| 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] |
| Distance | 129.9 ± 0.6
ly (39.8 ± 0.2 pc) |
| Absolute magnitude (MV) | 2.62 [7] |
| Details | |
| π2 Gru A | |
| Mass | 1.37 [8] M☉ |
| Radius | 1.93±0.07 [1] R☉ |
| Luminosity | 7.15±0.04 [1] L☉ |
| Surface gravity (log g) | 4.20 [8] cgs |
| Temperature | 6788+138 −101 [1] K |
| Metallicity [Fe/H] | −0.06 [6] dex |
| Age | 758 [8] Myr |
| Other designations | |
| 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]
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
-
^
"pi.02 Gru".
SIMBAD.
Centre de données astronomiques de Strasbourg. Retrieved 2017-06-25.
{{ cite web}}: CS1 maint: postscript ( link) - ^ 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.
- ^ Renson, P.; Manfroid, J. (2009), "Catalogue of Ap, HGMN and Am stars", Astronomy and Astrophysics, 498 (3): 961, Bibcode: 2009A&A...498..961R, doi: 10.1051/0004-6361/200810788.
- ^ 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.
| Stars |
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| Galaxies |
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| 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] |
| Distance | 129.9 ± 0.6
ly (39.8 ± 0.2 pc) |
| Absolute magnitude (MV) | 2.62 [7] |
| Details | |
| π2 Gru A | |
| Mass | 1.37 [8] M☉ |
| Radius | 1.93±0.07 [1] R☉ |
| Luminosity | 7.15±0.04 [1] L☉ |
| Surface gravity (log g) | 4.20 [8] cgs |
| Temperature | 6788+138 −101 [1] K |
| Metallicity [Fe/H] | −0.06 [6] dex |
| Age | 758 [8] Myr |
| Other designations | |
| 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]
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
-
^
"pi.02 Gru".
SIMBAD.
Centre de données astronomiques de Strasbourg. Retrieved 2017-06-25.
{{ cite web}}: CS1 maint: postscript ( link) - ^ 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.
- ^ Renson, P.; Manfroid, J. (2009), "Catalogue of Ap, HGMN and Am stars", Astronomy and Astrophysics, 498 (3): 961, Bibcode: 2009A&A...498..961R, doi: 10.1051/0004-6361/200810788.
- ^ 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.
| Stars |
| ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| |||||||||||
| Galaxies |
| ||||||||||
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