3 Monocerotis is a binary star[3] system in the equatorial constellation of Monoceros, located approximately 780 light years away from the Sun based on parallax.[1] It is visible to the naked eye as a faint, blue-white hued star with a combined apparent visual magnitude of 4.92.[2] The system is moving further from the Earth with a heliocentric radial velocity of +39 km/s.[6]
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Monoceros |
| Right ascension | 06h 01m 50.42241s[1] |
| Declination | −10° 35′ 52.5565″[1] |
| Apparent magnitude (V) | 4.92[2] (4.98 + 8.25)[3] |
| Characteristics | |
| Spectral type | B5 III[4] |
| U−B color index | −0.58[5] |
| B−V color index | −0.12[5] |
| Astrometry | |
| Radial velocity (Rv) | +39.00[6] km/s |
| Absolute magnitude (MV) | −1.94[2] |
| A | |
| Proper motion (μ) | RA: −8.282[7] mas/yr Dec.: 4.385[7] mas/yr |
| Parallax (π) | 4.5717 ± 0.3115 mas[7] |
| Distance | 710 ± 50 ly (220 ± 10 pc) |
| B | |
| Proper motion (μ) | RA: 6.990[8] mas/yr Dec.: 4.574[8] mas/yr |
| Parallax (π) | 3.1006 ± 0.0960 mas[8] |
| Distance | 1,050 ± 30 ly (323 ± 10 pc) |
| Details | |
| 3 Mon A | |
| Mass | 5.85[9] M☉ |
| Radius | 4.5[10] R☉ |
| Luminosity | 1,105[2] L☉ |
| Temperature | 15,000[9] K |
| Metallicity [Fe/H] | 0.00[11] dex |
| Rotational velocity (v sin i) | 45[12] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
The magnitude 4.98 primary, designated component A, has a stellar classification of B5 III,[4] matching an evolved blue giant star. It has 5.85[9] times the mass of the Sun and is radiating 1,105[2] times the Sun's luminosity from its photosphere at an effective temperature of 15,000 K.[9] The companion, component B, is magnitude 7.96 with an angular separation of 1.9″ from the primary.[14]