Pi Arietis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aries |
| Right ascension | 02h 49m 17.55924s |
| Declination | +17° 27′ 51.5168″ |
| Apparent magnitude (V) | 5.314 |
| Characteristics | |
| Spectral type | B6 V + A0 V + F8 V |
| U−B color index | −0.47 |
| B−V color index | −0.06 |
| Astrometry | |
| Radial velocity (Rv) | +8.8±0.9 km/s |
| Proper motion (μ) | RA: +2.60 mas/yr Dec.: −14.10 mas/yr |
| Parallax (π) | 4.18±0.69 mas |
| Distance | approx. 800 ly (approx. 240 pc) |
| Absolute magnitude (MV) | −1.56 |
| Details | |
| Mass | 4.4+0.55 −0.51 M☉ |
| Luminosity | 538 L☉ |
| Surface gravity (log g) | 4.5±0.25 cgs |
| Temperature | 16,000±1,000 K |
| Rotational velocity (v sin i) | 70 km/s |
| Age | 13+9 −6 Myr |
| Other designations | |
| π Ari, 42 Arietis, NSV 944, BD+16°355, GC 3378, HD 17543, HIP 13165, HR 836, SAO 93127, PPM 118581 | |
| Database references | |
| SIMBAD | data |
Pi Arietis is a multiple star system in the northern constellation of Aries. Its name is a Bayer designation that is Latinized from π Arietis, and abbreviated Pi Ari or π Ari. Based upon parallax measurements made during the Hipparcos mission, this system is approximately 800 light-years (250 parsecs) distant from Earth, and has an apparent visual magnitude of 5.314. This is bright enough to be faintly seen with the naked eye. The position of this system near the ecliptic means it is subject to lunar occultation.
The primary member of this system is an intermediate-mass, B-type main sequence star with a stellar classification of B6 V. It is a close, single-lined spectroscopic binary with an orbital period of 3.854 days, an eccentricity of 0.04, and a combined visual magnitude of 5.30. At an angular separation of 3.28 arcseconds is a magnitude 8.46 A-type main sequence star with a classification of A0 Vp. Finally, a fourth member of the system is a magnitude 11.0 F-type main sequence star with a classification of F8V at an angular separation of 25.2 arcseconds from the primary.