HD 104304

HD 104304 (24 G. Virginis) is a binary star in the zodiac constellation Virgo. It has an apparent magnitude of 5.54, making it visible to the unaided eye under suitable viewing conditions. The stellar classification of G8 IV means that this is a subgiant star that has left the main sequence and has begun to evolve into a giant star.

HD 104304
Observation data
Epoch J2000      Equinox J2000
Constellation Virgo
Right ascension  12h 00m 44.45136s[1]
Declination –10° 26′ 45.6527″[1]
Apparent magnitude (V) 5.54[2]
Characteristics
Spectral type G8 IV[3] / M4V[4]
U−B color index +0.43[2]
B−V color index +0.76[2]
Astrometry
Radial velocity (Rv)0.4 km/s
Proper motion (μ) RA: 141.75[1] mas/yr
Dec.: -483.64[1] mas/yr
Parallax (π)78.35 ± 0.31[1] mas
Distance41.6 ± 0.2 ly
(12.76 ± 0.05 pc)
Absolute magnitude (MV)5.15±0.009[5]
Orbit[4]
Period (P)48.5 yr
Semi-major axis (a)10.4 AU
Eccentricity (e)0.29
Inclination (i)35°
Details
A
Mass0.98[6] M☉
Radius1.01[6] R☉
Surface gravity (log g)4.43[6] cgs
Temperature5538[3] K
Metallicity [Fe/H]0.18[7] dex
Rotational velocity (v sin i)4.5[8] km/s
Age8.48[6] Gyr
B
Mass0.21+0.03
−0.02[4] M☉
Other designations
24 G. Virginis, GJ 454, BD-09°3413, LTT 4476, HR 4587, SAO 157041, HIP 58576.
Database references
SIMBADdata

In 2007, a candidate planet was announced orbiting this star. This was updated in 2010 when two independent papers announced the discovery of a common proper motion companion red dwarf.[4][9] It is believed to have a mass of 0.21 M☉ and spectral type of M4V although the spectrum has not been directly observed. The most likely orbit has a period of 48.5 years and an eccentricity of 0.29.[4][10] Further measurement will be needed to determine whether the star has a planetary companion, but further companions with masses above 83 MJ and separated by at least 3.9 au can be ruled out.[4]

References
  1. van Leeuwen, F. (November 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. Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J
  3. Gray, R. O.; et al. (July 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
  4. Schnupp, C.; et al. (June 2010), "Discovery of a stellar companion to the nearby solar-analogue HD 104304", Astronomy and Astrophysics, 516: A21, arXiv:1005.0620, Bibcode:2010A&A...516A..21S, doi:10.1051/0004-6361/201014740
  5. Park, Sunkyung; et al. (2013), "Wilson-Bappu Effect: Extended to Surface Gravity", The Astronomical Journal, 146 (4): 73, arXiv:1307.0592, Bibcode:2013AJ....146...73P, doi:10.1088/0004-6256/146/4/73.
  6. Takeda, Genya; Ford, Eric B; Sills, Alison; Rasio, Frederic A; Fischer, Debra A; Valenti, Jeff A (2007). "Structure and Evolution of Nearby Stars with Planets. II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog". The Astrophysical Journal Supplement Series. 168 (2): 297. arXiv:astro-ph/0607235. Bibcode:2007ApJS..168..297T. doi:10.1086/509763.
  7. Hearnshaw, J. B. (1972), "The abundances of the elements in the oldest disk stars", Memoirs of the Royal Astronomical Society, 77: 55, Bibcode:1972MmRAS..77...55H
  8. Schröder, C.; Reiners, A.; Schmitt, J. H. M. M. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo", Astronomy and Astrophysics, 493 (3): 1099–1107, Bibcode:2009A&A...493.1099S, doi:10.1051/0004-6361:200810377
  9. Tanner, Angelle M; Gelino, Christopher R; Law, Nicholas M (2010). "A High-Contrast Imaging Survey of SIM Lite Planet Search Targets". Publications of the Astronomical Society of the Pacific. 122 (896): 1195. arXiv:1007.4315. Bibcode:2010PASP..122.1195T. doi:10.1086/656481.
  10. Schneider, Jean, "Star : HD 104304", Extrasolar Planets Encyclopaedia, CNRS/LUTH - Paris Observatory, retrieved 2011-12-21
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