R Monocerotis

R Monocerotis

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]

A visual band light curve for R Monocerotis, plotted from ASAS data[6]

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.[7] 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]

  1. ^ a b Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Mora_et_al_2001 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Manoj2006 was invoked but never defined (see the help page).
  5. ^ a b c d e f Cite error: The named reference Fuente_et_al_2006 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference ASASServer was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Sandell_et_al_2020 was invoked but never defined (see the help page).