HD 44594

From Wikipedia, the free encyclopedia
Jump to: navigation, search
HD 44594
Observation data
Epoch J2000      Equinox J2000
Constellation Puppis
Right ascension 06h 20m 06.13530s[1]
Declination −48° 44′ 27.9344″[1]
Apparent magnitude (V) 6.64[2]
Spectral type G1.5V[3]
U−B color index +0.20[2]
B−V color index +0.66[2]
Radial velocity (Rv) +59.1[4] km/s
Proper motion (μ) RA: +234.60[1] mas/yr
Dec.: −267.31[1] mas/yr
Parallax (π) 39.79 ± 0.34[1] mas
Distance 82.0 ± 0.7 ly
(25.1 ± 0.2 pc)
Absolute magnitude (MV) 4.56[4]
Mass 1.08[5] M
Radius 1.0[6] R
Surface gravity (log g) 4.38[7] cgs
Temperature 5,840[7] K
Metallicity [Fe/H] +0.15[7] dex
Rotational velocity (v sin i) 4.4[8] km/s
Age 4.1[5] Gyr
Other designations
HR 2290, CD-48 2259, HD 44594, LTT 2525, SAO 217861, FK5 2486, HIP 30104.[9]

HD 44594 is a star in the southern constellation Puppis. It has an apparent visual magnitude of 6.64, so it can be seen with the naked eye from the southern hemisphere under good viewing conditions. Based upon parallax measurements, it is located at a distance of about 82 light-years (25 parsecs) from the Earth,[1] giving it an absolute magnitude of 4.56.[4]

Measurement of the star's spectrum show it to match a stellar classification of G1.5V,[3] which is close to the Sun's spectral class of G2V. In the wavelength range 3200–8800 Â, the energy emission of this star is very similar to the Sun, and thus it is considered a solar analog.[10] The luminosity class 'V' means this is a main sequence star that is generating energy through the thermonuclear fusion of hydrogen at its core. The effective temperature of the outer envelope of HD 44594 is 5,840 K,[7] which is giving it the characteristic yellow hue of a G-type star.[11]

This star has about 108%[5] of the Sun's mass and is about the same radius as the Sun.[6] It may be slightly younger than the Sun with an estimated age of 4.1 billion years.[5] the abundance of elements other than hydrogen or helium, what astronomers term the star's metallicity, is 41% higher than in the Sun.[12] The projected rotational velocity of the star is 4.4 km s−1,[8] which gives the minimum azimuthal velocity along the star's equator.

This star has been examined in the infrared using the Spitzer Space Telescope. However, no excess emission was discovered, which might otherwise have indicated the presence of a circumstellar debris disk of orbiting dust.[13]


  1. ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752free to read, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357 
  2. ^ a b c Przybylski, A.; Kennedy, P. M. (1965), "Radial velocities and three-colour photometry of 166 southern stars", Monthly Notices of the Royal Astronomical Society, 131: 95–104, Bibcode:1965MNRAS.131...95P, doi:10.1093/mnras/131.1.95 
  3. ^ a b Gray, R. O.; et al. (October 2003), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I.", The Astronomical Journal, 126 (4): 2048–2059, arXiv:astro-ph/0308182free to read, Bibcode:2003AJ....126.2048G, doi:10.1086/378365 
  4. ^ a b c Nordström, B.; et al. (May 2004), "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs", Astronomy and Astrophysics, 418 (3): 989–1019, arXiv:astro-ph/0405198free to read, Bibcode:2004A&A...418..989N, doi:10.1051/0004-6361:20035959 
  5. ^ a b c d Sousa, S. G.; Fernandes, J.; Israelian, G.; Santos, N. C. (March 2010), "Higher depletion of lithium in planet host stars: no age and mass effect", Astronomy and Astrophysics, 512: L5, arXiv:1003.0405free to read, Bibcode:2010A&A...512L...5S, doi:10.1051/0004-6361/201014125 
  6. ^ a b Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics, 367: 521–524, arXiv:astro-ph/0012289free to read, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451 
  7. ^ a b c d Sousa, S. G.; et al. (August 2008), "Spectroscopic parameters for 451 stars in the HARPS GTO planet search program. Stellar [Fe/H] and the frequency of exo-Neptunes", Astronomy and Astrophysics, 487 (1): 373–381, arXiv:0805.4826free to read, Bibcode:2008A&A...487..373S, doi:10.1051/0004-6361:200809698 
  8. ^ a b Schröder, C.; Reiners, A.; Schmitt, J. H. M. M. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo", Astronomy and Astrophysics, 493 (3): 1099–1107, Bibcode:2009A&A...493.1099S, doi:10.1051/0004-6361:200810377 
  9. ^ "LTT 2525 – High proper-motion Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2008-05-16 
  10. ^ Hardorp, J.; Tueg, H.; Schmidt-Kaler, T. (March 1982), "The sun among the stars. VI – The solar analog HD 44594", Astronomy and Astrophysics, 107 (2): 311–312, Bibcode:1982A&A...107..311H 
  11. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, retrieved 2012-01-16 
  12. ^ For a metallicity of [Fe/H] = +0.15 dex, the proportion of heavier elements relative to the abundance in the Sun is given by:
    10+0.15 = 1.4
  13. ^ Lawler, S. M.; et al. (November 2009), "Explorations Beyond the Snow Line: Spitzer/IRS Spectra of Debris Disks Around Solar-type Stars", The Astrophysical Journal, 705 (1): 89–111, arXiv:0909.0058free to read, Bibcode:2009ApJ...705...89L, doi:10.1088/0004-637X/705/1/89