HD 195564
Star in the constellation Capricornus
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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.[3] 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.[9]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| 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 mas/yr[2] Dec.: +109.910 mas/yr[2] |
| Parallax (π) | 40.4241±0.0497 mas[2] |
| Distance | 80.68 ± 0.10 ly (24.74 ± 0.03 pc) |
| Absolute magnitude (MV) | +3.72[1] |
| Details | |
| HD 195564 A | |
| Mass | 1.097[6] M☉ |
| Radius | 1.867±0.083[6] R☉ |
| Luminosity | 2.705±0.047[6] L☉ |
| Surface gravity (log g) | 3.74[7] cgs |
| Temperature | 5,421±118[6] K |
| Metallicity [Fe/H] | +0.06[6] dex |
| Rotational velocity (v sin i) | 1.91[8] km/s |
| Age | 8.2[6] Gyr |
| HD 195564 B | |
| Mass | 0.55[9] M☉ |
| Other designations | |
| BD−10°5423, FK5 1536, GJ 792.1, HD 195564, HIP 101345, HR 7845, SAO 163665[10] | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
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 an estimated mass of 1.097[6] times the mass of the Sun, but a measured radius that is 1.867 times as large.[6] As a result, it shines with 2.705 times the luminosity of the Sun.[6] 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.[6] The effective temperature of the stellar atmosphere is 5,421 K,[6] 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.[9] As measured in 1965, it had an angular separation of 3.20″ from the primary, along a position angle of 27°[12] The pair orbit each other with an estimated period of around 510 years.[9]
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).[13]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (unconfirmed) | — | — | 5403.77251±164.1426 | — | — | — |