HD 4222

HD 4222

Location of HD 4222 on the map (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Cassiopeia
A
Right ascension	00^h 45^m 17.17365^s[1]
Declination	+55° 13′ 17.0310″[1]
Apparent magnitude (V)	5.41±0.01[2]
B
Right ascension	00^h 45^m 17.14092^s[3]
Declination	+55° 13′ 15.4000″[3]
Apparent magnitude (V)	11.5[4]
Characteristics
A
Evolutionary stage	main sequence star[5]
Spectral type	A2 Vs[6] or A1 V[7]
U−B color index	+0.05[8]
B−V color index	+0.04[8]
B
Spectral type	M2-5V[9]
Astrometry
Radial velocity (Rv)	−8.5±2[10] km/s
Proper motion (μ)	RA: −29.935 mas/yr[1] Dec.: −5.616 mas/yr[1]
Parallax (π)	9.2342 ± 0.0586 mas[1]
Distance	353 ± 2 ly (108.3 ± 0.7 pc)
Absolute magnitude (MV)	+0.44[11]
Details
A
Mass	2.59±0.04[5] M☉
Radius	3.47±0.18[12] R☉
Luminosity	69.1^+5.6 −5.2[5] L☉
Surface gravity (log g)	3.72^+0.08 −0.06[13] cgs
Temperature	9,886[14] K
Metallicity [Fe/H]	−0.26[15] dex
Rotational velocity (v sin i)	25±8[7] km/s
Age	407^+51 −52[1] Myr
Other designations
AG+54°69, BD+54°143, GC 894, HD 4222, HIP 3544, HR 196, SAO 21677, ADS 625 A, CCDM J00453+5514A, WDS J00453+5513A, TIC 445136120[16]
Database references
SIMBAD	data

HD 4222, also known as HR 196, is the primary of a binary star[17] located in the northern constellation Cassiopeia. It is faintly visible to the naked eye as a white-hued point of light with an apparent magnitude of 5.41.[2] Gaia DR3 parallax measurements imply a distance of 353 light-years and it is drifting closer with a heliocentric radial velocity of −8.5 km/s.[10] At its current distance, HD 4222's brightness is diminished by an interstellar extinction of 0.13 magnitudes and it has an absolute magnitude of +0.44.[11]

HD 4222 has a stellar classification of A2 Vs or A1 V,[6][7] both classes indicating that it is an A-type main-sequence star that is generating energy via hydrogen fusion at its core. The former class includes the presence of 'sharp' or narrow absorption lines due to slow rotation. Consistent with the class, HD 4222 spins modestly with a projected rotational velocity of approximately 25 km/s.[7] It has 2.59 times the mass of the Sun[5] and 3.47 times the radius of the Sun.[12] It radiates 69.1 times the luminosity of the Sun[5] from its photosphere with an effective temperature of 9,886 K.[14] HD 4222 is metal deficient with an iron abundance of [Fe/H] = −0.26 or 55% of the Sun's.[15] At the age of 407 million years,[1] HD 4222 has completed 81.5% of its main sequence lifetime.[5]

HD 4222 and BU 492B make up the binary system BU 492. The companion is a red dwarf with a stellar classification of M2-5V; it is located 1.5" away from the primary along a position angle of 173°. BU 492B was first noticed by astronomer S. W. Burnham in 1878. HD 4222 also has one optical companion; an 11th magnitude star located 88.6" away, which itself is also a double star.[4] A X-ray emission with a luminosity of 3.031×10^20 W was detected around the star.[9] A-type stars are not expected to emit X-rays, so it might be coming from the companion. HD 4222 is considered to be a probable member of the Sirius supercluster, a group of stars moving with the bright star Sirius and share a common origin with the system.[18]

References

1. 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.
2. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27 – L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361. S2CID 17128864.
3. 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.
4. Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (December 2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. ISSN 0004-6256. S2CID 119533755.
5. Zorec, J.; Royer, F. (January 2012). "Rotational velocities of A-type stars IV: Evolution of rotational velocities". Astronomy & Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691. eISSN 1432-0746. ISSN 0004-6361. S2CID 55586789.
6. Cowley, A.; Cowley, C.; Jaschek, M.; Jaschek, C. (April 1969). "A study of the bright stars. I. A catalogue of spectral classifications". The Astronomical Journal. 74: 375. Bibcode:1969AJ.....74..375C. doi:10.1086/110819. ISSN 0004-6256. S2CID 121555804.
7. Abt, Helmut A.; Morrell, Nidia I. (July 1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". The Astrophysical Journal Supplement Series. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182. ISSN 0067-0049. S2CID 120495962.
8. Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode:1986EgUBV........0M
9. Schröder, C.; Schmitt, J. H. M. M. (24 September 2007). "X-ray emission from A-type stars". Astronomy & Astrophysics. 475 (2): 677–684. Bibcode:2007A&A...475..677S. doi:10.1051/0004-6361:20077429. eISSN 1432-0746. ISSN 0004-6361.
10. Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication: 0. Bibcode:1953GCRV..C......0W. S2CID 120000732.
11. Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. eISSN 1562-6873. ISSN 1063-7737. S2CID 119257644.
12. Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (April 8, 2004). "The angular sizes of dwarf stars and subgiants: Surface brightness relations calibrated by interferometry". Astronomy & Astrophysics. 426 (1): 297–307. arXiv:astro-ph/0404180. Bibcode:2004A&A...426..297K. doi:10.1051/0004-6361:20035930. eISSN 1432-0746. ISSN 0004-6361. S2CID 6077801.
13. Stassun, Keivan G.; et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. eISSN 1538-3881. hdl:1721.1/124721. S2CID 166227927.
14. Fracassini, M.; Manzolini, F.; Pasinetti, L. E.; Ruggenini, M. (May 1980). "Apparent radii and other parameters for 416 B5 V-F5 V stars of the catalogue of the Geneva observatory". Astrophysics and Space Science. 69 (2). Springer Science and Business Media LLC: 401–423. Bibcode:1980Ap&SS..69..401F. doi:10.1007/bf00661927. ISSN 0004-640X. S2CID 189849072.
15. Anders, F.; et al. (August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy & Astrophysics. 628: A94. arXiv:1904.11302. Bibcode:2019A&A...628A..94A. doi:10.1051/0004-6361/201935765. eISSN 1432-0746. ISSN 0004-6361. S2CID 131780028.
16. "HD 4222". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved November 8, 2023.
17. Eggleton, P. P.; Tokovinin, A. A. (11 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. eISSN 1365-2966. ISSN 0035-8711. S2CID 14878976.
18. Eggen, O. J. (June 1, 1960). "Stellar Groups, VIII. The Structure of the Sirius Group". Monthly Notices of the Royal Astronomical Society. 120 (6). Oxford University Press (OUP): 563–580. Bibcode:1960MNRAS.120..563E. doi:10.1093/mnras/120.6.563. ISSN 0035-8711. S2CID 119805328.