Astronomy:V380 Orionis

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Short description
Star in the constellation Orion
V380 Orionis
V380 Ori embedded in NGC 1999
Credit: NASA and the Hubble Heritage Team (STScI)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Orion
Right ascension  05h 36m 25.43150s[1]
Declination –06° 42′ 57.6855″[1]
Apparent magnitude (V) 10.2–10.7[2]
Spectral type A1e[3]
Variable type Orion variable[4]
Radial velocity (Rv)15.40[5] km/s
Proper motion (μ) RA: 4.10 ± 3.65[1] mas/yr
Dec.: –3.83 ± 2.62[1] mas/yr
Parallax (π)2.86 ± 5.02[1] mas
Period (P)104 ± 5 days
Semi-amplitude (K1)
< 1.4 km/s
Semi-amplitude (K2)
18 ± 14 km/s
Mass2.87 M
Luminosity100 L
Temperature10,500 ± 500 K
Metallicity [Fe/H]0.5 dex
Rotation4.31276 days
Rotational velocity (v sin i)6.7 ± 1.1 km/s
Mass1.6 M
Luminosity3.16 L
Temperature5,500 ± 500 K
Rotational velocity (v sin i)18.7 ± 3.2 km/s
Age2 ± 1 million Myr
Other designations
V380 Ori, BD−06°1253, HIP 26327, WDS J05365-0643
Database references

V380 Ori is a young multiple star system located near the Orion Nebula in the constellation Orion, thought to be somewhere between 1 and 3 million years old. It lies at the centre of NGC 1999 and is the primary source lighting up this and other nebulae in the region.


V380 Orionis is a multiple star system containing at least three stars. A very faint cool star 9" away is also thought to be gravitationally bound, making it a hierarchical quadruple system. Two infrared sources within NGC 1999 have been listed as companions in some catalogues,[7] but are not thought to be stars.[8] When discovered, they were referred to as V380 Ori-B and V-380 Ori-C,[9] a notation which can lead to confusion.[8]

The main component is visible as the 10th magnitude variable star at the centre of NGC 1999, referred to as the primary. Speckle interferometry shows a cool companion separated by 0.15", approximately 62 AU, referred to as the tertiary. Spectroscopy shows a third star at a projected separation less than 0.33 AU, referred to as the secondary. The two closest stars, the primary and tertiary, are surrounded by a circumstellar disk, lying almost edge-on to observers on earth. The fourth star has a projected separation of 4,000 AU and is receding from the other three.[8]

The system is believed to have formed with all four stars close together, but interacted to eject the smallest star into an unstable but gravitationally bound orbit around 20,000 years ago.[8]

The primary and secondary, the two closest stars, are calculated to orbit every 104 days. The radial velocity signatures in the spectrum have a large margin of uncertainty and the orbit is poorly defined. Comparing the mass ratio found from the orbit with masses assumed from other physical properties suggests that the orbit is seen close to pole-on.[6]


The primary star is a hot white Herbig Ae/Be star that has been variously assigned spectral types between B9 and A1. It has a surface temperature of 10,500 ± 500 K, is around 2.87 times as massive as the sun, 3 times its radius, and 100 times as luminous. It has a strong magnetic field which varies every 4.1 days and this is assumed to be the star's rotation period. Models show that the axis of rotation is inclined at 32 degrees.[6] It is a variable star, considered an Orion variable, with occasional fading and other variability caused by obscuration from the surrounding dust. The apparent magnitude varies irregularly between 10.2 and 10.7.[2] The properties of the star are calculated based on its maximum brightness, assumed to be the least obscured.[6]

The secondary is a T Tauri star, detected by distinctive spectral lines that could not be produced by the hotter primary star. that has a surface temperature of 5,500 ± 500 K, is around 1.6 times as massive as the sun, twice its radius, and three times as luminous.[6]

The nature of the tertiary component is uncertain. No spectral lines have been seen originating from this component.[6]

The fourth star, sometimes called V380 Orionis B, is a small, cool object of spectral type M5 or M6 that is either a red dwarf or brown dwarf.[8]


One of the component stars of V380 Orionis appears to have launched a polar jet that helped to clear the keyhole-shaped hole in the surrounding nebula known as NGC 1999.[10] The system is surrounded by a bow shock—the total structure over 17 light-years (5.3 parsecs) across.[8]


  1. 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode2007A&A...474..653V. Vizier catalog entry
  2. 2.0 2.1 de Winter, D.; van den Ancker, M. E.; Maira, A.; Thé, P. S.; Djie, H. R. E. Tjin A.; Redondo, I. et al. (2001). "A photometric catalogue of southern emission-line stars". Astronomy and Astrophysics 380 (2): 609–14. doi:10.1051/0004-6361:20011476. Bibcode2001A&A...380..609D. 
  3. Manoj, P; Bhatt, H. C; Maheswar, G; Muneer, S (2006). "Evolution of Emission‐Line Activity in Intermediate‐Mass Young Stars". The Astrophysical Journal 653 (1): 657–674. doi:10.1086/508764. Bibcode2006ApJ...653..657M. 
  4. Samus, N. N. et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S 1. Bibcode2009yCat....102025S. 
  5. Turon, C.; Creze, M.; Egret, D.; Gomez, A.; Grenon, M.; Jahreiß, H.; Requieme, Y.; Argue, A. N. et al. (1993). "Version 2 of the HIPPARCOS Input Catalogue". Bulletin d'Information du Centre de Donnees Stellaires 43: 5. Bibcode1993BICDS..43....5T. 
  6. 6.0 6.1 6.2 6.3 6.4 6.5 6.6 Alecian, E.; Wade, G. A.; Catala, C.; Bagnulo, S.; Böhm, T.; Bouret, J.-C. et al. (2009). "Magnetism and binarity of the Herbig Ae star V380 Ori†". Monthly Notices of the Royal Astronomical Society 400 (1): 354–68. doi:10.1111/j.1365-2966.2009.15460.x. Bibcode2009MNRAS.400..354A. 
  7. Mason, B. D. et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal 122 (6): 3466–3471. doi:10.1086/323920. Bibcode2001AJ....122.3466M. 
  8. 8.0 8.1 8.2 8.3 8.4 8.5 Reipurth, Bo; Bally, John; Aspin, Colin; Connelley, M. S.; Geballe, T. R.; Kraus, Stefan et al. (2013). "HH 222: A Giant Herbig-Haro Flow from the Quadruple System V380 Ori". The Astronomical Journal 146 (5): 11. doi:10.1088/0004-6256/146/5/118. 118. Bibcode2013AJ....146..118R. 
  9. Corcoran, D.; Ray, T. P. (1995). "Herbig-Haro outflows in the V 380 Orionis region". Astronomy and Astrophysics 301: 729. Bibcode1995A&A...301..729C. 
  10. "PIA13109: Big Hole Revealed in Infrared". Photojournal. Jet Propulsion Laboratory, California Institute of Technology/NASA. 11 May 2010.