Epsilon Monocerotis

Binary star system in the constellation Monoceros

ε Monocerotis
Observation data Epoch J2000 Equinox
Location of ε Monocerotis (circled red)
Constellation	Monoceros
ε Mon A
Right ascension	06^h 23^m 46.08471^s^[1]
Declination	4° 35′ 34.3153″^[1]
Apparent magnitude (V)	4.39^[2]
ε Mon B
Right ascension	06^h 23^m 46.48292^s^[1]
Declination	4° 35′ 45.2307″^[1]
Apparent magnitude (V)	6.72^[2]
Characteristics
ε Mon A
Spectral type	class = A5 IV^[3]
U−B color index	+0.14^[4]
B−V color index	+0.20^[4]
ε Mon B
Spectral type	F5 V^[3]
U−B color index	−0.05^[5]
B−V color index	+0.45^[5]
Astrometry
ε Mon A
Radial velocity (R_v)	+13.10^[6] km/s
Proper motion (μ)	RA: −22.06^[1] mas/yr Dec.: +10.91^[1] mas/yr
Parallax (π)	26.67 ± 0.90 mas^[1]
Distance	122 ± 4 ly (37 ± 1 pc)
Absolute magnitude (M_V)	1.52^[2]
ε Mon B
Radial velocity (R_v)	+12.40^[6] km/s
Proper motion (μ)	RA: −21.86^[1] mas/yr Dec.: +11.35^[1] mas/yr
Parallax (π)	26.95 ± 0.99 mas^[1]
Distance	121 ± 4 ly (37 ± 1 pc)
Absolute magnitude (M_V)	+3.88^[2]
Details
ε Mon A
Mass	2.04^[7] `M`_☉
Radius	2.5^[8] `R`_☉
Luminosity	25^[7] `L`_☉
Surface gravity (log g)	3.95^[9] cgs
Temperature	7,923^[9] K
Metallicity [Fe/H]	−0.11^[10] dex
Rotational velocity (v sin i)	149^[7] km/s
ε Mon B
Mass	1.16^[8] `M`_☉
Radius	1.1^[8] `R`_☉
Luminosity	2.39^[2] `L`_☉
Surface gravity (log g)	3.95^[9] cgs
Temperature	7,923^[9] K
Rotational velocity (v sin i)	25^[3] km/s
Other designations
ε Mon, 8 Monocerotis, CCDM J06237+0436, WDS J06238+0436
ε Mon A: BD+04° 1236, FK5 244, GC 8240, HD 44769, HIP 30419, HR 2298, SAO 113810
ε Mon B: BD+04° 1237, FK5 244, GC 8241, HD 44770, HIP 30422, HR 2299, SAO 113811
Database references
SIMBAD	data

SIMBAD	data

ε Monocerotis, Latinised as Epsilon Monocerotis, is the Bayer designation of a binary star system in the equatorial constellation Monoceros. Its location is a guide for sky navigation toward the Rosette Nebula.^[11]

The white-hued primary component has a stellar classification of A5 IV,^[3] suggesting it is an aging subgiant star. Its apparent magnitude is 4.39^[2] and it is approximately 122 light years away based on parallax.^[1] It is reportedly a spectroscopic binary with a period around 331 days.^[12]

The B component, at a separation of around 12.3",^[12] is a yellow-white hued F-type main-sequence star of class F5 V^[3] and an apparent magnitude of 6.72.^[2]

References

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600. Vizier catalog entry A Vizier catalog entry B
^ ^a ^b ^c ^d ^e ^f ^g Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644. Vizier catalog entry A Vizier catalog entry B
^ ^a ^b ^c ^d ^e Hoffleit, D.; Warren, W. H. (1995). "VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H. 5050. Bibcode:1995yCat.5050....0H.
^ ^a ^b Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers. 42 (2): 443. Bibcode:2014JAVSO..42..443M.Vizier catalog entry
^ ^a ^b Mermilliod, J. C. (2006). "VizieR Online Data Catalog: Homogeneous Means in the UBV System (Mermilliod 1991)". VizieR On-line Data Catalog: II/168. Originally Published in: Institut d'Astronomie. 2168. Bibcode:2006yCat.2168....0M.Vizier catalog entry
^ ^a ^b Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
^ ^a ^b ^c Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars". Astronomy & Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691. S2CID 55586789. Vizier catalog entry
^ ^a ^b ^c Allende Prieto, C.; Lambert, D. L. (1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: Masses, radii and effective temperatures". Astronomy and Astrophysics. 352: 555–562. arXiv:astro-ph/9911002. Bibcode:1999A&A...352..555A.
^ ^a ^b ^c ^d David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637X/804/2/146. S2CID 33401607.
^ Wu, Yue; Singh, H. P.; Prugniel, P.; Gupta, R.; Koleva, M. (2010). "Coudé-feed stellar spectral library – atmospheric parameters". Astronomy & Astrophysics. 525: A71. arXiv:1009.1491. Bibcode:2011A&A...525A..71W. doi:10.1051/0004-6361/201015014. S2CID 53480665.
^ Kaler, James. "EPS MON (Epsilon Monocerotis)". STARS. University of Illinois. Retrieved 2017-12-23.
^ ^a ^b Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. Vizier catalog entry

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)