HD 195564

HD 195564
Observation data; Epoch J2000.0 Equinox ICRS
Constellation	Capricornus
Right ascension	20h 32m 23.695s
Declination	−09° 51′ 12.18″
Apparent magnitude (V)	5.65
Characteristics
Evolutionary stage	subgiant
Spectral type	G2.5IV
U−B color index	+0.20
B−V color index	+0.68
Astrometry
Radial velocity (Rv)	+9.58 km/s
Proper motion (μ)	RA: +309.736 mas/yr ; Dec.: +109.910 mas/yr
Parallax (π)	40.4241±0.0497 mas
Distance	80.68 ± 0.10 ly ; (24.74 ± 0.03 pc)
Absolute magnitude (MV)	+3.72
Orbit
Primary	620+300; −170 years
Semi-major axis (a)	88+26; −17 au
Eccentricity (e)	0.917+0.037; −0.064
Inclination (i)	64.3+5.7; −6.0°
Details
HD 195564 A
Mass	1.242+0.062; −0.060 M☉
Radius	1.894±0.080 R☉
Luminosity	2.986±0.018 L☉
Surface gravity (log g)	3.95±0.05 cgs
Temperature	5,514±116 K
Metallicity [Fe/H]	0.05±0.02 dex
Rotational velocity (v sin i)	1.91 km/s
Age	8.2 Gyr
HD 195564 B
Mass	0.520+0.027; −0.026 M☉
Other designations
	BD−10°5423, FK5 1536, GJ 792.1, HD 195564, HIP 101345, HR 7845, SAO 163665
Database references
SIMBAD	data
ARICNS	data

HD 195564 is a binary star in the southern constellation of Capricornus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.65. Parallax measurements give us an estimate of its distance as 81 light years.

Based upon the spectrum of light emitted by the primary, it has a stellar classification of G2.5IV. This indicates that it is a G-type subgiant that has exhausted the hydrogen in its core region. It has a mass of 1.242 times the mass of the Sun, but a measured radius that is 1.894 times as large. As a result, it shines with 2.986 times the luminosity of the Sun. 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. The effective temperature of the stellar atmosphere is 5,514 K, giving it the yellow-hued glow of an ordinary K-type star.

The secondary companion has an apparent magnitude of 11.30, and a mass just 55% that of the Sun. The pair orbit each other with an estimated period of around 620 years, following a highly-eccentric path.

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

The HD 195564 planetary system
Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination (°)	Radius
b (unconfirmed)	—	—	5403±164	—	—	—

References

1 2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
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.
1 2 Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins Catalog of Revised MK Types for the Cooler Stars". The Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
↑ 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.
1 2 3 4 5 An, Qier; Brandt, Timothy D.; Brandt, G. Mirek; Venner, Alexander (October 2025), "Orbits and Masses for 156 Companions from Combined Astrometry and Radial Velocities, and a Validation of Gaia Non-single-star Solutions", The Astrophysical Journal Supplement Series, 280 (2): 61, arXiv:2508.08374, Bibcode:2025ApJS..280...61A, doi:10.3847/1538-4365/adfa99, ISSN 0067-0049.
1 2 3 4 5 6 7 8 Soubiran, C.; Creevey, O. L.; Lagarde, N.; Brouillet, N.; Jofré, P.; Casamiquela, L.; Heiter, U.; Aguilera-Gómez, C.; Vitali, S.; Worley, C.; de Brito Silva, D. (2024-02-01). "Gaia FGK benchmark stars: Fundamental Teff and log g of the third version". Astronomy and Astrophysics. 682: A145. arXiv:2310.11302. Bibcode:2024A&A...682A.145S. doi:10.1051/0004-6361/202347136. ISSN 0004-6361. S2CID 264172605.
↑ 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", Astronomy and Astrophysics, 520: A79, arXiv:1002.4391, Bibcode:2010A&A...520A..79M, doi:10.1051/0004-6361/200913725, S2CID 43455849.
1 2 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.
↑ "HD 195564". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved March 15, 2016.
↑ "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.
↑ 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.
↑ 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.
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.

[xhip-1] 1 2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.

[GaiaDR3-2] 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.

[MERMILLIOD-3] 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.

[perkins-4] 1 2 Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins Catalog of Revised MK Types for the Cooler Stars". The Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.

[Nidever2002-5] 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.

[An2025-6] 1 2 3 4 5 An, Qier; Brandt, Timothy D.; Brandt, G. Mirek; Venner, Alexander (October 2025), "Orbits and Masses for 156 Companions from Combined Astrometry and Radial Velocities, and a Validation of Gaia Non-single-star Solutions", The Astrophysical Journal Supplement Series, 280 (2): 61, arXiv:2508.08374, Bibcode:2025ApJS..280...61A, doi:10.3847/1538-4365/adfa99, ISSN 0067-0049.

[soubiran-7] 1 2 3 4 5 6 7 8 Soubiran, C.; Creevey, O. L.; Lagarde, N.; Brouillet, N.; Jofré, P.; Casamiquela, L.; Heiter, U.; Aguilera-Gómez, C.; Vitali, S.; Worley, C.; de Brito Silva, D. (2024-02-01). "Gaia FGK benchmark stars: Fundamental Teff and log g of the third version". Astronomy and Astrophysics. 682: A145. arXiv:2310.11302. Bibcode:2024A&A...682A.145S. doi:10.1051/0004-6361/202347136. ISSN 0004-6361. S2CID 264172605.

[MartínezArnáiz2010-8] 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", Astronomy and Astrophysics, 520: A79, arXiv:1002.4391, Bibcode:2010A&A...520A..79M, doi:10.1051/0004-6361/200913725, S2CID 43455849.

[apj771_1_40-9] 1 2 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.

[SIMBAD-10] "HD 195564". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved March 15, 2016.

[csiro-11] "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.

[WDSC2014-12] 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.

[aj147_4_87-13] 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.

[Butler2017-14] 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.