Theta Delphini

Theta Delphini
Diagram showing star positions and boundaries of the Delphinus constellation and its surroundings
Location of θ Delphini (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Delphinus
Right ascension 20h 38m 43.98687s[1]
Declination +13° 18′ 54.4484″[1]
Apparent magnitude (V) 5.71[2]
Characteristics
Spectral type K3Ib[2]
U−B color index +1.71[3]
B−V color index +1.52[3]
Astrometry
Radial velocity (Rv)-15.09[2] km/s
Proper motion (μ) RA: 3.53[1] mas/yr
Dec.: -0.47[1] mas/yr
Parallax (π)1.62 ± 0.40[1] mas
Distanceapprox. 2,000 ly
(approx. 600 pc)
Other designations
θ Del, 8 Del, BD+12° 4411, HD 196725, HIP 101882, SAO 106342, HR 7892, GC 28743[2]
Database references
SIMBADdata

Theta Delphini (θ Del, θ Delphini) is a star in the constellation Delphinus. It has an apparent magnitude of about 5.7, meaning that it is just barely visible to the naked eye under excellent viewing conditions. Based upon parallax measurements made by the Hipparcos spacecraft, this star is around 1300 light years away from the Sun.[1]

Iota Delphini's spectral type is K3Ib, meaning it is an K-type supergiant.[4] These types of stars form when relatively massive (10 to 30 M☉) stars like B-type main sequence stars run out of hydrogen to fuse and start cooling down.[5]

References

  1. 1 2 3 4 5 6 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. 1 2 3 4 "iot Del". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 15 January 2016.
  3. 1 2 Fernie, J. D. (1983). "New UBVRI photometry for 900 supergiants". Astrophysical Journal Supplement Series. 52: 7–22. Bibcode:1983ApJS...52....7F. doi:10.1086/190856.
  4. ↑ Allen, J. S. "The Classification of Stellar Spectra". UCL Department of Physics and Astronomy: Astrophysics Group. Retrieved 1 January 2014.
  5. ↑ Ekström, S.; Georgy, C.; Eggenberger, P.; Meynet, G.; Mowlavi, N.; Wyttenbach, A.; Granada, A.; Decressin, T.; Hirschi, R.; Frischknecht, U.; Charbonnel, C.; Maeder, A. (2012). "Grids of stellar models with rotation. I. Models from 0.8 to 120 M⊙ at solar metallicity (Z = 0.014)". Astronomy & Astrophysics. 537: A146. arXiv:1110.5049. Bibcode:2012A&A...537A.146E. doi:10.1051/0004-6361/201117751.
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