24 Vulpeculae

24 Vulpeculae is a single,[7] yellow-hued star in the northern constellation of Vulpecula. It is faintly visible to the naked eye with an apparent visual magnitude of 5.30.[2] The distance to this star can be estimated from its annual parallax shift of 7.45±0.27,[1] which yields a separation of roughly 440 light years. It is moving further away with a heliocentric radial velocity of +15 km/s.[4]

24 Vulpeculae
Observation data
Epoch J2000      Equinox J2000
Constellation Vulpecula
Right ascension  20h 16m 47.08593s[1]
Declination +24° 40′ 15.9624″[1]
Apparent magnitude (V) 5.30[2]
Characteristics
Spectral type G8III[2]
B−V color index 0.951[3]
Astrometry
Radial velocity (Rv)+15.3±0.3[4] km/s
Proper motion (μ) RA: +14.52[1] mas/yr
Dec.: −17.12[1] mas/yr
Parallax (π)7.45 ± 0.27[1] mas
Distance440 ± 20 ly
(134 ± 5 pc)
Absolute magnitude (MV)−0.68[2]
Details[2]
Mass3.41 M☉
Radius16[5] R☉
Luminosity191 L☉
Surface gravity (log g)2.48 cgs
Temperature4,981 K
Metallicity [Fe/H]−0.06 dex
Rotational velocity (v sin i)5.02[3] km/s
Age251 Myr
Other designations
24 Vul, BD+24° 4075, FK5 760, HD 192944, HIP 99951, HR 7753, SAO 88451[6]
Database references
SIMBADdata

This is an evolved giant star with a stellar classification of G8III,[2] having exhausted the hydrogen at its core and moved off the main sequence. It is a red clump giant, indicating it is presently on the horizontal branch and is generating energy through helium fusion in its core region.[8] The interferometry-measured angular diameter of 24 Vul is 1.08±0.02 mas,[9] which, at its estimated distance, equates to a physical radius of about 16 times the radius of the Sun.[5]

24 Vulpeculae is about 251[2] million years old and is spinning with a projected rotational velocity of 5.02 km/s.[3] It has 3.41 times the mass of the Sun and is radiating 191 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,981 K.[2] This is the probable (99.4% chance) source of X-ray emission coming from these coordinates.[10]

References
  1. 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. Takeda, Yoichi; et al. (August 2008), "Stellar Parameters and Elemental Abundances of Late-G Giants", Publications of the Astronomical Society of Japan, 60 (4): 781–802, arXiv:0805.2434, Bibcode:2008PASJ...60..781T, doi:10.1093/pasj/60.4.781.
  3. Hekker, S.; Meléndez, J. (2007), "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters", Astronomy and Astrophysics, 475 (3): 1003–1009, arXiv:0709.1145, Bibcode:2007A&A...475.1003H, doi:10.1051/0004-6361:20078233.
  4. Gontcharov, G. A. (2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065.
  5. Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
  6. "24 Vul". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-04-21.
  7. 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.
  8. Valentini, M.; Munari, U. (November 2010), "A spectroscopic survey of faint, high-Galactic-latitude red clump stars. I. The high resolution sample", Astronomy and Astrophysics, 522: A79, arXiv:1007.0207, Bibcode:2010A&A...522A..79V, doi:10.1051/0004-6361/201014870.
  9. Richichi, A.; et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431: 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039
  10. Haakonsen, Christian Bernt; Rutledge, Robert E. (September 2009), "XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources", The Astrophysical Journal Supplement, 184 (1): 138–151, arXiv:0910.3229, Bibcode:2009ApJS..184..138H, doi:10.1088/0067-0049/184/1/138.
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