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]
Observation data Epoch J2000 Equinox | |
---|---|
Constellation | Monoceros |
ε Mon A | |
Right ascension | 06h 23m 46.08471s[1] |
Declination | 4° 35′ 34.3153″[1] |
Apparent magnitude (V) | 4.39[2] |
ε Mon B | |
Right ascension | 06h 23m 46.48292s[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 (Rv) | +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 (MV) | 1.52[2] |
ε Mon B | |
Radial velocity (Rv) | +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 (MV) | +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 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 |
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]