19 Monocerotis is a single,[12] variable star[5] in the equatorial constellation of Monoceros, located approximately 1,220 light years away from the Sun based on parallax.[1] It has the variable star designation V637 Monocerotis, while 19 Monocerotis is the Flamsteed designation. This object is visible to the naked eye as a faint, blue-white hued star with a baseline apparent visual magnitude of 5.00.[2] It is receding from the Earth with a heliocentric radial velocity of +25 km/s.[6]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Monoceros |
Right ascension | 07h 02m 54.77667s[1] |
Declination | −04° 14′ 21.2377″[1] |
Apparent magnitude (V) | 5.00[2] |
Characteristics | |
Spectral type | B2Vn(e)[3]or B1V[4] |
U−B color index | −0.93[2] |
B−V color index | −0.20[2] |
Variable type | β Cep[5] |
Astrometry | |
Radial velocity (Rv) | +24.80[6] km/s |
Proper motion (μ) | RA: −5.05[1] mas/yr Dec.: +2.24[1] mas/yr |
Parallax (π) | 2.68 ± 0.22 mas[1] |
Distance | 1,220 ± 100 ly (370 ± 30 pc) |
Absolute magnitude (MV) | −2.85[7] |
Details | |
Mass | 12.3[8] M☉ |
Radius | 9±3[9] R☉ |
Luminosity | 4,817[7] L☉ |
Surface gravity (log g) | 3.662[10] cgs |
Temperature | 25,400[11] K |
Rotational velocity (v sin i) | 274±3[9] km/s |
Other designations | |
Database references | |
SIMBAD | data |
This massive, B-type main-sequence star has a stellar classification of B1 V.[4] It is a Beta Cephei variable, ranging from 5.01 to 4.96 magnitude with a period of 0.19 days.[5] Closer examination shows there are three frequencies present, consisting of 5.22994, 0.17017, and 4.88956 cycles per day.[9] At one point it was thought to be a marginal Be star, but this was not confirmed.[9] The star is spinning rapidly with a projected rotational velocity of 274 km/s.[9] It has 12.3[8] times the mass of the Sun and is radiating 4,817[7] times the Sun's luminosity from its photosphere at an effective temperature of 25,400 K.[11]