HR 3384

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HR 3384
Observation data
Epoch J2000      Equinox J2000
Constellation Pyxis
Right ascension 08h 32m 51.49609s[1]
Declination –31° 30′ 03.0717″[1]
Apparent magnitude (V) 6.38[2]
Spectral type G9V[3]
U−B color index +0.29[4]
B−V color index +0.78[4]
Radial velocity (Rv)+81.91[5] km/s
Proper motion (μ) RA: –1113.37[1] mas/yr
Dec.: 761.57[1] mas/yr
Parallax (π)81.91 ± 0.46[1] mas
Distance39.8 ± 0.2 ly
(12.21 ± 0.07 pc)
Absolute magnitude (MV)5.95[2]
Mass0.750±0.015[6] M
Radius0.85[7] R
Luminosity0.44[8] L
Surface gravity (log g)4.56[9] cgs
Temperature5,290[9] K
Metallicity [Fe/H]−0.36[9] dex
Rotation40.2 ± 4.1 d[10]
Rotational velocity (v sin i)6.79[11] km/s
Age5.7–6.5[2] Gyr
Other designations
11 G. Pyxidis, CD−31° 6229, GJ 309, HD 72673, HIP 41926, HR 3384, SAO 199352, LHS 249, LTT 3168
Database references

HR 3384 (11 G. Pyxidis) is solitary star in the southern constellation of Pyxis. It has an apparent magnitude of 6.38,[2] indicating it is faintly visible to the naked eye. Based on the Bortle scale, the star can be viewed from dark rural skies. Astrometric measurements of the star by the Hipparcos spacecraft, give an estimated distance of about 40 light-years (12 parsecs) from Earth. It is moving away from the Sun with a radial velocity of +81.91.[5]

This star is lower in mass than the Sun at around 75%,[6] and has just 85%[7] of the Sun's radius. The spectrum matches a spectral class G9V,[3] indicating that this is a G-type main sequence star that is generating energy through the nuclear fusion of hydrogen at its core. The star is radiating 44%[8] of the Sun's luminosity from its photosphere at an effective temperature of 5,290 K.[9] It is about six[2] billion years old and is rotating slowly with a period of around 40 days. Surface magnetic activity has been detected with a periodic cycle of 3,050+558
 days.[10] HR 3384 has been examined for evidence of a circumstellar debris disk or planets, but, as of 2012, none have been discovered.[12]


  1. ^ a b c d e van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357 Vizier catalog entry
  2. ^ a b c d e Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008), "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics", The Astrophysical Journal, 687 (2): 1264–1293, arXiv:0807.1686Freely accessible, Bibcode:2008ApJ...687.1264M, doi:10.1086/591785 
  3. ^ a b Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770Freely accessible, Bibcode:2006AJ....132..161G, doi:10.1086/504637 
  4. ^ a b Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV data, SIMBAD, Bibcode:1986EgUBV........0M 
  5. ^ a b Nidever, David L.; et al. (August 2002), "Radial Velocities for 889 Late-Type Stars", The Astrophysical Journal Supplement Series, 141 (2): 503–522, arXiv:astro-ph/0112477Freely accessible, Bibcode:2002ApJS..141..503N, doi:10.1086/340570 
  6. ^ a b Tsantaki, M.; et al. (July 2013), "Deriving precise parameters for cool solar-type stars. Optimizing the iron line list", Astronomy & Astrophysics, 555: A150, arXiv:1304.6639Freely accessible, Bibcode:2013A&A...555A.150T, doi:10.1051/0004-6361/201321103. 
  7. ^ 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 (2): 521–524, arXiv:astro-ph/0012289Freely accessible, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451. 
  8. ^ a b Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971Freely accessible. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015.  Vizier catalog entry
  9. ^ a b c d Ramírez, I.; et al. (February 2013), "Oxygen abundances in nearby FGK stars and the galactic chemical evolution of the local disk and halo", The Astrophysical Journal, 764 (1): 78, arXiv:1301.1582Freely accessible, Bibcode:2013ApJ...764...78R, doi:10.1088/0004-637X/764/1/78 
  10. ^ a b Karatas, Y.; Schuster, W. J. (October 2006), "Metallicity and absolute magnitude calibrations for UBV photometry", Monthly Notices of the Royal Astronomical Society, 371 (4): 1793–1812, Bibcode:2006MNRAS.371.1793K, doi:10.1111/j.1365-2966.2006.10800.x. 
  11. ^ Martínez-Arnáiz, R.; et al. (September 2010), "Chromospheric activity and rotation of FGK stars in the solar vicinity. An estimation of the radial velocity jitter", Astronomy and Astrophysics, 520: A79, arXiv:1002.4391Freely accessible, Bibcode:2010A&A...520A..79M, doi:10.1051/0004-6361/200913725 
  12. ^ Maldonado, J.; Eiroa, C.; Villaver, E.; Montesinos, B.; Mora, A. (May 2012), "Metallicity of solar-type stars with debris discs and planets", Astronomy & Astrophysics, 541: 10, arXiv:1202.5884Freely accessible, Bibcode:2012A&A...541A..40M, doi:10.1051/0004-6361/201218800, A40. 

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