Astronomy:HD 195564
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Capricornus[1] |
| Right ascension | 20h 32m 23.695s[2] |
| Declination | −09° 51′ 12.18″[2] |
| Apparent magnitude (V) | 5.65[3] |
| Characteristics | |
| Evolutionary stage | subgiant[2] |
| Spectral type | G2.5IV[4] |
| U−B color index | +0.20[3] |
| B−V color index | +0.68[3] |
| Astrometry | |
| Radial velocity (Rv) | +9.58[5] km/s |
| Proper motion (μ) | RA: +309.736[2] mas/yr Dec.: +109.910[2] mas/yr |
| Parallax (π) | 40.4241 ± 0.0497[2] mas |
| Distance | 80.68 ± 0.10 ly (24.74 ± 0.03 pc) |
| Absolute magnitude (MV) | +3.72[1] |
| Orbit[6] | |
| Primary | 620+300 −170 |
| 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[6] M☉ |
| Radius | 1.867±0.083[7] R☉ |
| Luminosity | 2.705±0.047[7] L☉ |
| Surface gravity (log g) | 3.74[8] cgs |
| Temperature | 5,421±118[7] K |
| Metallicity [Fe/H] | +0.06[7] dex |
| Rotational velocity (v sin i) | 1.91[9] km/s |
| Age | 8.2[7] Gyr |
| HD 195564 B | |
| Mass | 0.520+0.027 −0.026[6] M☉ |
| Other designations | |
| 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.[3] 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.[4] 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,[6] but a measured radius that is 1.867 times as large.[7] As a result, it shines with 2.705 times the luminosity of the Sun.[7] 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.[7] The effective temperature of the stellar atmosphere is 5,421 K,[7] giving it the yellow-hued glow of an ordinary K-type star.[11]
The secondary companion has an apparent magnitude of 11.30,[12] and a mass just 55% that of the Sun.[13] The pair orbit each other with an estimated period of around 620 years, following a highly-eccentric path.[6]
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).[14]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (unconfirmed) | — | — | 5403±164 | — | — | — |
References
- ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A XHIP record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 3.3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data (SIMBAD), Bibcode: 1986EgUBV........0M.
- ↑ 4.0 4.1 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. doi:10.1086/191373. Bibcode: 1989ApJS...71..245K.
- ↑ Nidever, David L. et al. (August 2002), "Radial Velocities for 889 Late-Type Stars", The Astrophysical Journal Supplement Series 141 (2): 503–522, doi:10.1086/340570, Bibcode: 2002ApJS..141..503N.
- ↑ 6.0 6.1 6.2 6.3 6.4 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" (in en), The Astrophysical Journal Supplement Series 280 (2): 61, doi:10.3847/1538-4365/adfa99, ISSN 0067-0049, Bibcode: 2025ApJS..280...61A.
- ↑ 7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 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, doi:10.1088/0004-637X/771/1/40, 40, Bibcode: 2013ApJ...771...40B. See Table 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, doi:10.1086/378365, Bibcode: 2003AJ....126.2048G.
- ↑ 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, doi:10.1051/0004-6361/200913725, Bibcode: 2010A&A...520A..79M.
- ↑ "HD 195564". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+195564.
- ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16.
- ↑ Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466–3471, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M, http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/wds, 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, doi:10.1088/0004-6256/147/4/87, 87, Bibcode: 2014AJ....147...87T.
- ↑ 14.0 14.1 Butler, R. Paul et al. (13 April 2017). "The LCES HIRES/Keck Precision Radial Velocity Exoplanet Survey". The Astronomical Journal 153 (5): 208. doi:10.3847/1538-3881/aa66ca. Bibcode: 2017AJ....153..208B. Planet candidate is in Table 2; full table available here.
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