Megrez
Megrez /ˈmiːɡrɛz/, also called Delta Ursae Majoris (δ Ursae Majoris, abbreviated Delta UMa, δ UMa), is a star in the northern constellation of Ursa Major. With an apparent magnitude of +3.3, it is the dimmest of the seven stars in the Big Dipper asterism. Parallax measurements yield a distance estimate of 80.5 light-years (24.7 parsecs) from the Sun.
Location of δ Ursae Majoris (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ursa Major |
| Right ascension | 12h 15m 25.56063s |
| Declination | +57° 01′ 57.4156″ |
| Apparent magnitude (V) | +3.312 |
| Characteristics | |
| Spectral type | A3 V |
| U−B color index | +0.067 |
| B−V color index | +0.075 |
| Astrometry | |
| Radial velocity (Rv) | -20.2 km/s |
| Proper motion (μ) | RA: +104.11 mas/yr Dec.: 7.30 mas/yr |
| Parallax (π) | 40.51 ± 0.15 mas |
| Distance | 80.5 ± 0.3 ly (24.69 ± 0.09 pc) |
| Absolute magnitude (MV) | +1.39 |
| Details | |
| Mass | 1.63 M☉ |
| Radius | 1.4 R☉ |
| Luminosity | 14 L☉ |
| Surface gravity (log g) | 4.49 cgs |
| Temperature | 9,480±570 K |
| Rotational velocity (v sin i) | 233 km/s |
| Age | 0.3 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.