HD 133981

HD 133981

Observation data Epoch J2000      Equinox J2000
Constellation	Apus
Right ascension	15^h 12^m 33.97907^s[1]
Declination	−72° 46′ 14.1634″[1]
Apparent magnitude (V)	6.02±0.01[2]
Characteristics
Spectral type	B8 IV[3]
U−B color index	−0.24[4]
B−V color index	0.00[4]
Astrometry
Radial velocity (Rv)	−13.7±1.3[5] km/s
Proper motion (μ)	RA: −14.107 mas/yr[1] Dec.: −16.361 mas/yr[1]
Parallax (π)	3.8088 ± 0.0418 mas[1]
Distance	856 ± 9 ly (263 ± 3 pc)
Absolute magnitude (MV)	−1.34[6]
Details
Mass	3.72^+0.09 −0.05[1] M☉
Radius	6.35[7] R☉
Luminosity	364^+15 −14[1] L☉
Surface gravity (log g)	3.48[8] cgs
Temperature	10,250[9] K
Metallicity [Fe/H]	0.00[10] dex
Age	202^+23 −2[1] Myr
Other designations
25 G. Apodis[11], CD−72°1096, CPD−72°1714, GC 20391, HD 133981, HIP 74421, HR 5628, SAO 257247[12]
Database references
SIMBAD	data

HD 133981, also known as HR 5628, is a solitary, bluish-white hued star located in the southern circumpolar constellation of Apus. It has an apparent magnitude of 6.02,[2] allowing it to be faintly visible to the naked eye in ideal conditions. The object is located relatively far at a distance of 856 light years based on parallax measurements from Gaia DR3[1] but is approaching the Solar System with a heliocentric radial velocity of −13.7 km/s.[5]

HD 133981 has a stellar classification of B8 IV,[3] indicating that it is a B-type star that is evolving towards the red giant branch. Houk and Cowley (1975) gave a slightly more evolved class of B8/9 III,[13] instead indicating that it is a giant star. Some evolutionary models show that it is a star just reaching the end of the main sequence.[1] Nevertheless, it has 3.72 times the mass of the Sun[1] and 6.35 times its girth.[7] It radiates 364 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 10,250 K.[9] HD 133981 is said to be 202 million years old.[1]

HD 133981 lies in front of the distant faint galaxy LEDA 54288.[14] A debris disk has been detected around the star. It has 22.5 times the mass of the Earth and an equilibrium temperature of 27 K.[9]

The HD 133981 planetary system

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
circumstellar disc	1,851 AU				—	—

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. 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.
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. 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. 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.
9. Liu, Qiong; Wang, Tinggui; Jiang, Peng (23 May 2014). "Bright Debris Disk Candidates Detected with the AKARI/Far-infrared Surveyor". The Astronomical Journal. 148 (1): 3. arXiv:1308.5593. Bibcode:2014AJ....148....3L. doi:10.1088/0004-6256/148/1/3. eISSN 1538-3881. ISSN 0004-6256.
10. 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.
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 133981". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 9, 2022.
13. 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.
14. "LEDA 54288". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2022-09-01.