NU Pavonis

Not to be confused with Nu (𝜈) Pavonis.

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]

A visual band light curve for NU Pavonis, plotted from data published by Tabur et al. (2009)^[10]

NU Pavonis

Location of NU Pavonis (circled)
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

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.^[11] It was given its variable star designation, NU Pavonis, in 1973.^[12] 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]