NR Canis Majoris
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Canis Major |
| Right ascension | 07h 27m 07.99012s |
| Declination | −17° 51′ 53.5058″ |
| Apparent magnitude (V) | 5.60 (5.66 + 9.23) |
| Characteristics | |
| Spectral type | F2V |
| B−V color index | +0.314±0.002 |
| Variable type | δ Sct |
| Astrometry | |
| Radial velocity (Rv) | −29.2±2.9 km/s |
| Proper motion (μ) | RA: −2.420 mas/yr Dec.: +1.388 mas/yr |
| Parallax (π) | 10.9688±0.0917 mas |
| Distance | 297 ± 2 ly (91.2 ± 0.8 pc) |
| Absolute magnitude (MV) | 0.78 |
| Details | |
| A | |
| Mass | 1.62 or 2.18±0.04 M☉ |
| Radius | 3.90+0.18 −0.24 R☉ |
| Luminosity | 37.4±0.4 L☉ |
| Surface gravity (log g) | 3.65 cgs |
| Temperature | 7,227+238 −160 K |
| Rotational velocity (v sin i) | 185 km/s |
| Age | 1.494 Gyr |
| Other designations | |
| NR CMa, BD−17°1980, HD 58954, HIP 36186, HR 2853, SAO 152894, ADS 6093, CCDM J07271-1752AB, WDS J07271-1752 | |
| Database references | |
| SIMBAD | data |
NR Canis Majoris is a binary star system in the southern constellation of Canis Major, located to the east of Sirius and Gamma Canis Majoris near the constellation border with Puppis. It has a yellow-white hue and is dimly visible to the naked eye with a combined apparent visual magnitude that fluctuates around 5.60. It is located at a distance of approximately 297 light years from the Sun based on parallax. The system is drifting closer to the Sun with a radial velocity of −29 km/s, and in about three million years it is predicted to approach within 14.1+4.7
−4.0 ly. At that time, the star will become the brightest in the night sky, potentially reaching magnitude −0.88.
The magnitude 5.66 primary component is an F-type main-sequence star with a stellar classification of F2V. The star was discovered to be a variable star when the Hipparcos data was analyzed. It was given its variable star designation, NR Canis Majoris, in 1999. It is a Delta Scuti variable that varies by a few hundredths of a magnitude over roughly 16 hours. The star is an estimated 1.5 billion years old. It has a high rate of spin with a projected rotational velocity of 185 km/s, which is giving the star an equatorial bulge that is estimated to be 8% larger than the polar radius.
The secondary companion is magnitude 9.23 and lies at an angular separation of 1.3″ along a position angle of 39°, as of 2005.