Astronomy:HR 4458
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Hydra |
| Right ascension | 11h 34m 29.48628s[1] |
| Declination | –32° 49′ 52.8199″[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: –670.120[1] mas/yr Dec.: +822.228[1] mas/yr |
| Parallax (π) | 104.7828 ± 0.0518[1] mas |
| Distance | 31.13 ± 0.02 ly (9.544 ± 0.005 pc) |
| Absolute magnitude (MV) | 6.05[6] |
| 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 | |
| WD 1132-325: VB 04 | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
HR 4458 is a binary star system in the equatorial constellation of Hydra. It has the Gould designation 289 G. Hydrae; HR 4458 is the Bright Star Catalogue designation. At a distance of 31.13 light years, it is the closest star system to the Solar System within this constellation. This object is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.97.[2] It is moving closer to the Earth with a heliocentric radial velocity of −22 km/s.[5]
The primary component is K-type main-sequence star with a stellar classification of K0 V.[3] It is around five[11] billion years old with 84%[7] of the Sun's radius. The star is radiating 37%[8] of the Sun's luminosity from its photosphere at an effective temperature of 5,241 K.[9] It has been examined for the presence of an infrared excess, but none was detected.[8]
There is a common proper motion companion at an angular separation of 16.2″,[4] corresponding to a projected separation of 162.5 astronomical unit|AU.[13] This is a white dwarf star with a classification of DC8.[4] The orbital period of the pair is estimated as 1,110 years.[13]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode: 1986EgUBV........0M.
- ↑ 3.0 3.1 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. doi:10.1086/504637. Bibcode: 2006AJ....132..161G.
- ↑ 4.0 4.1 4.2 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. doi:10.1093/mnras/stt1433. Bibcode: 2013MNRAS.435.2077H.
- ↑ 5.0 5.1 Nidever, David L. et al. (August 2002). "Radial Velocities for 889 Late-Type Stars". The Astrophysical Journal Supplement Series 141 (2): 503–522. doi:10.1086/340570. Bibcode: 2002ApJS..141..503N.
- ↑ Holmberg, J. et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics 501 (3): 941–947, doi:10.1051/0004-6361/200811191, Bibcode: 2009A&A...501..941H.
- ↑ 7.0 7.1 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. doi:10.1086/190905. Bibcode: 1983ApJS...53..643J.
- ↑ 8.0 8.1 8.2 Eiroa, C. et al. (July 2013). "DUst around NEarby Stars. The survey observational results". Astronomy & Astrophysics 555: A11. doi:10.1051/0004-6361/201321050. Bibcode: 2013A&A...555A..11E.
- ↑ 9.0 9.1 9.2 9.3 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. doi:10.1088/0004-637X/756/1/46. Bibcode: 2012ApJ...756...46R.
- ↑ 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. doi:10.1051/0004-6361/200913725. Bibcode: 2010A&A...520A..79M. http://eprints.ucm.es/37826/1/davidmontes17libre.pdf. Retrieved 2018-11-04.
- ↑ 11.0 11.1 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. doi:10.1086/591785. Bibcode: 2008ApJ...687.1264M.
- ↑ "HD 100623". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+100623.
- ↑ 13.0 13.1 Rodriguez, David R. et al. (2015). "Stellar multiplicity and debris discs: An unbiased sample". Monthly Notices of the Royal Astronomical Society 449 (3): 3160. doi:10.1093/mnras/stv483. Bibcode: 2015MNRAS.449.3160R.
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