HD 47536

HD 47536 is a single^[9] star in the southern constellation of Canis Major. It has an orange hue and is dimly visible to the naked eye with an apparent visual magnitude of +5.25.^[1] The star is located at a distance of approximately 408 light years from the Sun based on parallax. It is drifting further away with a radial velocity of 80 km/s.^[2]

HD 47536

Sky area of 10 x 10 square arcmin around the 6th-magnitude giant star HD 47536. Reproduced from the Digital Sky Survey.
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Canis Major[1]
Right ascension	06h 37m 47.61811s[2]
Declination	−32° 20′ 23.0405″[2]
Apparent magnitude (V)	+5.25[1]
Characteristics
Evolutionary stage	red giant branch[3]
Spectral type	K1 III[4]
B−V color index	+1.177±0.002[1]
Astrometry
Radial velocity (Rv)	+79.64±0.13[2] km/s
Proper motion (μ)	RA: +107.755±0.053 mas/yr[2] Dec.: +65.122±0.059 mas/yr[2]
Parallax (π)	7.9902±0.0535 mas[2]
Distance	408 ± 3 ly (125.2 ± 0.8 pc)
Absolute magnitude (MV)	−0.17±0.15[5]
Details[5]
Mass	0.94±0.06 M☉
Radius	23.08+0.68 −0.81[6] R☉
Luminosity	177.2±2.3[6] L☉
Surface gravity (log g)	1.72±0.08 cgs
Temperature	4,384+79 −64[6] K
Metallicity [Fe/H]	−0.68 dex
Rotation	625 days[7]
Rotational velocity (v sin i)	1.93±0.50[3] km/s
Age	9.33±1.88 Gyr
Other designations
CD−32°3216, HD 47536, HIP 31688, HR 2447, SAO 197019, GSC 07091-01257[8]
Database references
SIMBAD	data

This is an aging, metal-poor giant star with a stellar classification of K1 III.^[4] It is about 9.3 billion years old with 94% of the mass of the Sun. Having exhausted the supply of hydrogen at its core, the star cooled and expanded to 23 times the Sun's radius.^[6] The star is spinning slowly, taking 1.71 years to complete its sidereal rotation. It is radiating 177^[6] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,384 K.^[6] As of 2015, at least one planet is known to orbit this star.^[10]

Planetary system

A planetary companion to this star, HD 47536 b, was discovered in 2003 by a team led by J. Setiawan.^[11][3] A second planet, HD 47536 c, was claimed in 2007.^[12] However, a follow-up study by Soto et al. in 2015 failed to detect the signal of the second planet, so it remains unconfirmed.^[10]

The HD 47536 planetary system^[10]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	≥4.0±0.4 MJ	1.12±0.005	434.9±2.6	0.3±0.1	—	—
c (unconfirmed)	>6.98 MJ	3.72	2500	—	—	—

See also

• HD 122430
• List of extrasolar planets