Astronomy:Pi2 Doradus

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Short description: G-type giant in the constellation Dorado


π2 Doradus
Location of π2 Doradus on the map (circled)
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Dorado
Right ascension  06h 25m 28.63069s[1]
Declination −69° 42′ 25.0800″[1]
Apparent magnitude (V) 5.38[2]
Characteristics
Evolutionary stage horizontal branch[3]
Spectral type G8 III[4]
U−B color index +0.67[2]
B−V color index +0.97[2]
Astrometry
Radial velocity (Rv)9.1±2.8[5] km/s
Proper motion (μ) RA: −12.184[1] mas/yr
Dec.: +200.786[1] mas/yr
Parallax (π)11.7563 ± 0.058[1] mas
Distance277 ± 1 ly
(85.1 ± 0.4 pc)
Absolute magnitude (MV)+0.78[6]
Details[7]
Mass1.80±0.07 M
Radius9.84±0.16 R
Luminosity51.1±1.1 L
Surface gravity (log g)2.66±0.08 cgs
Temperature4,919±29 K
Metallicity [Fe/H]−0.26±0.03 dex
Rotational velocity (v sin i)<2.0[8] km/s
Age1.61±0.15[9] Gyr
Other designations
π2 Dor, CD−69°392, CPD−69°614, FK5 2495, GC 8390, HD 46116, HIP 30565, HR 2327, SAO 249550[10]
Database references
SIMBADdata

Pi2 Doradus, Latinized from π2 Doradus, is a solitary star[11] located in the southern constellation Doradus. It is faintly visible to the naked eye as a yellow-hued point of light with an apparent magnitude of 5.38.[2] The object is located relatively close at a distance of 277 light-years based on Gaia DR3 parallax measurements, but it is receding with a heliocentric radial velocity of approximately 9.1 km/s.[5] At its current distance, Pi2 Doradus' brightness is diminished by 0.27 magnitudes due to interstellar extinction[12] and it has an absolute magnitude of +0.78.[6]

Pi2 Doradus has a stellar classification of G8 III,[4] indicating that it is an evolved G-type giant star. It is a red clump star that is currently on the horizontal branch—fusing helium at its stellar core.[3] It has 1.8 times the mass of the Sun[7] but, at the age of 1.61 billion years,[9] it has expanded to 9.84 times the radius of the Sun.[7] It radiates 51.1 times the luminosity of the Sun from its photosphere at an effective temperature of 4,919 K[7] Pi2 Doradus is metal deficient with an iron abundance of [Fe/H] = −0.26 or roughly 55% of the Sun's.[7] Like many giant stars Pi2 Doradus spins slowly, having a projected rotational velocity lower than km/s.[8]

References

  1. 1.0 1.1 1.2 1.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. 2.0 2.1 2.2 2.3 Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory 4: 99–110. Bibcode1966CoLPL...4...99J. 
  3. 3.0 3.1 Laney, C. D.; Joner, M. D.; Pietrzyński, G. (11 November 2011). "A new Large Magellanic Cloud K-band distance from precision measurements of nearby red clump stars". Monthly Notices of the Royal Astronomical Society 419 (2): 1637–1641. doi:10.1111/j.1365-2966.2011.19826.x. ISSN 0035-8711. Bibcode2012MNRAS.419.1637L. 
  4. 4.0 4.1 Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars: Declinations −90° to −53°. 1. Bibcode1975mcts.book.....H. 
  5. 5.0 5.1 Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35,495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. ISSN 1063-7737. Bibcode2006AstL...32..759G. 
  6. 6.0 6.1 Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331–346. doi:10.1134/S1063773712050015. ISSN 1063-7737. Bibcode2012AstL...38..331A. 
  7. 7.0 7.1 7.2 7.3 7.4 Ottoni, G.; Udry, S.; Ségransan, D.; Buldgen, G.; Lovis, C.; Eggenberger, P.; Pezzotti, C.; Adibekyan, V. et al. (January 2022). "CORALIE radial-velocity search for companions around evolved stars (CASCADES): I. Sample definition and first results: Three new planets orbiting giant stars". Astronomy & Astrophysics 657: A87. doi:10.1051/0004-6361/202040078. ISSN 0004-6361. Bibcode2022A&A...657A..87O. 
  8. 8.0 8.1 De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (January 2014). "A catalog of rotational and radial velocities for evolved stars V: Southern stars *". Astronomy & Astrophysics 561: A126. doi:10.1051/0004-6361/201220762. ISSN 0004-6361. Bibcode2014A&A...561A.126D. 
  9. 9.0 9.1 Gomes da Silva, J.; Santos, N. C.; Adibekyan, V.; Sousa, S. G.; Campante, T. L.; Figueira, P.; Bossini, D.; Delgado-Mena, E. et al. (February 2021). "Stellar chromospheric activity of 1674 FGK stars from the AMBRE-HARPS sample. I. A catalogue of homogeneous chromospheric activity". Astronomy & Astrophysics 646: A77. doi:10.1051/0004-6361/202039765. ISSN 0004-6361. Bibcode2021A&A...646A..77G. 
  10. "* pi.02 Dor". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+pi.02+Dor. 
  11. Eggleton, P. P.; Tokovinin, A. A. (11 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. ISSN 0035-8711. Bibcode2008MNRAS.389..869E. 
  12. Gontcharov, George A.; Mosenkov, Aleksandr V. (28 September 2017). "Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars". Monthly Notices of the Royal Astronomical Society 472 (4): 3805–3820. doi:10.1093/mnras/stx2219. ISSN 0035-8711. Bibcode2017MNRAS.472.3805G. 
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