TW Horologii

TW Horologii
Observation data
Epoch J2000      Equinox J2000
Constellation Horologium
Right ascension 03h 12m 33.160s[1]
Declination 57° 19 17.5790 [1]
Apparent magnitude (V) +5.71
Characteristics
Spectral type C
Astrometry
Radial velocity (Rv)14.3 ± 2 km/s
Proper motion (μ) RA: 18.44 ± 0.31[1] mas/yr
Dec.: 13.20 ± 0.35[1] mas/yr
Parallax (π)3.11 ± 0.37[1] mas
Distanceapprox. 1,000 ly
(approx. 320 pc)
Other designations
HD 20234, HIP 14930, HR 977, IRAS 03112-5730, SAO 233037.[2]


TW Horologii is a star in the constellation Horologium. A semiregular variable and ageing red giant, it is in the asymptotic giant branch stage of its lifespan.[3]

TW Horologii is too far from earth for its parallax to be measured effectively; Guandalini and Cristallo calculated the luminosity of Mira variables based on their periods. Using a period of 158 days, they calculated the absolute magnitude of TW Horologii to be -4.62.[3]

References

  1. 1 2 3 4 5 van Leeuwen, F. (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.
  2. "TW Horologii". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 19 March 2016.
  3. 1 2 Guandalini, R.; Cristallo, S. (2013). "Luminosities of carbon-rich asymptotic giant branch stars in the Milky Way". Astronomy & Astrophysics 555. arXiv:1305.4203. Bibcode:2013A&A...555A.120G. doi:10.1051/0004-6361/201321225. A120 pages = 7.
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