HD 196885
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Delphinus[1] |
| Right ascension | 20h 39m 51.87484s[2] |
| Declination | +11° 14′ 58.7002″[2] |
| Apparent magnitude (V) | 6.39[1] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | F8V[3] + M1±1V[4] |
| B−V color index | 0.559±0.006[1] |
| Astrometry | |
| Radial velocity (Rv) | −30.13±0.09[1] km/s |
| Proper motion (μ) | RA: +71.915 mas/yr[2] Dec.: +89.318 mas/yr[2] |
| Parallax (π) | 29.4076±0.0272 mas[2] |
| Distance | 110.9 ± 0.1 ly (34.00 ± 0.03 pc) |
| Absolute magnitude (MV) | 3.76[1] |
| Orbit[5]: 7 | |
| Primary | HD 196885 A |
| Name | 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[5] M☉ |
| Radius | 1.38±0.01[6] R☉ |
| Luminosity | 2.611±0.007[2] L☉ |
| Surface gravity (log g) | 4.28±0.03[6] cgs |
| Temperature | 6,267+18 −16[6] K |
| Metallicity [Fe/H] | +0.29±0.05[5] dex |
| Rotation | 15[7] days |
| Rotational velocity (v sin i) | 7.3±1.5[7] km/s |
| Age | 1.5—3.5[5] Gyr |
| B | |
| Mass | 0.45±0.01[5] M☉ |
| Radius | 0.57±0.04[6] R☉ |
| Surface gravity (log g) | 4.58±0.06[6] cgs |
| Temperature | 3,549+121 −124[6] 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[8] | |
| 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.[5]
Stellar properties
The primary star is near the lower limit of visibility to the naked eye with an apparent visual magnitude of 6.39.[1] It is located at a distance of 110.9 light-years from the Sun.[2] 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.[1]
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.[9][4] It has a class in the range M1V to M3V[4] with 51% of the Sun's mass.[5]
The star BD+10 4351B, located 192 arcseconds away from HD 196885, was once thought to be a possible third component of the system,[10] but Gaia astrometry shows a smaller parallax, indicating that it is an unrelated background star.[11]
Planetary system
In 2004, an exoplanet, HD 196885 Ab, was announced to be orbiting the star HD 196885 A in a 386-day orbit.[12] 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.[7] Perturbation by the secondary star in this system may have driven the planet into a high inclination orbit.[13] The planetary existence was confirmed and parameters were refined by 2022.[5]
| 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
- ^ a b c d e f g 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 d e f g 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
- ^ a b c 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.
- ^ a b c d e f g h i 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.
- ^ a b c d e f 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. doi:10.1051/0004-6361/202556860. ISSN 0004-6361.
- ^ a b c 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.