HD 181655
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lyra[1] |
| Right ascension | 19h 19m 38.9987s[2] |
| Declination | +37° 19′ 49.946″[2] |
| Apparent magnitude (V) | +6.29[1] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | G5V + G5V[3] |
| B−V color index | 0.676±0.003[1] |
| Astrometry | |
| Radial velocity (Rv) | +1.827±0.031[3] km/s |
| Proper motion (μ) | RA: −61.4 mas/yr[2] Dec.: −183.7 mas/yr[2] |
| Parallax (π) | 41.08±0.77 mas[3] |
| Distance | 79.4 ± 1.5 ly (24.34±0.45 pc)[3] |
| Absolute magnitude (MV) | +4.27[1] |
| Orbit[3] | |
| Period (P) | 331.609±0.0037 days |
| Semi-major axis (a) | (47.432±0.035)×10−3" (1.156 au) |
| Eccentricity (e) | 0.9322±0.00013 |
| Inclination (i) | 29.48±0.86° |
| Longitude of the node (Ω) | 181.046±0.092° |
| Periastron epoch (T) | 58,142.690±0.0027 HJD |
| Argument of periastron (ω) (secondary) | 169.888±0.075° |
| Semi-amplitude (K1) (primary) | 25.555±0.047 km/s |
| Semi-amplitude (K2) (secondary) | 25.947±0.048 km/s |
| Details[3] | |
| A | |
| Mass | 0.941±0.076 M☉ |
| Radius | 0.95 R☉ |
| Rotational velocity (v sin i) | 2.6±1.0 km/s |
| B | |
| Mass | 0.926±0.075 M☉ |
| Radius | 0.95 R☉ |
| Rotational velocity (v sin i) | 2.6±1.0 km/s |
| Other designations | |
| BD+37°3417, GJ 754.2, GJ 9654, HD 181655, HIP 94981, HR 7345, TYC 2665-2093-1[4] | |
| Database references | |
| SIMBAD | data |
HD 181655 (HR 7345) is a binary star in the constellation Lyra. At an apparent magnitude of +6.29, it is very faintly visible to the naked eye in locations far from light pollution. Dynamical parallax measurements give a distance of 79.4 light-years (24.34 parsecs) light-years.
Characteristics
[edit]This is a spectroscopic binary system with an orbital period of 331.609 days, a semi-major axis of 1.156 astronomical units and a very high orbital eccentricity of 0.9322, bringing the stars to 0.079 au at periastron. The source of such a high eccentricity may be a red dwarf separated by 35" from the inner pair, which excited the binary's eccentricity through the Kozai mechanism. The large eccentricity also hinders the spectral lines of both stars to be seen for most of the orbital path, so the system alternates between a single-lined and a double-lined spectroscopic binary. The double-line phase is observable for only 15 days per orbit.[3]
The two components are similar to each other, each with a spectral type of G5V.[1] The primary has a mass of 0.94 solar masses and the secondary has 0.93 solar masses, give or take 0.08 solar masses.[3]
References
[edit]- ^ a b c d e Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
- ^ a b c Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d e f g h i Farrington, C. D.; Fekel, Francis C.; Schaefer, G. H.; ten Brummelaar, T. A. (October 2018). "Separated Fringe Packet Observations with the CHARA Array. III. The Very High-eccentricity Binary HR 7345". The Astronomical Journal. 156 (4): 144. arXiv:1808.07313. Bibcode:2018AJ....156..144F. doi:10.3847/1538-3881/aad869. ISSN 0004-6256.
- ^ "HD 181655". SIMBAD. Centre de données astronomiques de Strasbourg.