20 Canum Venaticorum

20 Canum Venaticorum is a single[10] variable star in the northern constellation of Canes Venatici, located 238 light years from the Sun. This object has the variable star designation AO Canum Venaticorum; 20 Canum Venaticorum is the Flamsteed designation. It is visible to the naked eye as a faint, white-hued star with a baseline apparent visual magnitude of +4.72.[2] The star is moving further from the Earth with a heliocentric radial velocity of +9 km/s.[5] Eggen (1971) listed this star as a member of the Hyades Stream.[11]

20 Canum Venaticorum
Observation data
Epoch J2000      Equinox J2000
Constellation Canes Venatici
Right ascension  13h 17m 32.54093s[1]
Declination +40° 34′ 21.3875″[1]
Apparent magnitude (V) +4.715[2]
Characteristics
Spectral type A9 II mF2[3]
B−V color index 0.30[2]
Variable type δ Sct[4]
Astrometry
Radial velocity (Rv)9.32±0.16[5] km/s
Proper motion (μ) RA: −113.761[1] mas/yr
Dec.: +19.858[1] mas/yr
Parallax (π)13.7210 ± 0.1581[1] mas
Distance238 ± 3 ly
(72.9 ± 0.8 pc)
Details
Mass2.43[2] M☉
Radius4[6] R☉
Luminosity63[2] L☉
Surface gravity (log g)2.97[7] cgs
Temperature7,314±42[2] K
Metallicity [Fe/H]0.18[6] dex
Rotational velocity (v sin i)15[8] km/s
Age750[2] Myr
Other designations
20 CVn, AO Canum Venaticorum, BD+41°2380, FK5 494, GC 18000, HD 115604, HIP 64844, HR 5017, SAO 44549[9]
Database references
SIMBADdata

This star has a stellar classification of A9 II mF2, which indicates the hydrogen line matches an A-type bright giant but the metal lines are closer to an F-type star. However, it does not appear to be an Am star as the Calcium K line is normal.[3] Earlier, Morgan and Abt (1972) assigned it a giant star class of F3 III.[12] It is classified as a Delta Scuti type variable star with a single radial pulsation mode providing the best fit to the observed variation.[4] Its brightness varies from magnitude +4.70 to +4.75 with a period of 2.92 hours.[13]

20 Canum Venaticorum is 750[2] million years old with 2.43[2] times the mass of the Sun and 4[6] time the Sun's radius. It is radiating 63[2] times the Sun's luminosity from its photosphere at an effective temperature of 7,314 K.[2]

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. Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal, 150 (3), 88, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88.
  3. Gray, R. O.; et al. (2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars", The Astronomical Journal, 121 (4): 2148, Bibcode:2001AJ....121.2148G, doi:10.1086/319956.
  4. Chadid, M.; et al. (August 2001), "20 CVn: A monoperiodic radially pulsating delta Scuti star", Astronomy and Astrophysics, 375: 113–121, Bibcode:2001A&A...375..113C, doi:10.1051/0004-6361:20010809.
  5. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  6. Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
  7. Adamczak, Jens; Lambert, David L. (August 2014), "Carbon and Oxygen Abundances across the Hertzsprung Gap", The Astrophysical Journal, 791 (1): 12, arXiv:1407.2157, Bibcode:2014ApJ...791...58A, doi:10.1088/0004-637X/791/1/58, 58.
  8. Royer, F.; et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics, 393: 897–911, arXiv:astro-ph/0205255, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943.
  9. "20 CVn". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-26.
  10. Eggleton, P. P.; Tokovinin, A. A. (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.
  11. Eggen, O. J. (December 1971), "Luminosities and Motions of the F-Type Stars. I. Luminosity and Metal Abundance Indices for Disk Population Stars", Publications of the Astronomical Society of the Pacific, 83 (496): 741, Bibcode:1971PASP...83..741E, doi:10.1086/129211.
  12. Morgan, W. W.; Abt, H. A. (February 1972), "The spectral classification of the F stars of intermediate luminosity", Astronomical Journal, 77: 35–37, Bibcode:1972AJ.....77...35M, doi:10.1086/111242.
  13. Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/s1063772917010085.
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