HD 12039

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HD 12039
Observation data
Epoch J2000      Equinox J2000
Constellation Cetus
Right ascension 01h 57m 48.97842s[1]
Declination −21° 54′ 05.3449″[1]
Apparent magnitude (V) 8.00[2]
Spectral type G4V[2]
Variable type BY Dra
Radial velocity (Rv) +5.7 ± 0.3[3] km/s
Proper motion (μ) RA: +105.08[1] mas/yr
Dec.: −50.60[1] mas/yr
Parallax (π) 24.45 ± 0.67[1] mas
Distance 133 ± 4 ly
(41 ± 1 pc)
Absolute magnitude (MV) 5.03[4][5]
Mass 1.02[6] M
Luminosity 0.89[7] L
Temperature 5,585[4][5] K
Metallicity [Fe/H] -0.28[4][5] dex
Rotational velocity (v sin i) 15.2[8] km/s
Age 7.5−8 × 106[7] years
Other designations
DK Cet, CD−22° 656, HD 12039, SAO 167434, HIP 9141.
Database references

HD 12039 is a variable star in the constellation of Cetus at a distance of about 133 ly (41 pc). It is categorized as a BY Draconis variable because of luminosity changes caused by surface magnetic activity coupled with rotation of the star.[9] The stellar classification G4V is similar to the Sun, indicating this is a main sequence star that is generating energy at its core through the thermonuclear fusion of hydrogen. The effective temperature of 5,585 K[4] gives the star a yellow hue. It has about the same mass as the Sun, but only emits 89% of the Sun's luminosity. This is a young star with age estimates ranging from 7.5−8 million years[10] to 30 million years.[6]

In 2006, a debris field was discovered in orbit around this star using infrared observations by the Spitzer telescope. This debris is thought to be an asteroid belt. The measured temperature of the debris is 110 K, which places it in an orbit between 4 and 6 AU from the star, or about the same distance where Jupiter orbits the Sun.[11] This debris disk may have been created by the breakup of a single, 100 km diameter planetesimal through a collision.[12] The star system does not show any excess emission at 70 μm, indicating it does not have a cold outer dust disk.[13]

The star was examined for the presence of an extrasolar planet with a mass in the range 2-10 Jupiter masses and an orbital distance of 3-15.5 AU. Instead, in 2007, a close stellar companion was likely discovered. This object is separated from the primary by 0.15 arcseconds, making it unlikely to be a background object.[14]

This star has been proposed as a member of the Tucana-Horoglium Association (T-WA), a stream of young stars with a common motion through space. The T-WA association is about 30 million years old.[15][16] The space velocity components of this star are [U, V, W] = [−0.6, −16.3, 5.0] km/s.[10] It is orbiting the Milky Way galaxy with an orbital eccentricity of 0.06, with a distance that varies from 7.11−8.01 kpc of the galactic core. The inclination of its orbit carries it as far as 90 parsecs above the galactic plane.[5]


  1. ^ a b c d e van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. Bibcode:2007A&A...474..653V. arXiv:0708.1752Freely accessible. doi:10.1051/0004-6361:20078357. 
  2. ^ a b Torres, G. R.; et al. (December 2006). "Search for associations containing young stars (SACY). I. Sample and searching method". Astronomy and Astrophysics. 460 (3): 695–708. Bibcode:2006A&A...460..695T. arXiv:astro-ph/0609258Freely accessible. doi:10.1051/0004-6361:20065602. 
  3. ^ Nordström, B.; et al. (2004). "The Geneva-Copenhagen Survey of the Solar Neighbourhood". Publications of the Astronomical Society of Australia. 21 (2): 129–133. Bibcode:2004PASA...21..129N. doi:10.1071/AS04013. 
  4. ^ a b c d Holmberg, J.; Nordstrom, B.; Andersen, J. (July 2009). "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics". Astronomy and Astrophysics. 501 (3): 941–947. Bibcode:2009A&A...501..941H. arXiv:0811.3982Freely accessible. doi:10.1051/0004-6361/200811191. 
  5. ^ a b c d "Detailed Description of V/130". VizieR catalogue service. Centre de Données astronomiques de Strasbourg. Retrieved 2009-09-07. 
  6. ^ a b Weidenschilling, S. J. (October 2010). "Collisional and Luminosity Evolution of a Debris Disk: The Case of HD 12039". The Astrophysical Journal. 722 (2): 1716–1726. Bibcode:2010ApJ...722.1716W. doi:10.1088/0004-637X/722/2/1716 
  7. ^ a b Roccatagliata, V.; et al. (April 2009). "Long-wavelength observations of debris discs around sun-like stars". Astronomy and Astrophysics. 497 (2): 409–421. Bibcode:2009A&A...497..409R. arXiv:0902.0338Freely accessible. doi:10.1051/0004-6361/200811018. 
  8. ^ 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. ^ Kazarovets, A. V.; et al. (1999). "The 74th Special Name-list of Variable Stars". Information Bulletin on Variable Stars. 4659: 1. Bibcode:1999IBVS.4659....1K. 
  10. ^ a b Wichmann, R.; Schmitt, J. H. M. M.; Hubrig, S. (March 2003). "Nearby young stars". Astronomy and Astrophysics. 399 (3): 983–994. Bibcode:2003A&A...399..983W. doi:10.1051/0004-6361:20021867. 
  11. ^ Hines, Dean C.; et al. (February 20, 2006). "The Formation and Evolution of Planetary Systems (FEPS): Discovery of an Unusual Debris System Associated with HD 12039". The Astrophysical Journal. 638 (2): 1070–1079. Bibcode:2006ApJ...638.1070H. arXiv:astro-ph/0510294Freely accessible. doi:10.1086/498929. 
  12. ^ Greaves, Jane; et al. (May 2007). "The composition of debris around HD 12039: water from asteroids?". Spitzer Proposal ID #40310: 40310. Bibcode:2007sptz.prop40310G. 
  13. ^ Klahr, Hubert; Brandner, Wolfgang (2006). Planet formation: theory, observations and experiments. Cambridge University Press. p. 28. ISBN 0-521-86015-6. 
  14. ^ Biller, Beth A.; et al. (November 2007). "An Imaging Survey for Extrasolar Planets around 45 Close, Young Stars with the Simultaneous Differential Imager at the Very Large Telescope and MMT". The Astrophysical Journal Supplement Series. 173 (1): 143–165. Bibcode:2007ApJS..173..143B. doi:10.1086/519925. 
  15. ^ Zuckerman, B.; Song, Inseok (2004). "Young Stars Near the Sun". Annual Review of Astronomy & Astrophysics. 42 (1): 685–721. Bibcode:2004ARA&A..42..685Z. doi:10.1146/annurev.astro.42.053102.134111. 
  16. ^ Makarov, Valeri V. (March 2007). "Unraveling the Origins of Nearby Young Stars". The Astrophysical Journal Supplement Series. 169 (1): 105–119. Bibcode:2007ApJS..169..105M. doi:10.1086/509887. 

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