R Monocerotis

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R Monocerotis
Ngc2261.jpg
R Monocerotis is at the bottom left of this photo.
Credit: HST/NASA/JPL
Observation data
Epoch J2000      Equinox J2000
Constellation Monoceros
Right ascension 06h 39m 09.954s[1]
Declination +08° 44′ 09.56″[1]
Apparent magnitude (V) 11.85[2]
Characteristics
Spectral type B8IIIev[3]
Variable type T Tauri[2]
Astrometry
Distance2600 ly
(800[4] pc)
Details
Mass~2–10[5] M☉
Age~105 yr[5] years
Other designations
R Mon, BD+08°1427, 2MASS J06390995+0844097, NGC 2261[2]
Database references
SIMBADdata

R Monocerotis, abbreviated R Mon, is a very young binary star[5] system in the equatorial constellation of Monoceros. The apparent magnitude of R Mon varies between 10 and 12 and the spectral type is B8IIIe.[3] However, it is more likely of a late B- or early A-type.[6]

A visual band light curve for R Monocerotis, plotted from ASAS data[7]

This is a massive Herbig Ae/Be star, a type of pre-main-sequence star that is surrounded by an orbiting circumstellar disk of gas and dust. This disk has a mass of ~0.007 M☉ and extends outward to a distance of under 150 AU from the host. Because of this dust, the star is obscured from direct visual sight but can still be observed in the infrared.[5] R Mon is still in the accretion phase of star formation and it is driving an optically opaque bipolar outflow with a velocity of 9 km/s. The northern flow is blue-shifted, and thus moving more toward the Sun.[6] There is a T Tauri-type stellar companion at an angular separation of 0.69″ from the primary.[5]

This system is located in a diffuse nebula called "Hubble's Variable Nebula" (NGC 2261), which is being illuminated by a conical beam of light from the primary.[5] According to some astronomers, the "star" R Monocerotis is not more than a very bright concentration of gases within the nebula, and some sky catalogues and atlases do not even list it as a star.[citation needed]

References[]

  1. ^ a b Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c "R Mon". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 26 December 2016.
  3. ^ a b Mora, A.; et al. (2001). "EXPORT: Spectral classification and projected rotational velocities of Vega-type and pre-main sequence stars". Astronomy and Astrophysics. 378: 116–131. Bibcode:2001A&A...378..116M. doi:10.1051/0004-6361:20011098.
  4. ^ Manoj, P. (2006). "Evolution of Emission-Line Activity in Intermediate-Mass Young Stars". The Astrophysical Journal. 653 (1): 657–674. arXiv:astro-ph/0608541. Bibcode:2006ApJ...653..657M. doi:10.1086/508764. S2CID 17545474.
  5. ^ a b c d e f Fuente, A.; et al. (October 2006). "A Keplerian Gaseous Disk around the B0 Star R Monocerotis". The Astrophysical Journal. 649 (2): L119–L122. arXiv:gr-qc/0608088. Bibcode:2006ApJ...649L.119F. doi:10.1086/508349.
  6. ^ a b Sandell, Göran; et al. (February 2020). "The Molecular Outflow from R Mon". The Astrophysical Journal. 889 (2): 9. Bibcode:2020ApJ...889..138S. doi:10.3847/1538-4357/ab6593. 138.
  7. ^ "ASAS All Star Catalogue". The All Sky Automated Survey. Retrieved 8 December 2021.

Further reading[]

  • Murakawa, K.; et al. (September 2008). "VLT/NACO and Subaru/CIAO JHK-band high-resolution imaging polarimetry of the Herbig Be star R Monocerotis". Astronomy and Astrophysics. 488 (3): L75–L78. Bibcode:2008A&A...488L..75M. doi:10.1051/0004-6361:200810462.</ref>

External links[]

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