40 Arietis
Binary star in the constellation Aries
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40 Arietis is a probable binary star[3] system in the northern constellation of Aries. 40 Arietis is the Flamsteed designation. Their combined apparent magnitude is 5.82,[2] putting the system near the limit of naked eye visibility. Based upon an annual parallax shift of just 7.33 mas,[1] it is 445 light-years (136 parsecs) away from the Sun. At that distance, its brightness is diminished by 0.21 in magnitude from extinction caused by interstellar gas and dust.[9]
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Aries |
| Right ascension | 02h 48m 32.08864s[1] |
| Declination | +18° 17′ 01.6491″[1] |
| Apparent magnitude (V) | 5.82[2] |
| Characteristics | |
| Spectral type | K1 III[3] |
| U−B color index | 1.13 |
| B−V color index | +1.20[2] |
| R−I color index | 0.44 |
| Variable type | suspected[4] |
| Astrometry | |
| Radial velocity (Rv) | +47.1[5] km/s |
| Proper motion (μ) | RA: +41.250[1] mas/yr Dec.: −32.585[1] mas/yr |
| Parallax (π) | 7.3266±0.1215 mas[1] |
| Distance | 445 ± 7 ly (136 ± 2 pc) |
| Absolute magnitude (MV) | 0.09[6] |
| Details[7] | |
| Mass | 1.60±0.48 M☉ |
| Radius | 19.74+0.29 −0.96[1] R☉ |
| Luminosity | 127.98±2.52[1] L☉ |
| Surface gravity (log g) | 2.09±0.11 cgs |
| Temperature | 4,473±92 K |
| Metallicity [Fe/H] | −0.21±0.05 dex |
| Age | 2.63+1.00 −0.72 Gyr |
| Other designations | |
| 40 Ari, NSV 937, AAVSO 0242+17C, BD+17°442, GC 3369, HD 17459, HIP 13108, HR 828, SAO 93118[8] | |
| Database references | |
| SIMBAD | data |
This is a suspected spectroscopic binary with an angular separation of 0.2″ between the two components.[3] The visible component is an evolved giant star with a stellar classification of K1 III.[3] It is a suspected variable star of unknown type,[4] and is around 2.6 billion years old with 1.6 times the mass of the Sun.[7] With the supply of hydrogen at its core exhausted, the star has expanded to 20 times the Sun's radius.[1] It is radiating 128 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,473 K.[7]