HD 2942
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | 00h 32m 49.0863s[1] |
| Declination | +28° 16′ 48.8676″[1] |
| Apparent magnitude (V) | 6.33[2] |
| Characteristics | |
| Spectral type | K0III+G6V+G8V[3] |
| U−B color index | 0.80[2] |
| B−V color index | 0.99[2] |
| Astrometry | |
| Radial velocity (Rv) | −10.50±0.14[1] km/s |
| Proper motion (μ) | RA: −5.695±0.072[1] mas/yr Dec.: 6.101±0.039[1] mas/yr |
| Parallax (π) | 5.8690 ± 0.0434 mas[1] |
| Distance | 556 ± 4 ly (170 ± 1 pc) |
| Orbit[3] | |
| Primary | HD 2942Ba |
| Companion | HD 2942Bb |
| Period (P) | 7.4887 days |
| Eccentricity (e) | 0.055 |
| Periastron epoch (T) | HJD 2,451,060.5586 |
| Argument of periastron (ω) (secondary) | 293.40° |
| Semi-amplitude (K1) (primary) | 64.01 km/s |
| Semi-amplitude (K2) (secondary) | 66.34 km/s |
| Details[3] | |
| HD 2942A | |
| Mass | 3.17 M☉ |
| HD 2942B | |
| Mass | 0.89 (Ba) 0.85 (Bb) M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Database references | |
| SIMBAD | data |
HD 2942 is a triple star system[3] in the constellation Andromeda located approximately 170 parsecs (550 ly) away.
The primary component, a red giant of spectral type K0III, has an apparent magnitude of 6.33, meaning that it is barely visible with the naked eye under good conditions.[2]
The secondary component is much fainter, with an apparent magnitude 11.26, and is located 8.6 arcseconds away. It is a double-lined spectroscopic binary, where two very similar G-type main sequence stars of spectral types G6V and G8V orbit around their common center of mass in 7.489 days. The pair complete an orbit around the primary star every 24,762 years.[3]
Catalogues of stellar multiplicity, like the Washington Double Star Catalog, usually list another component; this star, however, is located much more far away than the other two.[4]
References
[edit]- ^ a b c d e f 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 d Database entry, Catalogue of Stellar Photometry in Johnson's 11-color system (2002 Ed.), J. R. Ducati, CDS ID II/237 Accessed on line 2018-12-05.
- ^ 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.
- ^ "ADS 455 C". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved December 6, 2018.
External links
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