mas[5]
Distance	2,100[6] pc
Details
Radius	370 – 702[6] R☉
Luminosity	10,000 - 36,000[6] L☉
Temperature	3,000[6] K
Database references
SIMBAD	data

With a mean visual apparent magnitude 17.5, V669 Cassiopeiae varies with an amplitude of about half a magnitude.^[2] In the mid-infrared L band, its magnitude range is 1.57 to 3.02. It is listed as a possible Mira variable, but with the extremely long period of 1,994 days.^[4]

Jan Herman and Harm Jan Habing reported in 1985 that the star's OH maser emission varied in intensity with a 1994 day period.^[7] In 1990, Paolo Persi et al. showed that V669 Cassiopeiae varied in infrared brightness,^[8] and for that reason it was given its variable star designation in 1993.^[9]

The distance and physical properties of V669 Cassiopeiae are highly uncertain. Based on parallax, it is about 1,600 light years away, but a distance of about 20,000 light years has been derived based on observations of masers around the star.^[3] Based on a luminosity derived from its pulsations and spectral energy distribution, it would be at a distance of 6,850 light years.^[6]

See also

• List of largest known stars

References

1. Cutri, Roc M.; et al. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
2. Jayasinghe, T.; Kochanek, C. S.; Stanek, K. Z.; Shappee, B. J.; Holoien, T. W. -S.; Thompson, Todd A.; Prieto, J. L.; Dong, Subo; Pawlak, M.; Shields, J. V.; Pojmanski, G.; Otero, S.; Britt, C. A.; Will, D. (2018). "The ASAS-SN catalogue of variable stars I: The Serendipitous Survey". Monthly Notices of the Royal Astronomical Society. 477 (3): 3145. arXiv:1803.01001. Bibcode:2018MNRAS.477.3145J. doi:10.1093/mnras/sty838.
3. De Beck, E.; Decin, L.; De Koter, A.; Justtanont, K.; Verhoelst, T.; Kemper, F.; Menten, K. M. (2010). "Probing the mass-loss history of AGB and red supergiant stars from CO rotational line profiles. II. CO line survey of evolved stars: Derivation of mass-loss rate formulae". Astronomy and Astrophysics. 523: A18. arXiv:1008.1083. Bibcode:2010A&A...523A..18D. doi:10.1051/0004-6361/200913771. S2CID 16131273.
4. Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
5. 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.
6. Lombaert, R.; Decin, L.; De Koter, A.; Blommaert, J. A. D. L.; Royer, P.; De Beck, E.; De Vries, B. L.; Khouri, T.; Min, M. (2013). "H₂O vapor excitation in dusty AGB envelopes. A PACS view of OH 127.8+0.0". Astronomy and Astrophysics. 554. arXiv:1505.07696. Bibcode:2013A&A...554A.142L. doi:10.1051/0004-6361/201218974. S2CID 98319654.
7. Herman, J.; Habing, H. J. (March 1985). "Time variations and shell sizes of OH masers in late-type stars". Astronomy and Astrophysics, Supplement Series. 59: 523–555. Bibcode:1985A&AS...59..523H. Retrieved 29 August 2024.
8. Persi, P.; Ferrari-Toniolo, M.; Shivanandan, K.; Ranieri, M.; Marenzi, A. (October 1990). "Infrared photometry up to 34 mu.m of the type II OH/IR sources OH 127.8-0.0 and OH 345.0+15.7". Astronomy and Astrophysics. 237: 153–158. Bibcode:1990A&A...237..153P. Retrieved 29 August 2024.
9. Kazarovets, E. V.; Samus, N. N.; Goranskij, V. P. (February 1993). "The 71st Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 3840 (3840): 1. Bibcode:1993IBVS.3840....1K. Retrieved 29 August 2024.