HD 895 is a multiple star system in the constellation Andromeda. Its apparent magnitude is 6.277,[2] so it can be seen by the naked eye under very favourable conditions. Based on parallax measured by Hipparcos, the system is located around 54 parsecs (180 ly) away,[4] and it is made of two different spectroscopic binary pairs.[5]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | 00h 13m 23.9130s[1] |
| Declination | +26° 59′ 14.9814″[1] |
| Apparent magnitude (V) | 6.277[2] |
| Characteristics | |
| Spectral type | G0III+F2IV[3] |
| B−V color index | 0.63[2] |
| Astrometry | |
| Radial velocity (Rv) | −5.99±0.18[1] km/s |
| Proper motion (μ) | RA: −11.915±1.179[1] mas/yr Dec.: −22.820±1.161[1] mas/yr |
| Parallax (π) | 18.6899 ± 0.7533 mas[1] |
| Distance | 175 ± 7 ly (54 ± 2 pc) |
| Orbit[3] | |
| Primary | HD 895A |
| Companion | HD 895B |
| Period (P) | 421 yr |
| Semi-major axis (a) | 0.641″ |
| Eccentricity (e) | 0.720 |
| Inclination (i) | 124.10° |
| Longitude of the node (Ω) | 193° |
| Periastron epoch (T) | JD 2,401,969.97 |
| Argument of periastron (ω) (secondary) | 286.1° |
| Details[3] | |
| HD 895A | |
| Mass | 2.42 M☉ |
| HD 895B | |
| Mass | 1.92 M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Database references | |
| SIMBAD | data |
The first pair is made of a primary yellow giant star of spectral type G0III, and the secondary subgiant star of spectral type K2IV, so they have both left the main sequence evolutionary phase. They are also both more massive than the Sun. The secondary completes an orbit around the primary every 421 years.[3]
The second pair is a double-lined spectroscopic binary located 18 arcseconds away from the first pair, although with an apparent magnitude of 10.37 it is too faint to be seen without a telescope. It was not recognized as a separate pair in the old Bright Star Catalogue and Henry Draper Catalogue, thus it bears the designation HD 895C. They are both G-type main sequence stars slightly less massive than the Sun, with spectral types G7V and G8V respectively. They complete an orbit around their center of mass approximately every 6 days.[3]
Using Gaia parallax, instead, the pair formed by the primary and the secondary is much closer than previous measures, at an estimated distance of 175 light years. The two pairs, then, may be not gravitationally bound.[1]
References edit
- ^ a b c d e f g Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy & Astrophysics, 355: L27–L30, Bibcode:2000A&A...355L..27H.
- ^ a b c d e Database entry, VizieR Online Data Catalog: Updated Multiple Star Catalog (MSC) (Tokovinin 2018), A. Tokovinin, CDS ID J/ApJS/235/6 Accessed on line 2018-11-29.
- ^ Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
- ^ Tokovinin, A. A. (May 1998). "New Spectroscopic Components in Six Multiple Systems". Astronomy Letters. 24 (3): 288–295. Bibcode:1998AstL...24..288T.
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