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HR 4458

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HR 4458
Location of 20 Crateris (circled in red)
Observation data
Epoch J2000      Equinox J2000
Constellation Hydra[1]
A
Right ascension 11h 34m 29.48644s[2]
Declination −32° 49′ 52.8228″[2]
Apparent magnitude (V) 5.97[3]
B
Right ascension 11h 34m 30.47776s[4]
Declination −32° 50′ 02.4048″[4]
Apparent magnitude (V) 15[5]
Characteristics
A
Evolutionary stage main sequence[2]
Spectral type K0 V[6]
U−B color index +0.325[3]
B−V color index +0.80[3]
B
Evolutionary stage white dwarf[5]
Spectral type DC8[7]
Astrometry
A
Radial velocity (Rv)−22.09±0.12[2] km/s
Proper motion (μ) RA: –670.230 mas/yr[2]
Dec.: +822.399 mas/yr[2]
Parallax (π)104.6133±0.0277 mas[2]
Distance31.177 ± 0.008 ly
(9.559 ± 0.003 pc)
Absolute magnitude (MV)6.05[8]
B
Proper motion (μ) RA: –701.802 mas/yr[4]
Dec.: +828.928 mas/yr[4]
Parallax (π)104.6570±0.0267 mas[4]
Distance31.164 ± 0.008 ly
(9.555 ± 0.002 pc)
Absolute magnitude (MV)15[9]
Details
HR 4458 A
Mass0.87[2] M☉
Radius0.84[10] R☉
Luminosity (bolometric)0.368[11] L☉
Surface gravity (log g)4.59[12] cgs
Temperature5,241[12] K
Metallicity [Fe/H]−0.37[12] dex
Rotational velocity (v sin i)6.79[13] km/s
Age4.6–5.8[14] Gyr
HR 4458 B
Mass0.58[15] M☉
Luminosity (bolometric)0.000088[16] L☉
Surface gravity (log g)8.12[17] cgs
Temperature5,000[15] K
Age5.69[15][a] Gyr
Other designations
20 Crt, 289 G. Hya, CD−32°8179, GJ 432, HD 100623, HIP 56452, HR 4458, SAO 202583, LHS 308, LTT 4280, PLX 2678.00[18]
B: VB 4, WD 1132−325
Database references
SIMBADA
B
ARICNSdata

HR 4458 (HD 100623) is a binary star system 31.18 light-years away in the equatorial constellation of Hydra. It has the Flamsteed designation 20 Crateris[19] and the Gould designation 289 G. Hydrae;[20] the former refers to the constellation Crater, since Flamsteed numbered the stars of Crater and the central portion of Hydra as a separate constellation from the other parts of Hydra.[19] This object is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.97.[3] It is moving closer to the Earth with a heliocentric radial velocity of −22 km/s.[21]

The primary component is a K-type main-sequence star with a stellar classification of K0 V.[6] It is around five billion years old[14] with 84% of the Sun's radius.[10] The star is radiating 37% of the Sun's luminosity[11] from its photosphere at an effective temperature of 5,241 K.[12] It has been examined for the presence of an infrared excess, but none was detected.[11]

There is a 15th-magnitude common proper motion companion called VB4 at an angular separation of 16.2″,[7] corresponding to a projected separation of 162.5 AU.[22] This is a white dwarf star with a classification of DC8.[7] The orbital period of the pair is estimated as 1,110 years.[22]

Notes

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  1. ^ Cooling age

References

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  1. ^ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
  2. ^ a b c d e f g 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.
  3. ^ a b c d Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
  4. ^ a b c d 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.
  5. ^ a b Holberg, J. B.; Oswalt, Terry D.; Sion, E. M. (2002). "A Determination of the Local Density of White Dwarf Stars". The Astrophysical Journal. 571 (1): 512–518. arXiv:astro-ph/0102120. Bibcode:2002ApJ...571..512H. doi:10.1086/339842.
  6. ^ a b 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. S2CID 119476992.
  7. ^ a b c 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.
  8. ^ 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. arXiv:0811.3982. Bibcode:2009A&A...501..941H. doi:10.1051/0004-6361/200811191. S2CID 118577511.
  9. ^ Reid, I. Neill; Hawley, Suzanne L.; Gizis, John E. (1995). "The Palomar/MSU Nearby-Star Spectroscopic Survey. I. The Northern M Dwarfs -Bandstrengths and Kinematics". The Astronomical Journal. 110: 1838. Bibcode:1995AJ....110.1838R. doi:10.1086/117655.
  10. ^ a b Johnson, H. M.; Wright, C. D. (1983). "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.
  11. ^ a b c 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. S2CID 377244.
  12. ^ a b c d 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. S2CID 119199829.
  13. ^ 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. S2CID 43455849.
  14. ^ a b 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. S2CID 27151456.
  15. ^ a b c Bagnulo, S.; Landstreet, J. D. (2021). "New insight into the magnetism of degenerate stars from the analysis of a volume-limited sample of white dwarfs". Monthly Notices of the Royal Astronomical Society. 507 (4): 5902. arXiv:2106.11109. Bibcode:2021MNRAS.507.5902B. doi:10.1093/mnras/stab2046.
  16. ^ Holberg, J. B.; Oswalt, T. D.; Sion, E. M.; McCook, G. P. (2016). "The 25 parsec local white dwarf population". Monthly Notices of the Royal Astronomical Society. 462 (3): 2295. arXiv:1606.01236. Bibcode:2016MNRAS.462.2295H. doi:10.1093/mnras/stw1357.
  17. ^ Hollands, M. A.; Tremblay, P. -E.; Gänsicke, B. T.; Gentile-Fusillo, N. P.; Toonen, S. (2018). "The Gaia 20 pc white dwarf sample". Monthly Notices of the Royal Astronomical Society. 480 (3): 3942. arXiv:1805.12590. Bibcode:2018MNRAS.480.3942H. doi:10.1093/mnras/sty2057.
  18. ^ "HD 100623". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved May 6, 2019.
  19. ^ a b Wagman, M. (August 1987). "Flamsteed's Missing Stars". Journal for the History of Astronomy. 18 (3): 215. Bibcode:1987JHA....18..209W. doi:10.1177/002182868701800305. S2CID 118445625.
  20. ^ Gould, Benjamin Apthorp (1879). "Uranometria Argentina catalog of bright southern stars". Resultados del Observatorio Nacional Argentino en Cordoba. 1. Buenos Aires. Bibcode:1879RNAO....1.....G. Retrieved 2012-05-08.
  21. ^ 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. S2CID 51814894.
  22. ^ a b Rodriguez, David R.; et al. (2015). "Stellar multiplicity and debris discs: An unbiased sample". Monthly Notices of the Royal Astronomical Society. 449 (3): 3160. arXiv:1503.01320. Bibcode:2015MNRAS.449.3160R. doi:10.1093/mnras/stv483.
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