HD 45184

HD 45184 is a star in the southern constellation of Canis Major. It is a yellow-hued star near the lower limit of visibility to the naked eye with an apparent visual magnitude of 6.37.^[1] The star is located at a distance of 71.4 light years from the Sun based on parallax.^[2] It is drifting closer with a radial velocity of −3.8 km/s.^[2]

HD 45184

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Canis Major[1]
Right ascension	06h 24m 43.87951s[2]
Declination	−28° 46′ 48.4157″[2]
Apparent magnitude (V)	6.37[1]
Characteristics
Evolutionary stage	main sequence[2]
Spectral type	G2Va[3]
Apparent magnitude (B)	6.996[1]
Apparent magnitude (J)	5.219[4]
Apparent magnitude (H)	4.962[4]
Apparent magnitude (K)	4.871[4]
B−V color index	0.626±0.007[1]
Astrometry
Radial velocity (Rv)	−3.85±0.12[2] km/s
Proper motion (μ)	RA: −165.122[2] mas/yr Dec.: −121.852[2] mas/yr
Parallax (π)	45.6782±0.0166 mas[2]
Distance	71.40 ± 0.03 ly (21.892 ± 0.008 pc)
Absolute magnitude (MV)	4.67[1][5]
Details
Mass	1.08±0.04[6] M☉
Radius	1.05±0.04[7] R☉
Luminosity	1.17±0.03[7] L☉
Surface gravity (log g)	4.47±0.02[8] cgs
Temperature	5,854±107[7] K
Metallicity [Fe/H]	0.070±0.016[6] dex
Rotation	20.0±0.1 d[6]
Rotational velocity (v sin i)	2.1[8] km/s
Age	3.0+0.7 −1.4[6] Gyr
Other designations
CD−29°2981, GJ 3394, HD 45184, HIP 30503, HR 2318, SAO 171711, PPM 250356[9]
Database references
SIMBAD	data
Exoplanet Archive	data

This object is an ordinary G-type main-sequence star with a stellar classification of G2Va,^[3] and it is considered a solar twin.^[5] The mass, size, and luminosity of the star are slightly higher than for the Sun, and it has a near solar metallicity – what astronomers term the abundance of elements with higher atomic numbers than helium. The star is around three billion years old and is spinning with a 20-day period.^[6] It has a 5.14^[10]-year magnetic activity cycle that has a lower amplitude than on the Sun.^[8]

Planetary system

HD 45184 has a planet around 12 times as massive as Earth that takes 5.88 days to complete an orbit around its host star. This planet was detected using the radial velocity method.^[11] It was later confirmed with Spitzer, whereupon a second candidate planet of similar mass was discovered orbiting with a 13.1 day period. The star was observed by Spitzer for a transit of the inner planet, but no event was detected.^[12] Both Neptune-like planets have near circular orbits close to the host star.^[8]

An infrared excess has been detected using the Multiband Imaging Photometer for Spitzer at a wavelength of 70 μm, making this a debris disk candidate.^[13] Based upon blackbody models, it is orbiting 1.0 AU from the host star with a mean temperature of 280 K. There may be an additional, 60 K debris disk orbiting at a distance of 22.89 AU.^[14]

The HD 45184 planetary system^[8]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	≥12.19+1.06 −1.03 M🜨	0.0644+0.0020 −0.0021	5.8854±0.0003	0.07±0.05	—	—
c	≥8.81+1.09 −1.02 M🜨	0.1100+0.0034 −0.0036	13.1354+0.0026 −0.0025	0.07+0.07 −0.05	—	—