NU Pavonis
Red giant star in the constellation Pavo
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NU Pavonis (N-U, not "nu") is a variable star in the southern constellation of Pavo. With an apparent visual magnitude of about 5, it is a faint star but visible to the naked eye. The distance to NU Pav, as determined from its annual parallax shift of 6.9 mas[1] as seen from Earth's orbit, is around 480 light years. It is moving closer with a heliocentric radial velocity of −10 km/s.[5]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pavo[1] |
| Right ascension | 20h 01m 44.74541s[1] |
| Declination | −59° 22′ 33.2173″[1] |
| Apparent magnitude (V) | 4.91 – 5.26[2] |
| Characteristics | |
| Evolutionary stage | AGB[3] |
| Spectral type | M6 III[4] |
| B−V color index | 1.356±0.011[1] |
| Variable type | SRb[2] |
| Astrometry | |
| Radial velocity (Rv) | −10.3±2.8[5] km/s |
| Proper motion (μ) | RA: +20.22[1] mas/yr Dec.: −27.05[1] mas/yr |
| Parallax (π) | 6.86±0.26 mas[1] |
| Distance | 480 ± 20 ly (146 ± 6 pc) |
| Absolute magnitude (MV) | −0.86[1] |
| Details | |
| Mass | 3.7[6] M☉ |
| Radius | 204±29[7] R☉ |
| Luminosity | 5,720±960[7] L☉ |
| Surface gravity (log g) | 0.87[8] cgs |
| Temperature | 3,516±275[7] K |
| Metallicity [Fe/H] | −0.28[6] dex |
| Other designations | |
| NU Pav, CD−59°7361, FK5 3598, HD 189124, HIP 98608, HR 7625, SAO 246389[9] | |
| Database references | |
| SIMBAD | data |
It was designated Lambda2 Indi (λ2 Ind) by Nicolas Louis de Lacaille before its designation was dropped.[10]
This is an aging red giant with a stellar classification of M6 III,[4] currently on the asymptotic giant branch. Peter M. Corben listed HR 7625 as a possible variable star in 1971.[12] It was given its variable star designation, NU Pavonis, in 1973.[13] It is a semiregular variable star of sub-type SRb that ranges in magnitude from 4.91 down to 5.26 with a period of 60 days.[7] The star has expanded to 204 times the Sun's radius[7] and is radiating 7,412 times the Sun's luminosity from its enlarged photosphere[1] at an effective temperature of 3,516 K.[7]
Far-ultraviolet emission has been detected from the position of this star, which may be coming from a companion star.[8]