Astronomy:Pi Chamaeleontis

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Short description: Star in the constellation Chamaeleon
π Chamaeleontis
Observation data
Equinox J2000.0]] (ICRS)
Constellation Chamaeleon
Right ascension  11h 37m 15.63631s[1]
Declination −75° 53′ 47.5626″[1]
Apparent magnitude (V) 5.64[2]
Characteristics
Spectral type A9 IV[3] or F1 III[4]
U−B color index −0.01[5]
B−V color index +0.35[5]
Astrometry
Radial velocity (Rv)−9.8±3.7[6] km/s
Proper motion (μ) RA: −127.94[1] mas/yr
Dec.: −1.82[1] mas/yr
Parallax (π)24.09 ± 0.33[1] mas
Distance135 ± 2 ly
(41.5 ± 0.6 pc)
Absolute magnitude (MV)2.56[7]
Orbit[1]
Period (P)223.1845±1.9460 d
Semi-major axis (a)7.86±0.83 mas
Eccentricity (e)0.3244±0.1375
Inclination (i)104.88±5.52°
Details
Mass1.52[8] M☉
Radius2.2[9] R☉
Luminosity8[9] L☉
Surface gravity (log g)4.08[8] cgs
Temperature6,853±80[6] K
Metallicity [Fe/H]−0.28[6] dex
Rotational velocity (v sin i)50[10] km/s
Age1.8±0.1[7] Gyr
Other designations
π Cha, CPD−75°744, FK5 438, HD 101132, HIP 56675, HR 4479, SAO 256857[11]
Database references
SIMBADdata

Pi Chamaeleontis, its name Latinized from π Chamaeleontis, is a binary star[12][13] system located in the southern circumpolar constellation of Chamaeleon. It is dimly visible to the naked eye with an apparent visual magnitude of 5.64.[2] Parallax measurements by Hipparcos put the system approximately 135 light-years (41.5 parsecs) away.[1] It is drifting closer with a radial velocity of −10 km/s.[6]

The Hipparcos satellite mission derived a 223 d orbit on the basis of its motion caused by an unseen companion.[1] The visible component is an A-type subgiant[3] or F-type giant star with an effective temperature of about 6,900 K.[6] It has an absolute magnitude of 2.56,[7] a mass of 1.52 M☉,[8] and a radius of 2.2 M☉.[9] It is roughly 1.8 billion years old.[7]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V. 
  2. ↑ 2.0 2.1 Allende Prieto, C.; Lambert, D. L. (1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: masses, radii and effective temperatures". Astronomy and Astrophysics 352: 555–562. Bibcode: 1999A&A...352..555A. 
  3. ↑ 3.0 3.1 Houk, N.; Cowley, A. P. (1975). "University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Volume I. Declinations -90°.0 to -53°.0.". Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars 1. Bibcode: 1975mcts.book.....H. 
  4. ↑ Kharchenko, N. V. (2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ~55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten 328 (9): 889. doi:10.1002/asna.200710776. Bibcode: 2007AN....328..889K. 
  5. ↑ 5.0 5.1 Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory 4: 99. Bibcode: 1966CoLPL...4...99J. 
  6. ↑ 6.0 6.1 6.2 6.3 6.4 Casagrande, L.; Schönrich, R.; Asplund, M.; Cassisi, S.; Ramírez, I.; Meléndez, J.; Bensby, T.; Feltzing, S. (2011). "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey". Astronomy & Astrophysics 530: A138. doi:10.1051/0004-6361/201016276. Bibcode: 2011A&A...530A.138C. 
  7. ↑ 7.0 7.1 7.2 7.3 Holmberg, J.; Nordström, B.; Andersen, J. (2009). "The Geneva-Copenhagen survey of the solar neighbourhood". Astronomy & Astrophysics 501 (3): 941. doi:10.1051/0004-6361/200811191. Bibcode: 2009A&A...501..941H. 
  8. ↑ 8.0 8.1 8.2 Lambert, David L.; Reddy, Bacham E. (2004). "Lithium abundances of the local thin disc stars". Monthly Notices of the Royal Astronomical Society 349 (2): 757. doi:10.1111/j.1365-2966.2004.07557.x. Bibcode: 2004MNRAS.349..757L. 
  9. ↑ 9.0 9.1 9.2 Chandler, Colin Orion; McDonald, Iain; Kane, Stephen R. (2016). "The Catalog of Earth-Like Exoplanet Survey Targets (CELESTA): A Database of Habitable Zones Around Nearby Stars". The Astronomical Journal 151 (3): 59. doi:10.3847/0004-6256/151/3/59. Bibcode: 2016AJ....151...59C. 
  10. ↑ Balachandran, Suchitra (1990). "Lithium depletion and rotation in main-sequence stars". The Astrophysical Journal 354: 310. doi:10.1086/168691. Bibcode: 1990ApJ...354..310B. 
  11. ↑ "pi Cha". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=pi+Cha. 
  12. ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society 389 (2): 869–879. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode: 2008MNRAS.389..869E. 
  13. ↑ Bartkevicius, A.; Gudas, A. (2001). "Kinematics of Hipparcos Visual Binaries. I. Stars with Orbital Solutions". Baltic Astronomy 10 (4): 481–587. doi:10.1515/astro-2001-0402. Bibcode: 2001BaltA..10..481B. 



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