HD 76270

HD 76270, also known as HR 3544, is a solitary, white hued star located in the southern circumpolar constellation Volans. It has an apparent magnitude of 6.10,[2] making it faintly visible to the naked eye if viewed under ideal conditions. The object is relatively far with a distance of 2,360 light years,[1] but is slowly approaching the Solar System with a heliocentric radial velocity of −2.6 km/s.[5]

HD 76270
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Volans
Right ascension 08h 49m 50.12604s[1]
Declination −72° 33′ 04.4601″[1]
Apparent magnitude (V) 6.10±0.01[2]
Characteristics
Spectral type A5 III/IV[3]
U−B color index +0.17[4]
B−V color index +0.20[4]
Astrometry
Radial velocity (Rv)−2.6±1.1[5] km/s
Proper motion (μ) RA: −6.191 mas/yr[1]
Dec.: +8.368 mas/yr[1]
Parallax (π)1.3842 ± 0.0201 mas[1]
Distance2,360 ± 30 ly
(720 ± 10 pc)
Details
Mass5.3[6] M☉
Radius22.9[7] R☉
Luminosity1,464±55[8] L☉
Surface gravity (log g)2.27[9] cgs
Temperature8,121±123[7] K
Metallicity [Fe/H]−0.44[10] dex
Other designations
44 G. Volantis[11], CD−72°488, CPD−72°747, GC 12252, HD 76720, HIP 35541, HR 3544, SAO 256556[12]
Database references
SIMBADdata

HD 76270 was considered as a chemically peculiar Am star, and as a result, was given a spectral classification of A3mA6-7[3] by Nancy Houk and A.P Cowley. This means it is an A3 star with the metallic lines of a star with a class of A6-7. However, this peculiarity is now considered doubtful.[13] An alternate class of A5 III/IV[3] was given, instead making it an evolved A-type star with a blended luminosity class of a subgiant and a giant star.

At present it has 5.3 times the mass of the Sun[6] but has expanded to 22.9 times its girth.[7] It shines with a high luminosity of 1,464 L☉[8] from its enlarged photosphere at an effective temperature of 8,121 K.[7] HR 3544 is metal deficient, having an iron abundance 64% below solar levels.[10] A 1984 study used HD 76270 as a comparison star and suspected it of being slightly variable,[14] but this has not been confirmed and it is not even listed as a suspected variable in the General Catalogue of Variable Stars.[15]

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.
  3. Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Volume I. Declinations −90° to −53°. Bibcode:1975mcts.book.....H.
  4. Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99–110. Bibcode:1966CoLPL...4...99J.
  5. Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. eISSN 1562-6873. ISSN 1063-7737. S2CID 119231169.
  6. Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics. 657: A7. arXiv:2109.10912. Bibcode:2022A&A...657A...7K. doi:10.1051/0004-6361/202142146. eISSN 1432-0746. ISSN 0004-6361.
  7. 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.
  8. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  9. Anders, F.; et al. (February 2022). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G = 18.5". Astronomy & Astrophysics. 658: A91. arXiv:2111.01860. Bibcode:2022A&A...658A..91A. doi:10.1051/0004-6361/202142369. eISSN 1432-0746. ISSN 0004-6361.
  10. Hauck, B.; Curchod, A. (December 1980). "Properties of AM stars in the Geneva photometric system". Astronomy and Astrophysics. 92: 289–295. Bibcode:1980A&A....92..289H. ISSN 0004-6361.
  11. Gould, Benjamin Apthorp (1878). "Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas". Resultados del Observatorio Nacional Argentino. 1. Bibcode:1879RNAO....1.....G.
  12. "HR 3544". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 6, 2022.
  13. Renson, P.; Manfroid, J. (19 March 2009). "Catalogue of Ap, HgMn and Am stars". Astronomy & Astrophysics. 498 (3): 961–966. Bibcode:2009A&A...498..961R. doi:10.1051/0004-6361/200810788. eISSN 1432-0746. ISSN 0004-6361.
  14. Hensberge, H.; Manfroid, J.; Schneider, H.; Maitzen, H. M.; Catalano, F. A.; Renson, P.; Weiss, W. W.; Floquet, M. (1984). "The frequency of Ap-stars with long rotation periods". Astronomy and Astrophysics. 132: 291. Bibcode:1984A&A...132..291H.
  15. Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
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