V1005 Orionis

Ultraviolet (U band) light curves for two flares on V1005 Orionis, adapted from Byrne et al. (1984)[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Orion
Right ascension 04h 59m 34.834s[2]
Declination +01° 47′ 00.67″[2]
Apparent magnitude (V) 10.107±0.053[3] (9.96 to 10.17)[4]
Evolutionary stage Main sequence
Spectral type M0Ve[5]
B−V color index 1.394±0.020[6]
Variable type BY Dra, UV Cet[4]
Radial velocity (Rv)19.16±0.0058[7] km/s
Proper motion (μ) RA: 39.130 mas/yr[2]
Dec.: −94.900 mas/yr[2]
Parallax (π)40.9899 ± 0.0128 mas[2]
Distance79.57 ± 0.02 ly
(24.396 ± 0.008 pc)
Absolute magnitude (MV)7.96[8]
Mass0.75±0.01[9] M
Radius0.74±0.02[9] R
Luminosity0.12[6] L
Luminosity (bolometric)0.14±0.01[9] L
Surface gravity (log g)4.5[10] cgs
Temperature3,843±60[11] K
Metallicity [Fe/H]0.14±0.11[11] dex
Rotation4.4236±0.001 d[12]
Rotational velocity (v sin i)8.7±1.6[7] km/s
Age25[7] Myr
Other designations
V1005 Ori, GJ 182, HIP 23200[13]
Database references

V1005 Orionis is a young flare star in the equatorial constellation of Orion. It has the identifier GJ 182 in the Gliese–Jahreiß catalogue; V1005 Ori is its variable star designation. This star is too faint to be visible to the naked eye, having a mean apparent visual magnitude of 10.1.[3] It is located at a distance of 79.6[2] light years from the Sun and is drifting further away with a radial velocity of 19.2 km/s.[7] The star is a possible member of the IC 2391 supercluster.[14][15]

Flare activity was first reported for this star by N. I. Shakhovskaya in 1974.[16] B. W. Bopp found anomalously strong lithium lines in the spectrum of GJ 182, a rarity for stars of this class and a possible indicator of a very young star.[17] Together with F. Espenak, in 1977 Bopp demonstrated the star showed periodic variations similar to BY Draconis.[18] In 1984, Byrne and associates found a preliminary rotation period of 4.55 days and showed the star had a normal flare rate.[1]

The stellar classification of V1005 Ori is M0Ve,[5] indicating this is an M-type main-sequence star (a "red dwarf") with emission lines (e) in its spectrum. It is classified as a BY Draconis and UV Ceti variable,[4] which means it is a magnetically active star that exhibits rotational modulation of star spots and undergoes sudden increases in brightness from flares.[12] Because of this activity, the star displays a low level of X-ray emission.[19][9] The surface magnetic field strength is 2.6±0.6 kG and the magnetic field has multiple poles.[20] It shows a possible activity cycle with a period of 38 years and an amplitude of 0.13 in magnitude.[21]

This star is an estimated 25 million years old and is currently about a half magnitude above the main sequence. However, the high lithium content suggests it may be as young as 10–15 million years, as this element is typically expected to be depleted after 20 million years. It is spinning with a projected rotational velocity of ~9 km/s, and a rotation period of 4.4 days suggests it is being viewed from close to the equatorial plane.[7] The star has less mass, a smaller radius, and a lower luminosity compared to the Sun.[9]

V1005 Ori is surrounded by a circumstellar disk of dust that indicates planetary formation is under way.[15] This disk has a radius of 60 AU, a mean temperature of 27 K, and a dust mass equal to 3.35 times the mass of the Moon.[22] A candidate sub-stellar companion was identified in 2001, but this was determined to be a background object.[23]


  1. ^ a b Byrne, P. B.; et al. (February 1984), "Optical photometry and ultraviolet spectroscopy of the flare/BY DRA star GL 182(V 1005 Ori)", Monthly Notices of the Royal Astronomical Society, 206: 907–918, Bibcode:1984MNRAS.206..907B, doi:10.1093/mnras/206.4.907.
  2. ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. Gaia EDR3 record for this source at VizieR.
  3. ^ a b Kiraga, M. (March 2012), "ASAS Photometry of ROSAT Sources. I. Periodic Variable Stars Coincident with Bright Sources from the ROSAT All Sky Survey", Acta Astronomica, 62 (1): 67–95, Bibcode:2012AcA....62...67K.
  4. ^ a b c Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
  5. ^ a b Torres, C. A. O.; et al. (December 2006), "Search for associations containing young stars (SACY). I. Sample and searching method", Astronomy and Astrophysics, 460 (3): 695–708, arXiv:astro-ph/0609258, Bibcode:2006A&A...460..695T, doi:10.1051/0004-6361:20065602, S2CID 16080025. See the online data.
  6. ^ a b Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  7. ^ a b c d e Fouqué, Pascal; et al. (April 2018), "SPIRou Input Catalogue: global properties of 440 M dwarfs observed with ESPaDOnS at CFHT", Monthly Notices of the Royal Astronomical Society, 475 (2): 1960–1986, arXiv:1712.04490, Bibcode:2018MNRAS.475.1960F, doi:10.1093/mnras/stx3246.
  8. ^ Kiraga, M.; Stepien, K. (June 2007), "Age-Rotation-Activity Relations for M Dwarf Stars", Acta Astronomica, 57: 149–172, arXiv:0707.2577, Bibcode:2007AcA....57..149K.
  9. ^ a b c d e Magaudda, E.; et al. (June 2020), "Relation of X-ray activity and rotation in M dwarfs and predicted time-evolution of the X-ray luminosity", Astronomy & Astrophysics, 638: 14, arXiv:2004.02904, Bibcode:2020A&A...638A..20M, doi:10.1051/0004-6361/201937408, A20.
  10. ^ Lépine, Sébastien; et al. (2013), "A Spectroscopic Catalog of the Brightest (J < 9) M Dwarfs in the Northern Sky", The Astronomical Journal, 145 (4): 102, arXiv:1206.5991, Bibcode:2013AJ....145..102L, doi:10.1088/0004-6256/145/4/102, S2CID 117144290.
  11. ^ a b Gaidos, E.; et al. (September 2014), "Trumpeting M dwarfs with CONCH-SHELL: a catalogue of nearby cool host-stars for habitable exoplanets and life", Monthly Notices of the Royal Astronomical Society, 443 (3): 2561–2578, arXiv:1406.7353, Bibcode:2014MNRAS.443.2561G, doi:10.1093/mnras/stu1313, S2CID 119234492.
  12. ^ a b Dal, Hasan Ali; Evren, Serdar (April 2011), "Rotation Modulations and Distributions of the Flare Occurrence Rates on the Surface of Five UV Ceti Type Stars", Publications of the Astronomical Society of Japan, 63 (2): 427–447, arXiv:1206.5792, Bibcode:2011PASJ...63..427D, doi:10.1093/pasj/63.2.427.
  13. ^ "V1005 Ori", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2022-02-16.
  14. ^ Montes, D.; et al. (November 2001), "Late-type members of young stellar kinematic groups - I. Single stars", Monthly Notices of the Royal Astronomical Society, 328 (1): 45–63, arXiv:astro-ph/0106537, Bibcode:2001MNRAS.328...45M, doi:10.1046/j.1365-8711.2001.04781.x, S2CID 55727428.
  15. ^ a b Donati, J. -F.; et al. (October 2008), "Large-scale magnetic topologies of early M dwarfs", Monthly Notices of the Royal Astronomical Society, 390 (2): 545–560, arXiv:0809.0269, Bibcode:2008MNRAS.390..545D, doi:10.1111/j.1365-2966.2008.13799.x.
  16. ^ Shakhovskaya, N. I. (June 1974), "Photoelectric Observations of the Flare Activity of Red Dwarfs", Information Bulletin on Variable Stars, 897 (1), Bibcode:1974IBVS..897....1S.
  17. ^ Bopp, Bernard W. (June 1974), "Detection of Lithium in the dMle Star Gliese 182", Publications of the Astronomical Society of the Pacific, 86 (511): 281, Bibcode:1974PASP...86..281B, doi:10.1086/129600.
  18. ^ Bopp, B. W.; Espenak, F. (November 1977), "Survey of the BY Draconis syndrome among dMe stars", Astronomical Journal, 82: 916–924, Bibcode:1977AJ.....82..916B, doi:10.1086/112146.
  19. ^ Stelzer, B.; Neuhäuser, R. (2001), Jayawardhana, Ray; Greene, Thomas (eds.), "X-ray Emission and Variability of Young, Nearby Stars", Young Stars Near Earth: Progress and Prospects, ASP Conference Series, San Francisco: Astronomical Society of the Pacific, vol. 244, p. 153, arXiv:astro-ph/0105172, Bibcode:2001ASPC..244..153S, ISBN 1-58381-082-X.
  20. ^ Shulyak, D.; et al. (August 2017), "Strong dipole magnetic fields in fast rotating fully convective stars", Nature Astronomy, 1, arXiv:1801.08571, Bibcode:2017NatAs...1E.184S, doi:10.1038/s41550-017-0184, 0184.
  21. ^ Bondar', N. I.; Katsova, M. M. (December 2020), "Long-term Activity in Photospheres of Low-mass Stars with Strong Magnetic Fields", Geomagnetism and Aeronomy, 60 (7): 942–947, arXiv:2011.09879, Bibcode:2020Ge&Ae..60..942B, doi:10.1134/S0016793220070075.
  22. ^ Lestrade, J. -F.; et al. (December 2006), "Search for cold debris disks around M-dwarfs", Astronomy and Astrophysics, 460 (3): 733–741, arXiv:astro-ph/0609574, Bibcode:2006A&A...460..733L, doi:10.1051/0004-6361:20065873.
  23. ^ Neuhäuser, R.; et al. (2001), Jayawardhana, Ray; Greene, Thomas (eds.), "Young Nearby Stars and a Ground-based Direct Imaging Search for Sub-stellar Companions Around Them - Example: A companion candidate near GJ 182", Young Stars Near Earth: Progress and Prospects, ASP Conference Series, San Francisco: Astronomical Society of the Pacific, vol. 244, p. 295, Bibcode:2001ASPC..244..295N, ISBN 1-58381-082-X.

Further reading

  • Bischoff, Richard; et al. (November 2020), "Identification of young nearby runaway stars based on Gaia data and the lithium test", Astronomische Nachrichten, 341 (9): 908–942, arXiv:2009.02123, Bibcode:2020AN....341..908B, doi:10.1002/asna.202013793.
  • MacTaggart, D.; et al. (February 2016), "Magnetohydrostatic modelling of stellar coronae", Monthly Notices of the Royal Astronomical Society, 456 (1): 767–774, arXiv:1511.06133, Bibcode:2016MNRAS.456..767M, doi:10.1093/mnras/stv2714.
  • Vidotto, A. A.; et al. (February 2014), "M-dwarf stellar winds: the effects of realistic magnetic geometry on rotational evolution and planets", Monthly Notices of the Royal Astronomical Society, 438 (2): 1162–1175, arXiv:1311.5063, Bibcode:2014MNRAS.438.1162V, doi:10.1093/mnras/stt2265.
  • Dal, H. A.; Evren, S. (February 2011), "Saturation Levels for White-light Flares of Flare Stars: Variation of Minimum Flare Duration for Saturation", The Astronomical Journal, 141 (2): 10, arXiv:1206.5793, Bibcode:2011AJ....141...33D, doi:10.1088/0004-6256/141/2/33, 33.
  • Nielsen, Eric L.; et al. (February 2008), "Constraints on Extrasolar Planet Populations from VLT NACO/SDI and MMT SDI and Direct Adaptive Optics Imaging Surveys: Giant Planets are Rare at Large Separations", The Astrophysical Journal, 674 (1): 466–481, arXiv:0706.4331, Bibcode:2008ApJ...674..466N, doi:10.1086/524344.
  • Liu, Michael C.; et al. (June 2004), "A Submillimeter Search of Nearby Young Stars for Cold Dust: Discovery of Debris Disks around Two Low-Mass Stars", The Astrophysical Journal, 608 (1): 526–532, arXiv:astro-ph/0403131, Bibcode:2004ApJ...608..526L, doi:10.1086/392531.
  • Alekseev, I. Yu. (January 1996), "Spottedness of the emission-line dwarfs V775 Her, VY Ari, OU Gem, and V1005 Ori in 1974-1993", Astronomy Reports, 40 (1): 74–80, Bibcode:1996ARep...40...74A.
  • Andrews, A. D. (May 1991), "Investigation of micro-flaring and secular and quasi-periodic variations in dMe flare stars. VII. A revived "planetesimal-impact" hypothesis and the young dM0.5e star, Gliese 182", Astronomy and Astrophysics, 245: 219, Bibcode:1991A&A...245..219A.
  • Mathioudakis, M.; et al. (April 1991), "Rotational modulation and flares on RS Canum Venaticorum and BY Draconis stars. XVI. IUE spectroscopy and VLA observations of GL 182 (=V 1005 Orionis) in October 1983.", Astronomy and Astrophysics, 244: 155, Bibcode:1991A&A...244..155M.
  • Bopp, B. W.; Torres, C. A. O.; Busko, I. C.; Quast, G. R. (June 1978), "Observations of the BY Draconis Variable Gliese 182", Information Bulletin on Variable Stars, 1443 (1), Bibcode:1978IBVS.1443....1B.