HD 3322

HD 3322 is a binary star^[8] system in the northern constellation of Andromeda. With an apparent visual magnitude of 6.51,^[3] it lies below the nominal brightness limit for visibility with the normal naked eye, but it is still possible to see the star with excellent vision under ideal seeing conditions. An annual parallax shift of 4.59±0.65 mas^[2] provides a distance estimate of roughly 700 light years.

HD 3322

Ultraviolet, blue and visual band light curves for PY Andromedae, plotted from data published by Catalano and Leone (1991)[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Andromeda
Right ascension	00h 36m 20.09863s[2]
Declination	+27° 15′ 17.1519″[2]
Apparent magnitude (V)	6.51[3]
Characteristics
Evolutionary stage	Main sequence[4]
Spectral type	B8.5 IIIp HgMn[5]
B−V color index	−0.070±0.011[3]
Variable type	α2 CVn[6]
Astrometry
Radial velocity (Rv)	+4.0±7.4[7] km/s
Proper motion (μ)	RA: +15.96[2] mas/yr Dec.: −11.11[2] mas/yr
Parallax (π)	4.59±0.65 mas[2]
Distance	approx. 700 ly (approx. 220 pc)
Absolute magnitude (MV)	−0.13[3]
Orbit[8]
Period (P)	399.6±2.1 d
Eccentricity (e)	0.57±0.09
Periastron epoch (T)	2440462.38 ± 6.05 JD
Argument of periastron (ω) (secondary)	304±11°
Semi-amplitude (K1) (primary)	8.07±1.07 km/s
Details
HD 3322 A
Mass	3.68±0.21[4] M☉
Radius	4.8[9] R☉
Luminosity	246+91 −66[4] L☉
Surface gravity (log g)	3.821±0.056[10] cgs
Temperature	12,882+90 −88[4] K
Rotational velocity (v sin i)	14[4] km/s
Other designations
PY And, BD+26° 91, HD 3322, HIP 2865, HR 149, SAO 74136, PPM 89965[11]
Database references
SIMBAD	data

This is a single-lined spectroscopic binary star system with an orbital period of around 400 days and an eccentricity of 0.57.^[8] The visible component has a stellar classification of B8.5 IIIp HgMn,^[5] matching a chemically peculiar B-type giant mercury-manganese star.^[12] Catalano and Leone (1991) found it to be a α² CVn variable with a period of 4.6904 days,^[1] and thus it received the variable star designation PY And.^[6] It has an estimated 3.7^[4] times the mass of the Sun and about 4.8^[9] times the Sun's radius. It is radiating around 246^[4] times the Sun's luminosity from its photosphere at an effective temperature of 12,882 K.^[4]