HD 196885
  | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Delphinus |
| Right ascension | 20h 39m 51.87484s |
| Declination | +11° 14′ 58.7002″ |
| Apparent magnitude (V) | 6.39 |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | F8V + M1±1V |
| B−V color index | 0.559±0.006 |
| Astrometry | |
| Radial velocity (Rv) | −30.13±0.09 km/s |
| Proper motion (μ) | RA: +71.915 mas/yr Dec.: +89.318 mas/yr |
| Parallax (π) | 29.4076±0.0272 mas |
| Distance | 110.9 ± 0.1 ly (34.00 ± 0.03 pc) |
| Absolute magnitude (MV) | 3.76 |
| Orbit: 7 | |
| Primary | HD 196885 A |
| Secondary | HD 196886 B |
| Period (P) | 69.045+0.533 −0.111 yr |
| Semi-major axis (a) | 19.778+0.108 −0.019 AU |
| Eccentricity (e) | 0.417+0.001 −0.004 |
| Inclination (i) | 120.427° |
| Longitude of the node (Ω) | 79.150° |
| Periastron epoch (T) | 1982.886 AD |
| Argument of periastron (ω) (secondary) | 231.464° |
| Details | |
| A | |
| Mass | 1.3±0.1 M☉ |
| Radius | 1.38±0.01 R☉ |
| Luminosity | 2.611±0.007 L☉ |
| Surface gravity (log g) | 4.28±0.03 cgs |
| Temperature | 6,267+18 −16 K |
| Metallicity [Fe/H] | +0.29±0.05 dex |
| Rotation | 15 days |
| Rotational velocity (v sin i) | 7.3±1.5 km/s |
| Age | 1.5—3.5 Gyr |
| B | |
| Mass | 0.45±0.01 M☉ |
| Radius | 0.57±0.04 R☉ |
| Surface gravity (log g) | 4.58±0.06 cgs |
| Temperature | 3,549+121 −124 K |
| Other designations | |
| BD+10°4351, GC 28784, HD 196885, HIP 101966, HR 7907, SAO 106360, WDS J20399+1115, GCRV 12946, GSC 01092-01778, 2MASS J20395188+1114588 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 196885 is a binary star system in the northern constellation of Delphinus. It comprises a pair of stars, HD 196885 A and HD 196885 B, on a 69-year eccentric orbit. The primary star has one known planet.
Stellar properties
The primary star is near the lower limit of visibility to the naked eye with an apparent visual magnitude of 6.39. It is located at a distance of 110.9 light-years from the Sun. It is drifting closer with a radial velocity of −30 km/s, and is expected to come to within 52.5 light-years in 836,000 years.
The secondary, component B, is a red dwarf star separated by 0.6 arcseconds from the primary star that was discovered in 2006 with NaCo at VLT. It has a class in the range M1V to M3V with 51% of the Sun's mass.
The star BD+10 4351B, located 192 arcseconds away from HD 196885, was once thought to be a possible third component of the system, but Gaia astrometry shows a smaller parallax, indicating that it is an unrelated background star.
Planetary system
In 2004, an exoplanet, HD 196885 Ab, was announced to be orbiting the star HD 196885 A in a 386-day orbit. Follow-up work published in 2008 did not confirm the original candidate but instead found evidence of a planet in a 3.63 years orbit. Perturbation by the secondary star in this system may have driven the planet into a high inclination orbit. The planetary existence was confirmed and parameters were refined by 2022.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| b | 3.394+0.702 −0.264 MJ |
2.383+0.002 −0.004 |
3.485+0.001 −0.016 |
0.444+0.013 −0.005 |
143.041+6.572 −4.582 |
— |
See also
References
- 1 2 3 4 5 6 7 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.
- 1 2 3 4 5 6 7 8 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.
- ↑ Gray, R. O.; et al. (2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars", The Astronomical Journal, 121 (4): 2148, Bibcode:2001AJ....121.2148G, doi:10.1086/319956, S2CID 117076031
- 1 2 3 Chauvin, G.; et al. (2007). "Characterization of the long-period companions of the exoplanet host stars: HD 196885, HD 1237 and HD 27442". Astronomy and Astrophysics. 475 (2): 723–727. arXiv:0710.5918. Bibcode:2007A&A...475..723C. doi:10.1051/0004-6361:20067046. S2CID 16950822.
- 1 2 3 4 5 6 7 8 9 Chauvin, G.; Videla, M.; et al. (July 2023). "Chasing extreme planetary architectures. I. HD 196885 Ab, a super-Jupiter dancing with two stars?". Astronomy & Astrophysics. 675: A114. arXiv:2211.00994. Bibcode:2023A&A...675A.114C. doi:10.1051/0004-6361/202244502.
- 1 2 3 4 5 6 Kammerer, J.; Winterhalder, T. O.; Lacour, S.; Stolker, T.; Marleau, G.-D.; Balmer, W. O.; Moore, A. F.; Piscarreta, L.; Toci, C.; Mérand, A.; Nowak, M.; Rickman, E. L.; Pueyo, L.; Pourré, N.; Nasedkin, E. (2025-12-01). "The ExoGRAVITY survey: A K-band spectral library of giant exoplanet and brown dwarf companions". Astronomy & Astrophysics. 704: A318. arXiv:2510.08691. doi:10.1051/0004-6361/202556860. ISSN 0004-6361.
- 1 2 3 Correia, A. C. M.; et al. (2008). "The ELODIE survey for northern extra-solar planets. IV. HD 196885, a close binary star with a 3.7-year planet". Astronomy and Astrophysics. 479 (1): 271–275. arXiv:0711.3343. Bibcode:2008A&A...479..271C. doi:10.1051/0004-6361:20078908. S2CID 119261807.
- ↑ "HD 196885". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-08-08.
- ↑ Chauvin, G.; et al. (2006). "Probing long-period companions to planetary hosts. VLT and CFHT near infrared coronographic imaging surveys". Astronomy and Astrophysics. 456 (3): 1165–1172. arXiv:astro-ph/0606166. Bibcode:2006A&A...456.1165C. doi:10.1051/0004-6361:20054709. S2CID 15611548.
- ↑ "HD 196885 A page". Geneva Observatory. Archived from the original on 2008-05-09. Retrieved 2008-08-19.
- ↑ "TYC 1096-637-1". SIMBAD. Centre de données astronomiques de Strasbourg.
- ↑ "The Planet Around HD 196885". California & Carnegie Planet Search Team (Internet Archive link). Archived from the original on 2004-12-27. Retrieved 2008-08-19.
- ↑ Satyal, S.; Hinse, T. C.; Quarles, B.; Noyola, J. P. (September 2014). "Chaotic dynamics of the planet in HD 196885 AB". Monthly Notices of the Royal Astronomical Society. 443 (2): 1310–1318. arXiv:1401.1268. Bibcode:2014MNRAS.443.1310S. doi:10.1093/mnras/stu1221. S2CID 119189415.
