| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Delphinus |
| Right ascension | 20h 39m 51.87531s [1] |
| Declination | +11° 14′ 58.7029″ [1] |
| Apparent magnitude (V) | 6.39 [2] |
| Characteristics | |
| Evolutionary stage | main-sequence star |
| Spectral type | F8V [3] + M1±1V [4] |
| B−V color index | 0.559±0.006 [2] |
| Astrometry | |
| Radial velocity (Rv) | −30.13±0.09 [2] km/s |
| Proper motion (μ) |
RA: +71.470±0.066
[1]
mas/
yr Dec.: +89.165±0.076 [1] mas/ yr |
| Parallax (π) | 29.4076 ± 0.0272 mas [5] |
| Distance | 110.9 ± 0.1
ly (34.00 ± 0.03 pc) |
| Absolute magnitude (MV) | 3.76 [2] |
| Orbit [6] | |
| Primary | HD 196885 A |
| Companion | HD 196886 B |
| Period (P) | 69.045 yr |
| Semi-major axis (a) | 19.778 AU |
| Eccentricity (e) | 69.045 |
| 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 [6] | |
| A | |
| Mass | 1.33 M☉ |
| Radius | 1.45+0.02 −0.05 R☉ |
| Luminosity | 2.695±0.006 [1] L☉ |
| Surface gravity (log g) | 4.46±0.02 cgs |
| Temperature | 6,340±39 K |
| Metallicity [Fe/H] | 0.29±0.05 dex |
| Rotation | 15 days |
| Rotational velocity (v sin i) | 7.3±1.5 km/s |
| Age | 2.0±0.5 Gyr |
| B | |
| Mass | 0.508±0.001 [6] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 196885 is a binary star system in the northern constellation of Delphinus. It comprise a pair of stars HD 196885 A and HD 196885 B on a 69-years eccentric orbit. [6]
The primary star is near the lower limit of visibility to the naked eye with an apparent visual magnitude of 6.39. [2] It is located at a distance of 110.9 light years from the Sun. [5] 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. [2]
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. [8] [4] It has a class in the range M1V to M3V [4] with 51% of the Sun's mass. [6]
The star BD+10 4351B, located 192 arcseconds away from HD 196885 is located at the same distance and may be a physically bound companion star, in which case HD 196885 is a triple system. [9] If it is bound, then the separation is at least 6,600 AU (the separation along the line-of-sight is unknown, so this value represents a lower limit on the true separation).[ citation needed]
Planetary system
In 2004, a planet was announced to be orbiting the star HD 196885 A in a 386-day orbit. [10] Follow-up work published in 2008 did not confirm the original candidate but instead found evidence of a planet in a 3.63 years. [11] Perturbation by the secondary star in this system may have driven the planet into a high inclination orbit. [12] The planetary existence was confirmed and parameters were refined by 2022. [6]
| Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 3.39 MJ | 2.383 | 3.485 | 0.444 | 143.041 ° | — |
See also
References
- ^ a b c d e 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 e f 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. S2CID 119257644.
- ^ 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 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 Chauvin, G.; Videla, M.; Beust, H.; Mendez, R.; Correia, A. C. M.; Lacour, S.; Tokovinin, A.; Hagelberg, J.; Bouchy, F.; Boisse, I.; Villegas, C.; Bonavita, M.; Desidera, S.; Faramaz, V.; Forveille, T.; Gallenne, A.; Haubois, X.; Jenkins, J. S.; Kervella, P.; Lagrange, A. -M.; Melo, C.; Thebault, P.; Udry, S.; Segransan, D. (2023), "Chasing extreme planetary architectures", Astronomy & Astrophysics, 675: A114, arXiv: 2211.00994, doi: 10.1051/0004-6361/202244502
- ^ "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. Retrieved 2008-08-19.
- ^ "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.
- ^ 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.
- ^ 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.
