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.[2] The star is located at a distance of 71.65 light years from the Sun based on parallax.[1] It is drifting closer with a radial velocity of −3.8 km/s.[1]

HD 45184

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Canis Major
Right ascension	06^h 24^m 43.87975^s[1]
Declination	–28° 46′ 48.4163″[1]
Apparent magnitude (V)	6.37[2]
Characteristics
Evolutionary stage	main sequence
Spectral type	G2Va[3]
Apparent magnitude (B)	6.996[2]
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[2]
Astrometry
Radial velocity (Rv)	−3.828±0.0003[1] km/s
Proper motion (μ)	RA: −165.257[1] mas/yr Dec.: −121.826[1] mas/yr
Parallax (π)	45.5224 ± 0.0320[1] mas
Distance	71.65 ± 0.05 ly (21.97 ± 0.02 pc)
Absolute magnitude (MV)	4.67[2][5]
Details
Mass	1.08±0.04[6] M☉
Radius	1.05±0.02[1] R☉
Luminosity	1.178+0.002 −0.001[1] L☉
Surface gravity (log g)	4.47±0.02[7] cgs
Temperature	5,862+72 −48[1] K
Metallicity [Fe/H]	0.070±0.016[6] dex
Rotation	20.0±0.1 d[6]
Rotational velocity (v sin i)	2.1[7] 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[8]
Database references
SIMBAD	data
Exoplanet Archive	data
Extrasolar Planets Encyclopaedia	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[9]-year magnetic activity cycle that has a lower amplitude than on the Sun.[7]

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.[10] 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.[11] Both Neptune-like planets have near circular orbits close to the host star.[7]

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.[12] 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.[13]

The HD 45184 planetary system[7]

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	—	—

References

1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
2. Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015.
3. Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
4. Cutri, R. M.; et al. (June 2003). 2MASS All Sky Catalog of point sources. NASA/IPAC. Bibcode:2003tmc..book.....C.
5. Datson, Juliet; et al. (March 2014). "Solar analogues and solar twins in the HARPS archive". Monthly Notices of the Royal Astronomical Society. 439 (1): 1028–1037. arXiv:1401.1316. Bibcode:2014MNRAS.439.1028D. doi:10.1093/mnras/stu026.
6. Lorenzo-Oliveira, Diego; et al. (May 2019). "Constraining the evolution of stellar rotation using solar twins". Monthly Notices of the Royal Astronomical Society: Letters. 485 (1): L68–L72. arXiv:1903.02630. Bibcode:2019MNRAS.485L..68L. doi:10.1093/mnrasl/slz034.
7. Udry, S.; et al. (February 2019). "The HARPS search for southern extra-solar planets. XLIV. Eight HARPS multi-planet systems hosting 20 super-Earth and Neptune-mass companions". Astronomy & Astrophysics. 622: 29. arXiv:1705.05153. Bibcode:2019A&A...622A..37U. doi:10.1051/0004-6361/201731173. A37.
8. "HD 45184". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-01-02.
9. Flores, M.; et al. (May 2016). "Discovery of an activity cycle in the solar analog HD 45184. Exploring Balmer and metallic lines as activity proxy candidates". Astronomy & Astrophysics. 589: 6. arXiv:1604.01307. Bibcode:2016A&A...589A.135F. doi:10.1051/0004-6361/201628145. A135.
10. Mayor, M.; et al. (2011). "The HARPS search for southern extra-solar planets XXXIV. Occurrence, mass distribution and orbital properties of super-Earths and Neptune-mass planets". arXiv:1109.2497. Bibcode:2011arXiv1109.2497M. Cite journal requires |journal= (help)
11. Gillon, M.; et al. (2017). "The Spitzer search for the transits of HARPS low-mass planets. II. Null results for 19 planets". Astronomy and Astrophysics. 601. A117. arXiv:1701.01303. Bibcode:2017A&A...601A.117G. doi:10.1051/0004-6361/201629270.
12. Koerner, D. W.; et al. (February 2010). "New Debris Disk Candidates Around 49 Nearby Stars". The Astrophysical Journal Letters. 710 (1): L26–L29. Bibcode:2010ApJ...710L..26K. doi:10.1088/2041-8205/710/1/L26.
13. Cotten, Tara H.; Song, Inseok (July 2016). "A Comprehensive Census of Nearby Infrared Excess Stars". The Astrophysical Journal Supplement Series. 225 (1): 24. arXiv:1606.01134. Bibcode:2016ApJS..225...15C. doi:10.3847/0067-0049/225/1/15. 15.