HD 138867

HD 138867

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Apus
Right ascension	15^h 41^m 54.68806^s[1]
Declination	−76° 04′ 55.0718″[1]
Apparent magnitude (V)	5.94±0.01[2]
Characteristics
Evolutionary stage	main sequence[3]
Spectral type	B9.5 V[4]
Astrometry
Radial velocity (Rv)	1.1±1.7[5] km/s
Proper motion (μ)	RA: −12.407 mas/yr[1] Dec.: −41.541 mas/yr[1]
Parallax (π)	7.8146 ± 0.0916 mas[1]
Distance	417 ± 5 ly (128 ± 1 pc)
Absolute magnitude (MV)	+0.4[6]
Details
Mass	2.81[3] M☉
Radius	2.59±0.09[7] R☉
Luminosity	54.9[8] L☉
Surface gravity (log g)	4.04±0.07[7] cgs
Temperature	10,375±48[3] K
Metallicity [Fe/H]	0.00[9] dex
Rotational velocity (v sin i)	178[10] km/s
Age	272[9] Myr
Other designations
34 G. Apodis[11], CPD−75°1222, FK5 3235, GC 21025, HD 138867, HIP 76877, HR 5786, SAO 257310[12]
Database references
SIMBAD	data

HD 138867, also known as HR 5786, is a bluish-white hued star located in the southern circumpolar constellation Apus. It has an apparent magnitude of 5.94,[2] making it faintly visible to the naked eye if viewed under ideal conditions. Based on parallax measurements from the Gaia spacecraft, it is estimated to be 417 light years away from Earth.[1] However, it is receding with a heliocentric radial velocity of 1.1 km/s.[5]

HD 138867 has a stellar classification of B9.5 V,[4] indicating that it is a B-type main-sequence star just shy of being an A-type star. It has 2.81 times the mass of the Sun[3] and is estimated to be 272 million years,[9] having completed 67.4% of its main sequence lifetime.[3] HD 138867 has an effective temperature of 10,375 K,[3] which combined with a radius of 2.59 R_☉,[7] yields a luminosity over 50 times that of Sun.[8] A solar metallicity has been calculated for HD 138867.[9] It is currently spinning rapidly with a projected rotational velocity of 178 km/s.[10]

There has been disagreement in regards to HD 138867's muplicity. Chini et al. (2012) list it as a solitary star[13] while Eggleton and Tokovinn (2008) found it to be an astrometric binary.[14] The first one is more likely as the object has a constant radial velocity.

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. Zorec, J.; Royer, F. (January 2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691. ISSN 0004-6361. S2CID 55586789.
4. 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.
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. 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.
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. McDonald, I.; Zijlstra, A. A.; Watson, R. A. (15 June 2017). "Fundamental parameters and infrared excesses of Tycho–Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770–791. arXiv:1706.02208. Bibcode:2017MNRAS.471..770M. doi:10.1093/mnras/stx1433. eISSN 1365-2966. ISSN 0035-8711.
9. Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters. 38 (12): 771–782. arXiv:1606.08814. Bibcode:2012AstL...38..771G. doi:10.1134/S1063773712120031. ISSN 0320-0108. S2CID 118345778.
10. Levato, H.; Grosso, M. (June 2004). "New Projected Rotational Velocities of All Southern B-type Stars of the Bright Star Catalogue". Astronomical Society of the Pacific. 215: 51. Bibcode:2004IAUS..215...51L.
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. "HD 138867". SIMBAD. Centre de données astronomiques de Strasbourg.
13. Chini, R.; Hoffmeister, V. H.; Nasseri, A.; Stahl, O.; Zinnecker, H. (10 July 2012). "A spectroscopic survey on the multiplicity of high-mass stars". Monthly Notices of the Royal Astronomical Society. 424 (3): 1925–1929. arXiv:1205.5238. Bibcode:2012MNRAS.424.1925C. doi:10.1111/j.1365-2966.2012.21317.x. ISSN 0035-8711.
14. 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.