HD 210056

HD 210056, also known as HR 8432, is a solitary orange hued star located in the southern circumpolar constellation Octans. Eggen (1993) listed it as a member of the old disk population.^[12]

HD 210056

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Octans
Right ascension	22h 11m 54.98416s[1]
Declination	−76° 06′ 57.6788″[1]
Apparent magnitude (V)	6.13±0.01[2]
Characteristics
Spectral type	K0 III[3]
U−B color index	+0.82[4]
B−V color index	+1.00[4]
Astrometry
Radial velocity (Rv)	24±1[5] km/s
Proper motion (μ)	RA: −59.351 mas/yr[1] Dec.: −40.005 mas/yr[1]
Parallax (π)	11.1656±0.0205 mas
Distance	292.1 ± 0.5 ly (89.6 ± 0.2 pc)
Absolute magnitude (MV)	+1.41[6]
Details[7]
Mass	1.59±0.07 M☉
Radius	7.72±0.13 R☉
Luminosity	29.7±0.5 L☉
Surface gravity (log g)	2.86±0.10 cgs
Temperature	4,849±37 K
Metallicity [Fe/H]	−0.08±0.03 dex
Rotational velocity (v sin i)	<1.5[8] km/s
Age	2.10±0.22[9] Gyr
Other designations
68 G. Octantis[10], CD−76°1120, CPD−76°1549, GC 31004, HD 210056, HIP 109584, HR 8432, SAO 258006[11]
Database references
SIMBAD	data

The object has an apparent magnitude of 6.13,^[2] making it barely visible to the naked eye. Based on parallax measurements from the Gaia satellite, the object is estimated to be 292 light years distant.^[1] It appears to be receding with a heliocentric radial velocity of 24 km/s.^[5] At its current distance, HD 210056's brightness is diminished by 0.2 magnitudes due to interstellar dust. It has an absolute magnitude of +1.41.^[13]

This is an evolved giant star with a stellar classification of K0 III. It has 1.59 times the mass of the Sun but has expanded to 7.72 times its girth.^[7] It radiates 29.7 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,849 K.^[7] Based on asteroseismologic measurements, HD 210056 is estimated to be 2 billion years old.^[9] The star has about 90% of the Sun's metallicity — what astronomers define a star's abundance of chemical elements heavier than helium.^[7] It currently spins slowly with a projected rotational velocity lower than 1.5 km/s.^[9]