Gamma Doradus

Gamma Doradus, Latinized from γ Doradus, is the third-brightest star in the southern constellation of Dorado.[10] It is faintly visible to the naked eye with an apparent visual magnitude of approximately 4.25, and is a variable star, the prototype of the class of Gamma Doradus variables.[2] The star is located at a distance of 67 light years from the Sun based on parallax,[1] and is drifting further away with a radial velocity of +25 km/s.[5] Based on its motion through space, it appears to be a member of the IC 2391 supercluster.[11]

Gamma Doradus
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Dorado
Right ascension 04h 16m 01.58823s[1]
Declination −51° 29′ 11.9191″[1]
Apparent magnitude (V) 4.25[2]
Characteristics
Evolutionary stage Main sequence
Spectral type F1V[3]
U−B color index +0.03[4]
B−V color index +0.30[4]
R−I color index +0.16[4]
Variable type γ Dor[2]
Astrometry
Radial velocity (Rv)+25.2±0.5[5] km/s
Proper motion (μ) RA: +99.463[1] mas/yr
Dec.: +183.353[1] mas/yr
Parallax (π)48.8984 ± 0.2817[1] mas
Distance66.7 ± 0.4 ly
(20.5 ± 0.1 pc)
Absolute magnitude (MV)2.72[2]
Details
Mass1.56±0.06[6] M☉
Radius1.85+0.25
−0.10[1] R☉
Luminosity6.999+0.051
−0.052[1] L☉
Luminosity (bolometric)7.0[2] L☉
Surface gravity (log g)4.29±0.18[7] cgs
Temperature6,906+89
−423[1] K
Metallicity [Fe/H]+0.05±0.14[7] dex
Rotational velocity (v sin i)56.6±0.5[8] km/s
Age535–1207[6] Myr
Other designations
γ Dor, CD−51°1066, CPD−51°524, FK5 157, GC 5179, GJ 9150, HD 27290, HIP 19893, HR 1338, SAO 233457, PPM 333343[9]
Database references
SIMBADdata

This is an F-type main-sequence star with a stellar classification of F1V.[3] It is a pulsating variable that varies in brightness by less than a tenth of a magnitude owing to nonradial gravity wave oscillations.[2] Four pulsation frequencies have been identified with periods of 17.6, 12.8, 16.3, and 18.2 hours.[8][12] The star is around 0.5–1.2 billion years old and is spinning with a projected rotational velocity of 57 km/s.[8] It has 1.6[6] times the mass of the Sun and 1.9[1] times the Sun's radius. The star is radiating seven[1] times the luminosity of the Sun from its photosphere at an effective temperature of 6,906 K.[1]

An infrared excess has been detected at multiple frequencies,[13] indicating that the star is being orbited by a pair of debris disks.[14]

References
  1. 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.
  2. Kaye, Anthony B.; et al. (July 1999). "Gamma Doradus Stars: Defining a New Class of Pulsating Variables". Publications of the Astronomical Society of the Pacific. 111 (761): 840–844. Bibcode:1999PASP..111..840K.
  3. Gray, R. O.; et al. (2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID 119476992.
  4. Hoffleit, D.; Warren, Jr., W. H. HR 1338, database entry. The Bright Star Catalogue (5th Revised ed.). "V/50". CDS. Retrieved November 17, 2008.
  5. Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
  6. Esposito, Thomas M.; et al. (July 2020). "Debris Disk Results from the Gemini Planet Imager Exoplanet Survey's Polarimetric Imaging Campaign". The Astronomical Journal. 160 (1): 44. arXiv:2004.13722. Bibcode:2020AJ....160...24E. doi:10.3847/1538-3881/ab9199. 24.
  7. Bruntt, H.; et al. (February 2008). "A spectroscopic study of southern (candidate) γ Doradus stars. II. Detailed abundance analysis and fundamental parameters". Astronomy and Astrophysics. 478 (2): 487–496. arXiv:0711.3819. Bibcode:2008A&A...478..487B. doi:10.1051/0004-6361:20078523.
  8. Brunsden, E.; et al. (April 2018). "Frequency and mode identification of γ Doradus from photometric and spectroscopic observations*". Monthly Notices of the Royal Astronomical Society. 475 (3): 3813–3822. arXiv:1803.06890. Bibcode:2018MNRAS.475.3813B. doi:10.1093/mnras/sty034.
  9. "gam Dor". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-11-16.
  10. Kaler, James B. "Gamma Dor". Stars. Retrieved 2020-11-16.
  11. Eggen, Olin J. (December 1995). "Reality Tests of Superclusters in the Young Disk Population". Astronomical Journal. 110: 2862. Bibcode:1995AJ....110.2862E. doi:10.1086/117734.
  12. Balona, L. A.; Krisciunas, K.; Cousins, A. W. J. (October 15, 1994). "γ Doradus: evidence for a new class of pulsating star". Monthly Notices of the Royal Astronomical Society. 270 (4): 905–913. Bibcode:1994MNRAS.270..905B.
  13. Broekhoven-Fiene, Hannah; et al. (January 2013). "The Debris Disk around γ Doradus Resolved with Herschel". The Astrophysical Journal. 762 (1): 11. arXiv:1212.1450. Bibcode:2013ApJ...762...52B. doi:10.1088/0004-637X/762/1/52. 52.
  14. Greaves, J. S.; et al. (February 2014). "Alignment in star-debris disc systems seen by Herschel". Monthly Notices of the Royal Astronomical Society: Letters. 438 (1): L31–L35. arXiv:1310.6936. Bibcode:2014MNRAS.438L..31G. doi:10.1093/mnrasl/slt153.
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