19_Monocerotis
19 Monocerotis
Star in the constellation Monoceros
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]
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]