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]
| 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] |
| Distance | 80.68 ± 0.10 ly (24.74 ± 0.03 pc) |
| Details | |
| HD 195564 A | |
| Mass | 1.097[5] M☉ |
| Radius | 1.867±0.083[5] R☉ |
| Luminosity | 2.705±0.047[5] L☉ |
| Surface gravity (log g) | 3.74[3] cgs |
| Temperature | 5421±118[5] K |
| Metallicity [Fe/H] | +0.06[5] dex |
| Rotational velocity (v sin i) | 1.91[6] km/s |
| Age | 8.2[5] Gyr |
| HD 195564 B | |
| Mass | 0.55[7] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
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]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (unconfirmed) | — | — | 5403.77251±164.1426 | — | — | — |
References
edit- ^ a b c d 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.
- ^ a b c d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
- ^ a b c 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.
- ^ 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.
- ^ a b c d e f g h i j k 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.
- ^ 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.
- ^ a b c d 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.
- ^ "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.
- ^ a b 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.
- ^ a b 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.