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  06h 24m 43.87975s[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
Distance71.65 ± 0.05 ly
(21.97 ± 0.02 pc)
Absolute magnitude (MV)4.67[2][5]
Details
Mass1.08±0.04[6] M☉
Radius1.05±0.02[1] R☉
Luminosity1.178+0.002
−0.001[1] L☉
Surface gravity (log g)4.47±0.02[7] cgs
Temperature5,862+72
−48[1] K
Metallicity [Fe/H]0.070±0.016[6] dex
Rotation20.0±0.1 d[6]
Rotational velocity (v sin i)2.1[7] km/s
Age3.0+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
SIMBADdata
Exoplanet Archivedata
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		 — —
gollark: Possibly. As far as I know medicine courses also are pretty small in size and significantly more government-regulated/managed than other ones.
gollark: Well, sure, the maximum is higher, median is about the same.
gollark: Also, economics isn't MUCH higher, these are box plots.
gollark: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/718225/SFR_18_2017_LEO_mainText.pdfHere is some slightly older data.
gollark: Anyway, the issue with making stuff mandatory at school and stuff is that it will often end up just making people learn how to run the algorithms and whatnot enough to pass exams rather than creating actual understanding and ability to solve practical problems.

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.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.