From Wikipedia, the free encyclopedia
Pi2 Gruis
Observation data
Epoch J2000.0       Equinox J2000.0 ( ICRS)
Constellation Grus
Right ascension 22h 23m 07.98704s [1]
Declination −45° 55′ 42.5582″ [1]
Apparent magnitude (V) 5.622 [2] (5.71 + 11.3) [3]
Characteristics
Spectral type F3 III-IV [4] [3] or F0 V [5]
U−B color index +0.016 [2]
B−V color index +0.365 [2]
Astrometry
Radial velocity (Rv)3.0 [6] km/s
Proper motion (μ) RA: +233.166 [1]  mas/ yr
Dec.: −58.205 [1]  mas/ yr
Parallax (π)25.1061 ± 0.1256  mas [1]
Distance129.9 ± 0.6  ly
(39.8 ± 0.2  pc)
Absolute magnitude (MV)2.62 [7]
Details
π2 Gru A
Mass1.37 [8]  M
Radius1.93±0.07 [1]  R
Luminosity7.15±0.04 [1]  L
Surface gravity (log g)4.20 [8]  cgs
Temperature6788+138
−101
[1]  K
Metallicity [Fe/H]−0.06 [6]  dex
Age758 [8]  Myr
Other designations
π2 Gru, CD−46°14295, FK5 3786, HD 212132, HIP 110506, HR 8524, SAO 231111, WDS J22231-4556 [9]
Database references
SIMBAD data

π2 Gruis, Latinised as Pi2 Gruis, is a binary star [3] system in the southern constellation of Grus. It is faintly visible to the naked eye as a yellow-white hued star with an apparent visual magnitude of 5.622. [2] Based upon an annual parallax shift of 25.1  mas as seen from the Earth, [1] the system is located 130  light years from the Sun.

The primary, component A, is an F-type star of uncertain luminosity class. Malaroda (1975) gave it a stellar classification of F3 III-IV, [4] which would indicate an evolving subgiant/ giant star hybrid spectrum, whereas Houk (1978) listed it as class F0 V, [5] suggesting that it is an F-type main sequence star. It has been considered to be a chemically peculiar star, [10] but this is now considered doubtful. [11] It is 758 [8] million years old with 1.4 [8] times the mass of the Sun. The star is 1.9 [1] times the Sun's radius and is radiating 7 [1] times the luminosity of the Sun from its photosphere at an effective temperature of 6,788 K. [1]

The companion is a magnitude 11.3 star at an angular separation of 4.6  arc seconds. [3] Gaia Data Release 2 has measured a separate annual parallax for it of 25.3266±0.0871  mas, almost identical to the primary star, and indicates that it is a red dwarf. [12]

References

  1. ^ a b c d e f g h i j k l Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv: 1804.09365. Bibcode: 2018A&A...616A...1G. doi: 10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c d Cousins, A. W. J. (1983), "UBV photometry of E region standard stars of intermediate brightness", South African Astronomical Observatory Circular, 7 (7): 36–46, Bibcode: 1983SAAOC...7...36C.
  3. ^ a b c d 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, arXiv: 0806.2878, Bibcode: 2008MNRAS.389..869E, doi: 10.1111/j.1365-2966.2008.13596.x, S2CID  14878976.
  4. ^ a b Malaroda, S. (August 1975), "Study of the F-type stars. I. MK spectral types", Astronomical Journal, 80: 637–641, Bibcode: 1975AJ.....80..637M, doi: 10.1086/111786.
  5. ^ a b Houk, N. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Dept. of Astronomy, University of Michigan, Bibcode: 1978mcts.book.....H.
  6. ^ a b Casagrande, L.; et al. (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): 21, arXiv: 1103.4651, Bibcode: 2011A&A...530A.138C, doi: 10.1051/0004-6361/201016276, S2CID  56118016.
  7. ^ Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv: 0811.3982, Bibcode: 2009A&A...501..941H, doi: 10.1051/0004-6361/200811191, S2CID  118577511.
  8. ^ a b c d e David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv: 1501.03154, Bibcode: 2015ApJ...804..146D, doi: 10.1088/0004-637X/804/2/146, S2CID  33401607.
  9. ^ "pi.02 Gru". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-06-25.{{ cite web}}: CS1 maint: postscript ( link)
  10. ^ De Vaucouleurs, A. (1957), "Spectral types and luminosities of B, A and F southern stars", Monthly Notices of the Royal Astronomical Society, 117 (4): 449–462, Bibcode: 1957MNRAS.117..449D, doi: 10.1093/mnras/117.4.449.
  11. ^ Renson, P.; Manfroid, J. (2009), "Catalogue of Ap, HGMN and Am stars" (PDF), Astronomy and Astrophysics, 498 (3): 961, Bibcode: 2009A&A...498..961R, doi: 10.1051/0004-6361/200810788.
  12. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv: 1804.09365. Bibcode: 2018A&A...616A...1G. doi: 10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
From Wikipedia, the free encyclopedia
Pi2 Gruis
Observation data
Epoch J2000.0       Equinox J2000.0 ( ICRS)
Constellation Grus
Right ascension 22h 23m 07.98704s [1]
Declination −45° 55′ 42.5582″ [1]
Apparent magnitude (V) 5.622 [2] (5.71 + 11.3) [3]
Characteristics
Spectral type F3 III-IV [4] [3] or F0 V [5]
U−B color index +0.016 [2]
B−V color index +0.365 [2]
Astrometry
Radial velocity (Rv)3.0 [6] km/s
Proper motion (μ) RA: +233.166 [1]  mas/ yr
Dec.: −58.205 [1]  mas/ yr
Parallax (π)25.1061 ± 0.1256  mas [1]
Distance129.9 ± 0.6  ly
(39.8 ± 0.2  pc)
Absolute magnitude (MV)2.62 [7]
Details
π2 Gru A
Mass1.37 [8]  M
Radius1.93±0.07 [1]  R
Luminosity7.15±0.04 [1]  L
Surface gravity (log g)4.20 [8]  cgs
Temperature6788+138
−101
[1]  K
Metallicity [Fe/H]−0.06 [6]  dex
Age758 [8]  Myr
Other designations
π2 Gru, CD−46°14295, FK5 3786, HD 212132, HIP 110506, HR 8524, SAO 231111, WDS J22231-4556 [9]
Database references
SIMBAD data

π2 Gruis, Latinised as Pi2 Gruis, is a binary star [3] system in the southern constellation of Grus. It is faintly visible to the naked eye as a yellow-white hued star with an apparent visual magnitude of 5.622. [2] Based upon an annual parallax shift of 25.1  mas as seen from the Earth, [1] the system is located 130  light years from the Sun.

The primary, component A, is an F-type star of uncertain luminosity class. Malaroda (1975) gave it a stellar classification of F3 III-IV, [4] which would indicate an evolving subgiant/ giant star hybrid spectrum, whereas Houk (1978) listed it as class F0 V, [5] suggesting that it is an F-type main sequence star. It has been considered to be a chemically peculiar star, [10] but this is now considered doubtful. [11] It is 758 [8] million years old with 1.4 [8] times the mass of the Sun. The star is 1.9 [1] times the Sun's radius and is radiating 7 [1] times the luminosity of the Sun from its photosphere at an effective temperature of 6,788 K. [1]

The companion is a magnitude 11.3 star at an angular separation of 4.6  arc seconds. [3] Gaia Data Release 2 has measured a separate annual parallax for it of 25.3266±0.0871  mas, almost identical to the primary star, and indicates that it is a red dwarf. [12]

References

  1. ^ a b c d e f g h i j k l Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv: 1804.09365. Bibcode: 2018A&A...616A...1G. doi: 10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c d Cousins, A. W. J. (1983), "UBV photometry of E region standard stars of intermediate brightness", South African Astronomical Observatory Circular, 7 (7): 36–46, Bibcode: 1983SAAOC...7...36C.
  3. ^ a b c d 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, arXiv: 0806.2878, Bibcode: 2008MNRAS.389..869E, doi: 10.1111/j.1365-2966.2008.13596.x, S2CID  14878976.
  4. ^ a b Malaroda, S. (August 1975), "Study of the F-type stars. I. MK spectral types", Astronomical Journal, 80: 637–641, Bibcode: 1975AJ.....80..637M, doi: 10.1086/111786.
  5. ^ a b Houk, N. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Dept. of Astronomy, University of Michigan, Bibcode: 1978mcts.book.....H.
  6. ^ a b Casagrande, L.; et al. (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): 21, arXiv: 1103.4651, Bibcode: 2011A&A...530A.138C, doi: 10.1051/0004-6361/201016276, S2CID  56118016.
  7. ^ Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv: 0811.3982, Bibcode: 2009A&A...501..941H, doi: 10.1051/0004-6361/200811191, S2CID  118577511.
  8. ^ a b c d e David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv: 1501.03154, Bibcode: 2015ApJ...804..146D, doi: 10.1088/0004-637X/804/2/146, S2CID  33401607.
  9. ^ "pi.02 Gru". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-06-25.{{ cite web}}: CS1 maint: postscript ( link)
  10. ^ De Vaucouleurs, A. (1957), "Spectral types and luminosities of B, A and F southern stars", Monthly Notices of the Royal Astronomical Society, 117 (4): 449–462, Bibcode: 1957MNRAS.117..449D, doi: 10.1093/mnras/117.4.449.
  11. ^ Renson, P.; Manfroid, J. (2009), "Catalogue of Ap, HGMN and Am stars" (PDF), Astronomy and Astrophysics, 498 (3): 961, Bibcode: 2009A&A...498..961R, doi: 10.1051/0004-6361/200810788.
  12. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv: 1804.09365. Bibcode: 2018A&A...616A...1G. doi: 10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.

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