LP Andromedae

LP Andromedae (often abbreviated to LP And) is a carbon star in the constellation Andromeda. It is also a Mira variable[6] whose mean apparent visual magnitude is 15.12 and has pulsations with an amplitude of 1.50 magnitudes[2] and a period of 614 days.[7]

LP Andromedae
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 23h 34m 27.5216s[1]
Declination +43° 33′ 01.2996″[1]
Apparent magnitude (V) 15.12 variable[2]
Characteristics
Spectral type C8,3.5e[3]
Apparent magnitude (G) 16.9041[1]
Apparent magnitude (J) 9.623[4]
Apparent magnitude (H) 6.355[4]
Apparent magnitude (K) 2.71[5]
Variable type Mira[6]
Astrometry
Proper motion (μ) RA: −21.313±0.532 [1] mas/yr
Dec.: −22.058±0.453[1] mas/yr
Parallax (π)2.5002 ± 0.3626[1] mas
Distanceapprox. 1,300 ly
(approx. 400 pc)
Absolute bolometric
magnitude (Mbol)		−5.21±0.26[7]
Details[7]
Mass0.8 M☉
Radius340 – 420 R☉
Luminosity2,900 – 16,200 L☉
Temperature2,100 – 3,350 K
Other designations
2MASS J23342752+4333012, IRAS 23320+4316
Database references
SIMBADdata

In 1974 LP Andromedae, known then as IRC+40540, was identified as a carbon star and also shown to be variable.[8] It had previously been suspected of variability during the 2 Micron All Sky Survey (2MASS). A detailed study of its spectrum showed an unusually cool star with a basic class of C8, and Swan band strength of 3.5. It also showed strong C13 isotopic bands.[3] The period was narrowed down to around 614 days, one of the longest periods known for a Mira variable.[9]

This star has a dusty envelope with an estimated mass of 3.2 M☉, fueled by the star itself which is losing mass at a rate 1.9×10−5 M☉/yr. Such a high mass loss rate should place LP Andromedae close to the end of its asymptotic giant branch evolution. The envelope extends to a distance of 3 parsec from the star, and is mainly made of silicon carbide and carbon particles.[7]

References
  1. 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.
  2. Database entry, The Catalina Surveys periodic variable star catalog. (Drake+, 2014), A. J. Drake et al., CDS ID J/ApJS/213/9 Accessed on line 2018-11-14.
  3. Cohen, M. (1979). "Circumstellar envelopes and the evolution of carbon stars". Monthly Notices of the Royal Astronomical Society. 186 (4): 837–852. Bibcode:1979MNRAS.186..837C. doi:10.1093/mnras/186.4.837.
  4. Cutri, R. M.; Skrutskie, M. F.; Van Dyk, S.; et al. (June 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.
  5. Menzies, J. W.; Feast, M. W.; Whitelock, P. A. (June 2006). "Carbon-rich Mira variables: radial velocities and distances". Monthly Notices of the Royal Astronomical Society. 369 (2): 783–790. Bibcode:2006MNRAS.369..783M. CiteSeerX 10.1.1.255.9712. doi:10.1111/j.1365-2966.2006.10323.x. S2CID 18684991.
  6. N. N. Samus; O. V. Durlevich; et al. "LP And database entry". Combined General Catalog of Variable Stars (2017 ed.). CDS. Retrieved 2018-11-14.
  7. Men'shchikov, A. B.; Balega, Y. Y.; Berger, M.; Driebe, T.; Hofmann, K.-H.; Maximov, A. F.; Schertl, D.; Shenavrin, V. I.; Weigelt, G. (March 2006). "Near-infrared speckle interferometry and radiative transfer modelling of the carbon star LP Andromedae". Astronomy and Astrophysics. 448 (1): 271–281. Bibcode:2006A&A...448..271M. doi:10.1051/0004-6361:20052976.
  8. Lockwood, G. W. (1974). "Near-infrared photometry of unidentified IRC stars. II". The Astrophysical Journal. 192: 113. doi:10.1086/153041.
  9. Alksnis, A. (1989). "On the Variability of the Dusty Carbon Star LP and". Information Bulletin on Variable Stars. 3396: 1. Bibcode:1989IBVS.3396....1A.
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