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]](http://upload.wikimedia.org/wikipedia/commons/thumb/c/c6/RMonLightCurve.png/220px-RMonLightCurve.png)
| 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 | |
| Distance | 2600 ly (800[4] pc) |
| Details | |
| Mass | ~2–10[5] M☉ |
| Age | ~105 yr[5] years |
| Other designations | |
| Database references | |
| SIMBAD | data |
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]
Stars of Monoceros | |
|---|---|
| Bayer | |
| Flamsteed | |
| Variable | |
| HR |
|
| HD |
|
| Gliese | |
| Other |
|
| Former | |