Theta Delphini, a name Latinized from θ Delphini, is a single star in the northern constellation of Delphinus. It has an apparent visual magnitude of about 5.7, meaning that it is just barely visible to the naked eye under excellent viewing conditions. The distance to this star is approximately 2,050 light years from the Sun based on parallax. It is drifting closer with a radial velocity of −15 km/s.
The stellar classification of Theta Delphini is K3Ib, which means it is a K-type supergiant. 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. It has been described as a super-metal-rich star because of its high metallicity.
References
Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976. https://doi.org/10.1111%2Fj.1365-2966.2008.13596.x ↩
Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644. /wiki/ArXiv_(identifier) ↩
Famaey, B.; et al. (2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters". Astronomy and Astrophysics. 430: 165–186. arXiv:astro-ph/0409579. Bibcode:2005A&A...430..165F. doi:10.1051/0004-6361:20041272. https://doi.org/10.1051%2F0004-6361%3A20041272 ↩
Allen, J. S. "The Classification of Stellar Spectra". UCL Department of Physics and Astronomy: Astrophysics Group. Retrieved 1 January 2012. http://www.star.ucl.ac.uk/~pac/spectral_classification.html ↩
Ekström, S.; et al. (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. S2CID 85458919. /wiki/ArXiv_(identifier) ↩
Malagnini, M. L.; et al. (2000). "Observations and Atmospheric Parameters of Super-Metal-rich Candidates". Publications of the Astronomical Society of the Pacific. 112 (777): 1455. Bibcode:2000PASP..112.1455M. doi:10.1086/317714. https://doi.org/10.1086%2F317714 ↩