15 Vulpeculae

A-type giant star in the constellation Vulpecula Vulpecula constellation map.svg center 280 right Red circle.svg 10 15 Vulpeculae 564 316 Location of 15 Vulpeculae (circled) J2000 Vulpecula 20 01 06.0486 +27 45 12.863 4.62 - 4.67 subgiant A4IIIm or kA5hA7mA7 (IV–V) +0.18 +0.15 α2 CVn −26.10 57.817 0.081 3.994 0.085 13.4427 0.1050 0.36 2.41 7,685 100 commas 61.6 logLT 1.79 7685 2rad Calculated, using the Stefan-Boltzmann law and the star's effective temperature and luminosity, with respect to the solar nominal effective temperature of commas 5,772 K: 15.0 3.53 +0.02 NT Vul 15 Vul +27°3587 1523 189849 98543 7653 88071 27753 15+Vulpeculae 15 Vulpeculae is a variable star in the northern constellation of Vulpecula, located approximately 243 light years away based on parallax measurements. It has the variable star designation NT Vulpeculae; 15 Vulpeculae is the Flamsteed designation. It is visible to the naked eye as a faint, white-hued star with a typical apparent visual magnitude of 4.66. This object is moving closer to the Earth with a heliocentric radial velocity of −26 km/s. thumb|An ultraviolet band light curve for NT Vulpeculae, adapted from Kuvshinov et al. (1976)|center The star is considered a marginal Am star with a stellar classification of A4 IIIm, matching an evolved A-type giant star. However, Gray & Garrison (1989) found a class of kA5hA7mA7 (IV–V), which matches a blend of subgiant and main sequence luminosity classes with the K-line (kA5) of an A5 star and the hydrogen (hA7) and metal (mA7) absorption lines of an A7 star. 15 Vulpeculae was a typical Am star when a main sequence, when evolving into a subgiant, it lost most of the peculiar properties of an Am star but still maintain some element abundance peculiarities. The star is 2.4 times more massive than the Sun and has expanded to four times the Sun's diameter.rad It is radiating 62 times the Sun's luminosity from its photosphere at an effective temperature of commas 7685 K. In 1974 L. P. Metik announced that 15 Vulpeculae is a variable star. It is an Alpha2 Canum Venaticorum-type variable with magnitude ranging from 4.62 down to 4.67 over a period of 14 days. There is evidence that 15 Vulpeculae may have a companion star, given the high margins of error in the astrometric measurements taken by Gaia DR3, as well as its unusually slow projected rotational velocity, which could also be explained if the star is being viewed pole-on. Notes References 2027458764012840576 Çay M. Taşkın Çay İpek H. Civelekler Betül Monthly Notices of the Royal Astronomical Society A critical evaluation of the elemental abundances and evolutionary status of 15 Vul (HD 189849): The first identification of an evolved Am star 2025-01-13 537 4 3054–3065 2501.07504 10.1093/mnras/staf034 free 2025MNRAS.537.3054C 275463214 Accepted manuscript 15 Vul 2018-03-15 2006yCat.2168....0M VizieR Online Data Catalog: Homogeneous Means in the UBV System (Mermilliod 1991) VizieR On-line Data Catalog: II/168. Originally Published in: Institut d'Astronomie 2168 Mermilliod J. C. 2006 Vizier catalog entry Kuvshinov V. M. Hildebrandt G. Schoeneich W. Photoelektrische Untersuchungen des Magnetfeldes und der Helligkeit der Am-Sterne 15 VUL und 68 Tau Astronomische Nachrichten January 1976 297 4 181–188 10.1002/asna.19762970405 1976AN....297..181K 2009yCat....102025S VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013) VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S 1 etal Samus N. N. Durlevich O. V. 2009 Elemental Abundance Analyses with DAO Spectrograms. XXXIX. The Am Stars 2 UMa and 15 Vul Çay İpek H. Teker Yelkenci Aysegul Adelman Saul J. Publications of the Astronomical Society of the Pacific 128 963 054201 May 2016 10.1088/1538-3873/128/963/054201 2016PASP..128e4201C 123542297 2005yCat.3244....0G VizieR Online Data Catalog: Catalog of Stellar Rotational Velocities (Glebocki+ 2005) VizieR On-line Data Catalog: III/244. Originally Published in: 2005csss...13..571G; 2005yCat.3244....0G 3244 Glebocki R. Gnacinski P. 2005 Vizier catalog entry 98543 10.1134/S1063773706110065 2006AstL...32..759G Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system Astronomy Letters 32 11 759–771 2006 Gontcharov G. A. 1606.08053 119231169 Kukarkin B. V. Kholopov P. N. Fedorovich V. P. Kireyeva N. N. Kukarkina N. P. Medvedeva G. I. Perova N. B. 62nd Name-List of Variable Stars Information Bulletin on Variable Stars March 1977 1248 1 1977IBVS.1248....1K https://ibvs.konkoly.hu/pub/ibvs/1201/1248.pdf 14 August 2025 Metik L. P. Three-colour photoelectric photometry of 15 Vul and gamma Cyg 1974IzKry..52...32M Krymskaia Astrofizicheskaia Observatoriia, Izvestiia 1974 52 32–34 20 01 06.0486 + 27 45 12.863 Category:A-type subgiants Category:Am stars Category:Alpha2 Canum Venaticorum variables Category:Vulpecula Category:Durchmusterung objects Vulpeculae, 15 189849 098543 7653 Vulpeculae, NT