17 Crateris
17 Crateris is a wide binary star[8] system in the equatorial constellation of Hydra, located 90.5 light years away from the Sun. It is visible to the naked eye as a faint, yellow-white hued star with a combined apparent visual magnitude of 4.93.[3] The system is traversing the celestial sphere with a relative proper motion of 24.9 mas/y,[9] and is moving away from the Earth with a heliocentric radial velocity of +5.8 km/s.[4]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hydra |
| 17 Crt A | |
| Right ascension | 11h 32m 16.40436s[1] |
| Declination | −29° 15′ 39.6740″[1] |
| Apparent magnitude (V) | 5.64[2] |
| 17 Crt B | |
| Right ascension | 11h 32m 16.03998s[1] |
| Declination | −29° 15′ 47.8935″[1] |
| Apparent magnitude (V) | 5.76[2] |
| Characteristics | |
| Spectral type | F8V + F8V[2] |
| B−V color index | 0.540±0.004[3] |
| Astrometry | |
| 17 Crt A | |
| Radial velocity (Rv) | +5.8±0.4[4] km/s |
| Proper motion (μ) | RA: −19.601[1] mas/yr Dec.: +144.524[1] mas/yr |
| Parallax (π) | 36.0601 ± 0.1266 mas[1] |
| Distance | 90.4 ± 0.3 ly (27.73 ± 0.10 pc) |
| 17 Crt B | |
| Proper motion (μ) | RA: −22.025[1] mas/yr Dec.: +139.982[1] mas/yr |
| Parallax (π) | 35.9838 ± 0.1320 mas[1] |
| Distance | 90.6 ± 0.3 ly (27.8 ± 0.1 pc) |
| Details[5] | |
| 17 Crt A | |
| Mass | 1.20 M☉ |
| Luminosity | 3.2 L☉ |
| Surface gravity (log g) | 4.17 cgs |
| Temperature | 6,240 K |
| Metallicity [Fe/H] | 0.04±0.15[6] dex |
| Rotational velocity (v sin i) | 10.0 km/s |
| Age | 3.95 Gyr |
| 17 Crt B | |
| Mass | 1.18 M☉ |
| Luminosity | 2.8 L☉ |
| Surface gravity (log g) | 4.20 cgs |
| Temperature | 6,269 K |
| Metallicity [Fe/H] | −0.06±0.15[6] dex |
| Rotational velocity (v sin i) | 9.6 km/s |
| Age | 3.67 Gyr |
| Other designations | |
| 17 Crt A: HD 100287, HR 4444, SAO 179968 | |
| 17 Crt B: HD 100286, HR 4443, SAO 179967 | |
| Database references | |
| SIMBAD | data |
The dual nature of this system was discovered by W. Herschel in 1783, when they showed an angular separation of 9.8″. As of 2015, the two components of this system had a separation of 9.60″ along a position angle of 210°.[10] This is equivalent to a projected separation of 241.3 AU; wide enough that, thus far, their orbital track appears linear.[9] They are nearly identical F-type main-sequence stars with a stellar classification of F8V.[2] The primary is slightly brighter at magnitude 5.64, while the secondary is magnitude 5.76.[2]
References
- 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.
- 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.
- 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.
- Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
- Luck, R. Earle (January 2017), "Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants", The Astronomical Journal, 153 (1): 19, arXiv:1611.02897, Bibcode:2017AJ....153...21L, doi:10.3847/1538-3881/153/1/21, S2CID 119511744, 21.
- Gáspár, András; et al. (2016), "The Correlation between Metallicity and Debris Disk Mass", The Astrophysical Journal, 826 (2): 171, arXiv:1604.07403, Bibcode:2016ApJ...826..171G, doi:10.3847/0004-637x/826/2/171, S2CID 119241004.
- "17 Crt". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved May 4, 2019.
- Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- Tokovinin, A.; Kiyaeva, O. (February 2016), "Eccentricity distribution of wide binaries", Monthly Notices of the Royal Astronomical Society, 456 (2): 2070−2079, arXiv:1512.00278, Bibcode:2016MNRAS.456.2070T, doi:10.1093/mnras/stv2825.
- Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22.