HR 6594

HR 6594 is the Bright Star Catalogue designation for a binary star[11] system in the northern constellation of Hercules. It is faintly visible to the naked eye with an apparent visual magnitude of 5.55;[2] according to the Bortle scale, it is sufficiently bright to be visible from dark suburban skies. The distance to this system, as determined using parallax measurements,[1] is about 114 light years. On the celestial sphere it is located near the star Alpha Ophiuchi; their projected separation is just 3 light years, although their actual separation is much greater.[12]

HR 6594
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules
Right ascension 17h 41m 58.63355s[1]
Declination +15° 57′ 08.7606″[1]
Apparent magnitude (V) 5.55[2]
Characteristics
Evolutionary stage Main sequence[3]
Spectral type F4 Vw[4]
U−B color index −0.05[2]
B−V color index +0.38[2]
Astrometry
Radial velocity (Rv)−43.7[5] km/s
Proper motion (μ) RA: −7.71[1] mas/yr
Dec.: +104.64[1] mas/yr
Parallax (π)28.69 ± 0.63[1] mas
Distance114 ± 2 ly
(34.9 ± 0.8 pc)
Absolute magnitude (MV)2.74[6]
Details
HR 6594 A
Mass1.34[7] M☉
Radius0.97[8] R☉
Surface gravity (log g)4.07[3] cgs
Temperature6,615[3] K
Metallicity [Fe/H]−0.04[9] dex
Rotational velocity (v sin i)31.7[3] km/s
Age1.2[7] Gyr
Other designations
BD-16° 3256, HD 160910, HIP 86623, HR 6594, SAO 103033.[10]
Database references
SIMBADdata

The primary is an F-type main sequence star with a stellar classification of F4 Vw, where the w indicates relatively weak metallic features in the ultraviolet spectrum.[4] This star has 134% of the Sun's mass,[7] but only 97% of the solar radius.[8] It is spinning with a projected rotational velocity of 31.7 km/s,[3] and is around 1.2 billion years old.[7] The effective temperature of the outer atmosphere is 6,615 K,[3] giving it the yellow-white hue of an F-type star.[13] The abundance of elements other than hydrogen or helium, what astronomers term the metallicity, is similar to that in the Sun.[9]

It has a magnitude 9.38 companion star orbiting with a 144-year period, a semimajor axis spanning 1.04 arcseconds, and an eccentricity of 0.42.[11] There is a third, visual companion of magnitude 14.46 at an angular separation of 154.70 arcseconds along a position angle of 271°, as of 2001.[14]

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. Mermilliod, J.-C. (1986), Compilation of Eggen's UBV data, transformed to UBV (unpublished), SIMBAD, Bibcode:1986EgUBV........0M.
  3. Schröder, C.; et al. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo" (PDF), Astronomy and Astrophysics, 493 (3): 1099–1107, Bibcode:2009A&A...493.1099S, doi:10.1051/0004-6361:200810377.
  4. Barry, Don C. (1970), "Spectral Classification of A and F Stars", Astrophysical Journal Supplement, 19: 281, Bibcode:1970ApJS...19..281B, doi:10.1086/190209.
  5. Wilson, R. E. (1953), General Catalogue of Stellar Radial Velocities, Carnegie Institute of Washington D.C., Bibcode:1953GCRV..C......0W.
  6. Boesgaard, A. M.; Tripicco, M. J. (April 15, 1986), "Lithium in early F dwarfs", Astrophysical Journal, Part 1, 303: 724–739, Bibcode:1986ApJ...303..724B, doi:10.1086/164120.
  7. David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146.
  8. Pasinetti-Fracassini, L. E.; et al. (February 2001), "Catalogue of Stellar Diameters (CADARS)", Astronomy and Astrophysics, 367: 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
  9. Casagrande, L.; et al. (2011), "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey", Astronomy & Astrophysics, 530 (A138): 21, arXiv:1103.4651, Bibcode:2011A&A...530A.138C, doi:10.1051/0004-6361/201016276.
  10. "HR 6594". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-09-12.
  11. Malkov, O. Yu.; et al. (October 2012), "Dynamical masses of a selected sample of orbital binaries", Astronomy & Astrophysics, 546: 5, Bibcode:2012A&A...546A..69M, doi:10.1051/0004-6361/201219774, A69.
  12. Redfield, Seth; et al. (June 2007), "Spitzer Limits on Dust Emission and Optical Gas Absorption Variability around Nearby Stars with Edge-on Circumstellar Disk Signatures", The Astrophysical Journal, 661 (2): 944–971, arXiv:astro-ph/0703089, Bibcode:2007ApJ...661..944R, doi:10.1086/517516.
  13. "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on March 10, 2012, retrieved 2012-01-16.
  14. Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122: 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22.
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