HD 195564
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Capricornus
Right ascension 20h 32m 23.695s[1]
Declination −09° 51′ 12.18″[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: +309.736 mas/yr[1]
Dec.: +109.910 mas/yr[1]
Parallax (π)40.4241 ± 0.0497 mas[1]
Distance80.68 ± 0.10 ly
(24.74 ± 0.03 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

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 give us an estimate of its distance as 81 light years. This is a candidate wide binary system as a faint companion star shares a common proper motion with the brighter primary component.[7]

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]

In a paper published in April 2017, a candidate planet was found orbiting HD 195564 with a period of 5,404 days (14.80 yr).[11]

The HD 195564 planetary system[11]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b (unconfirmed) — — 5403.77251±164.1426 — — —

References

  1. 1 2 3 4 5 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  2. 1 2 3 4 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. 1 2 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, S2CID 119417105.
  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, S2CID 51814894.
  5. 1 2 3 4 5 6 7 8 9 10 11 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, S2CID 14911430, 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, S2CID 43455849, archived from the original (PDF) on 2017-09-22, retrieved 2018-11-04.
  7. 1 2 3 4 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, S2CID 56066740, 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 18, 2012, retrieved 2012-01-16.
  10. 1 2 Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22.
  11. 1 2 Butler, R. Paul; et al. (13 April 2017). "The LCES HIRES/Keck Precision Radial Velocity Exoplanet Survey". The Astronomical Journal. 153 (5): 208. arXiv:1702.03571. Bibcode:2017AJ....153..208B. doi:10.3847/1538-3881/aa66ca. hdl:2299/18220. S2CID 14954371. Planet candidate is in Table 2; full table available here.
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