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HR 3831

Coordinates: Sky map 09h 36m 25.4069s, −48° 45′ 04.2549″
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HR 3831

A light curve for IM Velorum (HR 3831), plotted from TESS data.[1] The 2.852 day period[2] is shown in red.
Observation data
Epoch J2000      Equinox J2000
Constellation Vela
HD 83368A
Right ascension 09h 36m 25.4255s[3]
Declination −48° 45′ 04.240″[3]
Apparent magnitude (V) 6.23[4]
HD 83368B
Right ascension 09h 36m 25.3660s[5]
Declination −48° 45′ 07.505″[5]
Apparent magnitude (V) 10.31[4]
Characteristics
HD 83368A
Spectral type A8V[6]
Variable type Rapidly oscillating Ap
HD 83368B
Spectral type F9V[7]
Astrometry
HD 83368A
Proper motion (μ) RA: -8.16±0.03 mas/yr[3]
Dec.: -18.85±0.03 mas/yr[3]
Parallax (π)14.01±0.03 mas[3]
Distance232.8 ± 0.5 ly
(71.4 ± 0.2 pc)
HD 83368B
Radial velocity (Rv)-4.0±0.3[5] km/s
Proper motion (μ) RA: -9.41±0.19 mas/yr[5]
Dec.: -14.00±0.17 mas/yr[5]
Parallax (π)14.31 ± 0.15 mas[5]
Distance228 ± 2 ly
(69.9 ± 0.7 pc)
Details
Aa
Mass1.78+0.12
−0.17[8] M☉
Radius2.003[9] R☉
Luminosity (bolometric)12.33[9] L☉
Surface gravity (log g)4.2[9] cgs
Temperature7650[9] K
Rotation2.851976±0.00003 d[9]
Rotational velocity (v sin i)33.8±1.0[8] km/s
Age0.93+0.42
−0.34[8] Gyr
Ab
Mass0.64[10] M☉
Radius0.60[10] R☉
Temperature4,175[10] K
B
Mass1[10] M☉
Other designations
CD−48 4831, HD 83368, HIP 47145, HR 3831, SAO 221339, GSC 08176-00283, IM Vel[6]
HD 83368A: 2MASS J09362541-4845042, TYC 8176-283-1
HD 83368B: 2MASS J09362537-4845072, Gaia DR2 5410092611662456704, TYC 8176-2818-1
Database references
SIMBADdata

HR 3831, also known as HD 83368, is a triple star system in the southern constellation of Vela at a distance of 233 light years. This object is barely visible to the naked eye as a dim, blue star with an apparent visual magnitude of 6.232. It is approaching the Earth with a heliocentric radial velocity of 4.0±0.3 km/s.[5]

The star system is a hierarchical binary, made up of an inner and an outer pair. The inner pair has an orbital separation of 13 astronomical units, and contain the primary star, HR 3831 Aa, and the secondary HR 3831 Ab. The outer component have a 214 AU projected separation from the inner pair.[10] The primary star, HR 3831 Aa, is a pulsating variable of a rapidly oscillating Ap type. It has a single yet strongly distorted dipole pulsation mode with a frequency of 1427 μHz.[11] The primary star is chemically peculiar, exhibiting spots of enhanced concentrations of lithium, europium and oxygen.[9]

The star's variability was discovered by Pierre Renson, and announced in 1977.[12] It was given its variable star designation, IM Velorum, in 1981.[13]

See also

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References

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  1. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 27 September 2024.
  2. ^ Kurtz, D. W.; van Wyk, F; Roberts, G.; Marang, F.; Handler, G.; Medupe, R.; Kilkenny, D. (May 1997). "Frequency variability in the rapidly oscillating AP star HR 3831: three more years of monitoring". Monthly Notices of the Royal Astronomical Society. 287 (1): 69–78. Bibcode:1997MNRAS.287...69K. doi:10.1093/mnras/287.1.69.
  3. ^ 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.
  4. ^ a b Fabricius, C.; Høg, E.; Makarov, V. V.; Mason, B. D.; Wycoff, G. L.; Urban, S. E. (2002). "The Tycho double star catalogue". Astronomy and Astrophysics. 384: 180. Bibcode:2002A&A...384..180F. doi:10.1051/0004-6361:20011822.
  5. ^ a b c d e f 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.
  6. ^ a b "HD 83368". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved June 30, 2021.
  7. ^ "HD 83368B". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved June 30, 2021.
  8. ^ a b c Sikora, J.; Wade, G. A.; Power, J.; Neiner, C. (2019), "A volume-limited survey of MCP stars within 100 pc – I. Fundamental parameters and chemical abundances", Monthly Notices of the Royal Astronomical Society, 483 (2): 2300–2324, arXiv:1811.05633, Bibcode:2019MNRAS.483.2300S, doi:10.1093/mnras/sty3105
  9. ^ a b c d e f Kochukhov, O. (2005), "Pulsational line profile variation of the roAp star HR 3831", Astronomy & Astrophysics, 446 (3): 1051–1070, arXiv:astro-ph/0509446, doi:10.1051/0004-6361:20053345, S2CID 13102520
  10. ^ a b c d e Waisberg, Idel; Klein, Ygal; Katz, Boaz (April 2023). "Discovery of a 0.64 M☉, 13.4 au Companion to the roAp Star HIP 47145 = HR 3831 = IM Vel*". Research Notes of the AAS. 7 (4): 66. doi:10.3847/2515-5172/accb5d. ISSN 2515-5172.
  11. ^ Bigot, L.; Kurtz, D. W. (2011), "Theoretical light curves of dipole oscillations in roAp stars", Astronomy & Astrophysics, 536: A73, arXiv:1110.0988, Bibcode:2011A&A...536A..73B, doi:10.1051/0004-6361/201116981, S2CID 54532822
  12. ^ Renson, P. (20 May 1977). "Periodicite d'Etoiles Ap Australes" (PDF). Invormal Bulletin on Variable Stars. 1280: 1. Bibcode:1977IBVS.1280....1R. Retrieved 20 October 2024.
  13. ^ Kholopov, P. N.; Samus, N. N.; Kukarkina, N. P.; Medvedeva, G. I.; Perova, N. B. (February 1981). "65th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 1921: 1. Bibcode:1981IBVS.1921....1K. Retrieved 20 October 2024.
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