R Monocerotis

Variable star in the constellation Monoceros

R Monocerotis
Observation data Epoch J2000 Equinox J2000
R Monocerotis is at the bottom left of this photo. Credit: HST/NASA/JPL
Constellation	Monoceros
Right ascension	06^h 39^m 09.954^s^[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
R Mon, BD+08°1427, 2MASS J06390995+0844097, NGC 2261^[2]
Database references
SIMBAD	data

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]

References

^ ^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.
^ ^a ^b ^c "R Mon". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 26 December 2016.
^ ^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.
^ 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.
^ ^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. S2CID 18763481.
^ "ASAS All Star Catalogue". The All Sky Automated Survey. Retrieved 8 December 2021.
^ 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. S2CID 213902084. 138.

External links

NASA Astronomy Picture of the Day: NGC 2261: Hubble's Variable Nebula (20 October 1999)

Constellation of Monoceros

Stars

Bayer	α β γ δ ε ζ
Flamsteed	1 2 3 6 7 9 10 12 13 14 16 17 18 19 20 21 23 24 25 27 28 77 Ori 78 Ori
Variable	R S (15) T U V RU RW SV TU UX VV VY AO AR AU AX BE BN BT BX CL CS CV CW DD FU GI IM PZ V372 V396 V474 V505 V569 V577 V578 V582 V588 V589 V590 V592 V614 V616 V638 V640 V641 V644 V653 V682 V684 V689 V694 V695 V696 V700 V715 V721 V723 V728 V731 V739 V743 V750 V753 V827 V838 V926
HR	2150 2154 2179 2205 2224 2234 2237 2267 2270 2280 2292 2300 2313 2317 2321 2324 2325 2328 2333 2342 2347 2355 2367 2370 2375 2378 2381 2386 2395 2406 2409 2418 2426 2430 2440 2458 2461 2467 2469 2474 2479 2502 2508 2514 2521 2530 2543 2551 2555 2570 2572 2577 2582 2584 2589 2599 2606 2610 2613 2624 2627 2636 2639 2647 2655 2656 2663 2676 2694 2731 2732 2739 2752 2765 2806 2807 2811 2833 2865 2866 2867 2876 2883 2920 2958 3014 3047 3054 3072 3150 3172 3174 3189
HD	42132 44179 44219 45090 45166 45215 45652 (Lusitânia) 46149 46150 46202 46223 46375 46966 48099 50064 50138 50281 52265 (Citalá) 65938 66428
Other	A0620-00 AFGL 961 CoRoT-1 CoRoT-4 CoRoT-5 CoRoT-7 CoRoT-12 CoRoT-13 CoRoT-14 CoRoT-15 CoRoT-18 CoRoT-19 CoRoT-20 CoRoT-21 CoRoT-24 Gliese 282 Monoceros R2 IRS 3 NGC 2264 IRS 1 Ross 614 Scholz's SCR 0640−0552 UGPS J0652+0324 UGPS J0722−0540

Exoplanets	CoRoT-1b CoRoT-4b CoRoT-5b CoRoT-7b CoRoT-7c CoRoT-7d CoRoT-12b CoRoT-13b CoRoT-14b CoRoT-15b CoRoT-18b CoRoT-19b CoRoT-20b CoRoT-20c CoRoT-21b CoRoT-24b CoRoT-24c HD 44219 b HD 45652 b (Viriato) HD 46375 b HD 52265 b (Cayahuanca)