HD 142990

A light curve for V913 Scorpii, plotted from Kepler K2 data.[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Scorpius
Right ascension 15h 58m 34.86657s[2]
Declination −24° 49′ 53.3617″[2]
Apparent magnitude (V) 5.40 - 5.47[3]
Characteristics
Spectral type B5 V[4]
U−B color index -0.65[5]
B−V color index -0.09[5]
Variable type SXARI[3]
Astrometry
Proper motion (μ) RA: −12.451±0.100[2] mas/yr
Dec.: −24.582±0.061[2] mas/yr
Parallax (π)7.0050 ± 0.0908 mas[2]
Distance466 ± 6 ly
(143 ± 2 pc)
Details
Mass5.7±0.1[6] M☉
Radius2.80±0.04[6] R☉
Luminosity794[6] L☉
Surface gravity (log g)4.15±0.11[6] cgs
Temperature18000±500[6] K
Rotation0.978832±0.000002 d[7]
Rotational velocity (v sin i)122±2[8] km/s
Age5.0+1.3
−1.0[9] Myr
Other designations
V913 Sco, HR 5942, HIP 78246, SAO 183982[10]
Database references
SIMBADdata

HD 142990, also known as HR 5942 and V913 Scorpii, is a star about 470 light years from the Earth, in the constellation Scorpius.[2] It is a 5th magnitude star, so it will be faintly visible to the naked eye of an observer far from city lights.[2] It is a variable star, whose brightness varies slightly from 5.40 to 5.47 during its 23.5 hour rotation period.[11][3] It is a member of the Upper Scorpius Region of the Scorpius–Centaurus association.[12]

HD 142990 is a helium-weak star.[13] In 1983, Ermanno Borra et al. detected the star's strong (~kilogauss) magnetic field from the Zeeman splitting of the Hβ spectral line.[13] Later estimates put the field strength as several kilogauss.[9]

The variability of HD 142990 was discovered in 1977 by Holger Pedersen and Bjarne Thomsen, during a spectroscopic and photometric study of helium weak and helium strong stars.[14] In 1978 the star was given the variable star designation V913 Scorpii.[15] Far more extensive photometric data were provided by the Kepler K2 program, which sampled the light curve well, and allowed Dominic Bowman et al. to measure the star's 0.978832±0.000002 day rotation period.[7]

The rotation period of HD 142990 appears to be decreasing at a rate of about 0.6 seconds per year. This might mean the star is still contracting towards the zero-age main sequence, though other explanations involving magnetohydrodynamics have been proposed.[16]

In 1989, Jeffrey Linsky et al. reported the detection of 6 cm radio emission from HD 142990, which appeared to be variable on a time scale of 5 minutes.[17] In 2018, Emil Lenc et al. found that the radio emission from the star is circularly polarized.[18] In 2019, Barnali Das et al. reported that HD 142990 exhibits coherent electron cyclotron maser emission at 200 MHz, making it, at that time, only the fourth hot magnetic star known to emit by this mechanism .[6]

References

  1. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 23 February 2023.
  2. 1 2 3 4 5 6 7 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.
  3. 1 2 3 N. N. Samus; O. V. Durlevich; et al. "V913 Sco database entry". Combined General Catalog of Variable Stars (2017 ed.). CDS. Retrieved 2023-02-24.
  4. ↑ Houk, N.; Smith-Moore, M. (1988). Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume 4, Declinations -26°.0 to -12°. Department of Astronomy, University of Michigan.
  5. 1 2 Garrison, R. F. (March 1967). "Some Characteristics of the B and A Stars in the Upper Scorpius Complex". Astrophysical Journal. 147: 1003–1016. Bibcode:1967ApJ...147.1003G. doi:10.1086/149090. S2CID 121615150. Retrieved 25 February 2023.
  6. 1 2 3 4 5 6 Das, Barnali; Chandra, Poonam; Shultz, Matt E.; Wade, Gregg A. (June 2019). "Detection of Coherent Emission from the Bp Star HD 142990 at uGMRT Frequencies". The Astrophysical Journal. 877 (2): 123. arXiv:1904.08359. Bibcode:2019ApJ...877..123D. doi:10.3847/1538-4357/ab1b12. S2CID 119116341.
  7. 1 2 Bowman, D. M.; Buysschaert, B.; Neiner, C.; Pápics, P. I.; Oksala, M. E.; Aerts, C. (August 2018). "K2 space photometry reveals rotational modulation and stellar pulsations in chemically peculiar A and B stars". Astronomy and Astrophysics. 616: A77. arXiv:1805.01799. Bibcode:2018A&A...616A..77B. doi:10.1051/0004-6361/201833037. S2CID 53955873. Retrieved 25 February 2023.
  8. ↑ Shultz, M. E.; Wade, G. A.; Rivinius, Th.; Neiner, C.; Alecian, E.; Bohlender, D.; Monin, D.; Sikora, J.; MiMeS Collaboration; BinaMIcS Collaboration (January 2018). "The magnetic early B-type stars I: magnetometry and rotation". Monthly Notices of the Royal Astronomical Society. 475 (4): 5144–5178. arXiv:1801.02924. Bibcode:2018MNRAS.475.5144S. doi:10.1093/mnras/sty103. Retrieved 25 February 2023.
  9. 1 2 Shultz, Matthew (August 2016). The Rotational Evolution and Magnetospheric Emission of the Magnetic Early B-type Stars (PhD Thesis). Queen's University. Retrieved 25 February 2023.
  10. ↑ "V913 Sco -- Rotating Variable". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2023-02-18.
  11. ↑ "V0913 Sco". The International Variable Star Index. AAVSO. Retrieved 24 February 2023.
  12. ↑ Bertiau, F. C. (November 1958). "Absolute Magnitudes of Stars in the Scorpio-Centaurus Association". Astrophysical Journal. 128: 533–561. Bibcode:1958ApJ...128..533B. doi:10.1086/146569. Retrieved 24 February 2023.
  13. 1 2 Borra, E. F.; Landstreet, J. D.; Thompson, I. (September 1983). "The magnetic fields of the helium-weak B stars". Astrophysical Journal Supplement Series. 53: 151–167. Bibcode:1983ApJS...53..151B. doi:10.1086/190889. Retrieved 25 February 2023.
  14. ↑ Pedersen, H.; Thomsen, B. (October 1977). "Spectrum and photometric variability of He-weak and He-strong stars". Astronomy and Astrophysics Suppl. Ser. 30: 11–25. Bibcode:1977A&AS...30...11P. Retrieved 25 February 2023.
  15. ↑ Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (April 1979). "64th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 1581: 1. Bibcode:1979IBVS.1581....1K. Retrieved 25 February 2023.
  16. ↑ Shultz, M.; Rivinius, Th.; Das, B.; Wade, G. A.; Chandra, P. (July 2019). "The accelerating rotation of the magnetic He-weak star HD 142990". Monthly Notices of the Royal Astronomical Society. 486 (4): 5558–5566. arXiv:1904.08887. Bibcode:2019MNRAS.486.5558S. doi:10.1093/mnras/stz1129. Retrieved 25 February 2023.
  17. ↑ Linsky, J. L.; Drake, S. A.; Bastian, T. S. (March 1989). "Extension of the Class of Magnetic B Star Nonthermal Radio Sources". Bulletin of the American Astronomical Society. 21: 742. Bibcode:1989BAAS...21Q.742L. Retrieved 25 February 2023.
  18. ↑ Lenc, Emil; Murphy, Tara; Lynch, C. R.; Kaplan, D. L.; Zhang, S. N. (August 2018). "An all-sky survey of circular polarization at 200 MHz". Monthly Notices of the Royal Astronomical Society. 478 (2): 2835–2849. arXiv:1805.05482. Bibcode:2018MNRAS.478.2835L. doi:10.1093/mnras/sty1304. Retrieved 25 February 2023.
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