Pi Chamaeleontis

Pi Chamaeleontis, its name Latinized from π Chamaeleontis, is a binary star^[12][13] system located in the southern circumpolar constellation of Chamaeleon. It is dimly visible to the naked eye with an apparent visual magnitude of 5.64.^[2] Parallax measurements by Hipparcos put the system approximately 135 light-years (41.5 parsecs) away.^[1] It is drifting closer with a radial velocity of −10 km/s.^[6]

π Chamaeleontis

Observation data Epoch J2000      Equinox J2000
Constellation	Chamaeleon
Right ascension	11h 37m 15.63631s[1]
Declination	−75° 53′ 47.5626″[1]
Apparent magnitude (V)	5.64[2]
Characteristics
Spectral type	A9 IV[3] or F1 III[4]
U−B color index	−0.01[5]
B−V color index	+0.35[5]
Astrometry
Radial velocity (Rv)	−9.8±3.7[6] km/s
Proper motion (μ)	RA: −127.94[1] mas/yr Dec.: −1.82[1] mas/yr
Parallax (π)	24.09±0.33 mas[1]
Distance	135 ± 2 ly (41.5 ± 0.6 pc)
Absolute magnitude (MV)	2.56[7]
Orbit[1]
Period (P)	223.1845±1.9460 d
Semi-major axis (a)	7.86±0.83 mas
Eccentricity (e)	0.3244±0.1375
Inclination (i)	104.88±5.52°
Details
Mass	1.52[8] M☉
Radius	2.2[9] R☉
Luminosity	8[9] L☉
Surface gravity (log g)	4.08[8] cgs
Temperature	6,853±80[6] K
Metallicity [Fe/H]	−0.28[6] dex
Rotational velocity (v sin i)	50[10] km/s
Age	1.8±0.1[7] Gyr
Other designations
π Cha, CPD−75°744, FK5 438, HD 101132, HIP 56675, HR 4479, SAO 256857[11]
Database references
SIMBAD	data

The Hipparcos satellite mission derived a 223 d orbit on the basis of its motion caused by an unseen companion.^[1] The visible component is an A-type subgiant^[3] or F-type giant star with an effective temperature of about 6,900 K.^[6] It has an absolute magnitude of 2.56,^[7] a mass of 1.52 M_☉,^[8] and a radius of 2.2 M_☉.^[9] It is roughly 1.8 billion years old.^[7]