HR 4458
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| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hydra |
| Right ascension | 11h 34m 29.4871s |
| Declination | −32° 49′ 52.823″ |
| Apparent magnitude (V) | 5.98/15 |
| Characteristics | |
| Spectral type | K0 V / M? V |
| U−B color index | 0.33 |
| B−V color index | 0.80 |
| V−R color index | 0.44 |
| R−I color index | 0.40 |
| Variable type | None |
| Astrometry | |
| Radial velocity (Rv) | -22.6 km/s |
| Proper motion (μ) | RA: -670.99 mas/yr Dec.: 823.89 mas/yr |
| Parallax (π) | 104.84 ± 0.81 mas |
| Distance | 31.1 ± 0.2 ly (9.54 ± 0.07 pc) |
| Absolute magnitude (MV) | 6.09/15 |
| Details | |
| Radius | 0.84/0.15[1] R☉ |
| Surface gravity (log g) | 4.6[2]/– cgs |
| Temperature | 5400[2]/2960[1] K |
| Metallicity | [Fe/H] = -0.26[2] |
| Age | (4.6–5.8) × 109[3] years |
| Other designations | |
289 G. Hydrae, GJ 432, CD -32°8179, HD 100623, LHS 308, LTT 4280, GCTP 2678.00, SAO 202583, HIP 56452. | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
HR 4458 (289 G. Hydrae) is a binary star system in the constellation Hydra. At a distance of 31 light years, they are the closest stars to the solar system within this constellation. The A star is an orange dwarf star of class K0, whereas the B is a small red dwarf. The pair has an angular separation of 16.2″.[4]
References
- ↑ 1.0 1.1 Johnson, H. M. & Wright, C. D. (183). "Predicted infrared brightness of stars within 25 parsecs of the sun". Astrophysical Journal Supplement Series 53 (2): 643–711. Bibcode:1983ApJS...53..643J. doi:10.1086/190905.
- ↑ 2.0 2.1 2.2 Flynn, C.; Morell, O. (1997). "Metallicities and kinematics of G and K dwarfs". Monthly Notices of the Royal Astronomical Society 286 (2): 617–625. arXiv:astro-ph/9609017. Bibcode:1996astro.ph..9017F.
- ↑ Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008). "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics". The Astrophysical Journal 687 (2): 1264–1293. arXiv:0807.1686. Bibcode:2008ApJ...687.1264M. doi:10.1086/591785.
- ↑ Poveda, A.; Herrera, M. A.; Allen, C.; Cordero, G.; Lavalley, C. (1994). "The new astrometry". Revista Mexicana de Astronomia y Astrofisica 28: 43–89. Bibcode:1994RMxAA..28...43P.
External links
- "CD-32 8179 / HR 4458 AB". SolStation. Retrieved 2007-06-06.
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