HD 195564

HD 195564 is the Henry Draper Catalogue designation for a star in the southern constellation of Capricornus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.65.[2] Parallax measurements from the Hipparcos spacecraft give us an estimate of its distance as around 80 light years. This appears to be a wide binary system as a faint companion star shares a common proper motion with the brighter primary component.[7]

HD 195564
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Capricornus
Right ascension  20h 32m 23.69559s[1]
Declination −09° 51′ 12.1731″[1]
Apparent magnitude (V) 5.65[2]
Characteristics
Spectral type G2 V[3]
U−B color index +0.20[2]
B−V color index +0.68[2]
Astrometry
Radial velocity (Rv)+9.58[4] km/s
Proper motion (μ) RA: +307.35[1] mas/yr
Dec.: +106.94[1] mas/yr
Parallax (π)40.98 ± 0.33[1] mas
Distance79.6 ± 0.6 ly
(24.4 ± 0.2 pc)
Details
HD 195564 A
Mass1.097[5] M☉
Radius1.867±0.083[5] R☉
Luminosity2.705±0.047[5] L☉
Surface gravity (log g)3.74[3] cgs
Temperature5421±118[5] K
Metallicity [Fe/H]+0.06[5] dex
Rotational velocity (v sin i)1.91[6] km/s
Age8.2[5] Gyr
HD 195564 B
Mass0.55[7] M☉
Other designations
BD−10° 5423, FK5 1536, GJ 792.1, HD 195564, HIP 101345, HR 7845, SAO 163665.[8]
Database references
SIMBADdata
ARICNSdata

Based upon the spectrum of light emitted by the primary, it has a stellar classification of G2 V.[3] This indicates that it is a G-type main sequence star that is generating energy through the process of thermonuclear fusion in its core region. It has an estimated mass of 1.097[5] times the mass of the Sun, but a measured radius that is 1.867 times as large.[5] As a result, it shines with 2.705 times the luminosity of the Sun.[5] The abundance of elements in this star is similar to that in the Sun, although it is an older star with an age of around 8.2 billion years.[5] The effective temperature of the stellar atmosphere is 5,421 K,[5] giving it the yellow-hued glow of an ordinary K-type star.[9]

The secondary companion has an apparent magnitude of 11.30,[10] and a mass just 55% that of the Sun.[7] As measured in 1965, it had an angular separation of 3.20″ from the primary, along a position angle of 27°[10] The pair orbit each other with an estimated period of around 510 years.[7]

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. Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
  3. Gray, R. O.; et al. (2003), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I", The Astronomical Journal, 126 (4): 2048–2059, arXiv:astro-ph/0308182, Bibcode:2003AJ....126.2048G, doi:10.1086/378365.
  4. Nidever, David L.; et al. (August 2002), "Radial Velocities for 889 Late-Type Stars", The Astrophysical Journal Supplement Series, 141 (2): 503–522, arXiv:astro-ph/0112477, Bibcode:2002ApJS..141..503N, doi:10.1086/340570.
  5. Boyajian, Tabetha S.; et al. (July 2013), "Stellar Diameters and Temperatures. III. Main-sequence A, F, G, and K Stars: Additional High-precision Measurements and Empirical Relations", The Astrophysical Journal, 771 (1): 31, arXiv:1306.2974, Bibcode:2013ApJ...771...40B, doi:10.1088/0004-637X/771/1/40, 40. See Table 3.
  6. Martínez-Arnáiz, R.; et al. (September 2010), "Chromospheric activity and rotation of FGK stars in the solar vicinity. An estimation of the radial velocity jitter" (PDF), Astronomy and Astrophysics, 520: A79, arXiv:1002.4391, Bibcode:2010A&A...520A..79M, doi:10.1051/0004-6361/200913725.
  7. Tokovinin, Andrei (April 2014), "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs", The Astronomical Journal, 147 (4): 14, arXiv:1401.6827, Bibcode:2014AJ....147...87T, doi:10.1088/0004-6256/147/4/87, 87.
  8. "HD 195564". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved March 15, 2016.
  9. "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.
  10. 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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