HR 4458

HR 4458

Observation data Epoch J2000      Equinox J2000
Constellation	Hydra
Right ascension	11^h 34^m 29.487^s[1]
Declination	–32° 49′ 52.82″[1]
Apparent magnitude (V)	5.97[2]/15
Characteristics
Spectral type	K0 V[3] + DC8[4]
U−B color index	0.325[2]
B−V color index	0.80[2]
V−R color index	0.44
R−I color index	0.40
Astrometry
Radial velocity (Rv)	–22.21[5] km/s
Proper motion (μ)	RA: –671.54[6] mas/yr Dec.: 823.85[6] mas/yr
Parallax (π)	104.61 ± 0.37[6] mas
Distance	31.2 ± 0.1 ly (9.56 ± 0.03 pc)
Details
HR 4458 A
Radius	0.84[7] R☉
Luminosity (bolometric)	0.368[8] L☉
Surface gravity (log g)	4.59[9] cgs
Temperature	5,241[9] K
Metallicity [Fe/H]	–0.37[9] dex
Rotational velocity (v sin i)	6.79[10] km/s
Age	4.6–5.8[11] Gyr
Other designations
289 G. Hydrae, CD -32°8179, GCTP 2678.00, GJ 432, HD 100623, HIP 56452, LHS 308, LTT 4280, SAO 202583.
WD 1132-325: VB 04
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, it is the closest star system to the solar system within this constellation. The primary is K-type main-sequence star of class K0. It has a common proper motion companion at an angular separation of 16.2″. This is a white dwarf star with a classification of DC8.^[4]

The primary has been examined for the presence of an infrared excess, but none was detected.^[8]

References

1. Zacharias, N.; et al. (2013). "The Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)". The Astronomical Journal 145 (2). 44. arXiv:1212.6182. Bibcode:2013AJ....145...44Z. doi:10.1088/0004-6256/145/2/44.Vizier catalog entry
2. Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV data. Bibcode:1986EgUBV........0M.
3. Gray, R. O.; et al. (2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal 132 (1): 161–70. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637.
4. Holberg, J. B.; et al. (November 2013). "Where are all the Sirius-like binary systems?". Monthly Notices of the Royal Astronomical Society 435 (3): 2077–2091. arXiv:1307.8047. Bibcode:2013MNRAS.435.2077H. doi:10.1093/mnras/stt1433.
5. Nidever, David L.; et al. (August 2002). "Radial Velocities for 889 Late-Type Stars". The Astrophysical Journal Supplement Series 141 (2): 503–522. arXiv:astro-ph/0112477. Bibcode:2002ApJS..141..503N. doi:10.1086/340570.
6. van Leeuwen, F. (2007). "Validation of the New Hipparcos Reduction". Astronomy and Astrophysics 474 (2): 653–64. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
7. 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.
8. Eiroa, C.; et al. (July 2013). "DUst around NEarby Stars. The survey observational results". Astronomy & Astrophysics 555: A11. arXiv:1305.0155. Bibcode:2013A&A...555A..11E. doi:10.1051/0004-6361/201321050.
9. Ramírez, I.; et al. (September 2012). "Lithium Abundances in nearby FGK Dwarf and Subgiant Stars: Internal Destruction, Galactic Chemical Evolution, and Exoplanets". The Astrophysical Journal 756 (1): 46. arXiv:1207.0499. Bibcode:2012ApJ...756...46R. doi:10.1088/0004-637X/756/1/46.
10. Martínez-Arnáiz, R.; et al. (September 2010). "Chromospheric activity and rotation of FGK stars in the solar vicinity. An estimation of the radial velocity jitter". Astronomy and Astrophysics 520: A79. arXiv:1002.4391. Bibcode:2010A&A...520A..79M. doi:10.1051/0004-6361/200913725.
11. 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.

External links

• "CD-32 8179 / HR 4458 AB". SolStation. Retrieved 2007-06-06.