2 Equulei

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2 Equulei
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Equuleus
A
Right ascension 21h 02m 12.50262s [1]
Declination +07° 10′ 47.1545″ [1]
Apparent magnitude  (V)7.41 [2]
B
Right ascension 21h 02m 12.39375s [3]
Declination +07° 10′ 44.7957″ [3]
Apparent magnitude  (V)7.64 [2]
Characteristics
A
Evolutionary stage subgiant [1]
Spectral type F6V [4]
B
Evolutionary stage subgiant [3]
Spectral type F3V [5]
Astrometry
Radial velocity (Rv)−4.8±1.6 [6] km/s
Absolute magnitude  (MV)2.16±0.18 [7]
A
Proper motion (μ)RA: −9.184 [1] mas/yr
Dec.: −12.915 [1] mas/yr
Parallax (π)8.8125±0.2481  mas [1]
Distance 370 ± 10  ly
(113 ± 3  pc)
B
Proper motion (μ)RA: −4.238 [3] mas/yr
Dec.: −17.934 [3] mas/yr
Parallax (π)8.5577 ± 0.0298  mas [3]
Distance 381 ± 1  ly
(116.9 ± 0.4  pc)
Details
2 Equ A
Mass 1.73 [6]   M☉
Radius 2.6 [1]   R☉
Luminosity 12.9 [1]   L☉
Surface gravity (log g)3.84 [1]   cgs
Temperature 6,127 [1]   K
Metallicity [Fe/H]0.17 [6]   dex
Age 1.9 [1]   Gyr
2 Equ B
Mass 1.61 [3]   M☉
Radius 2.8 [3]   R☉
Luminosity10.9 [3]   L☉
Surface gravity (log g)3.72 [3]   cgs
Temperature 6,420 [3]   K
Age 2.2 [3]   Gyr
Other designations
λ  Equ, 2  Equulei, BD+06°4731, HD  200256, HIP  103813, LTT  16227, SAO  126482 [8]
Database references
SIMBAD data

2 Equulei is a double star system in the constellation of Equuleus.

The primary component of the 2 Equulei pair is an F-type star. As of 2015, the secondary had an angular separation of 2.90  arc seconds along a position angle of 213° from the primary. [2] They form a common proper motion pair, two stars at approximately the same distance and moving in the same direction. [4] Gaia DR3 gives them parallaxes of 8.8125±0.2471  mas and 8.5577±0.0298 mas respectively, although they are flagged as potentially unreliable. [1] [3] These parallaxes correspond to a distance of around 380  ly , in contrast to the Hipparcos distance of 260±20 ly for the two stars as a pair. [9]

2 Equulei has been referred to in some sources as λ (Lambda) Equulei, although it was not given that designation by Bayer. [10]

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  2. 1 2 3 Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi: 10.1086/323920 , retrieved 2015-07-22
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  4. 1 2 Abt, Helmut A. (2008). "Visual Multiples. IX. MK Spectral Types". The Astrophysical Journal Supplement Series. 176 (1): 216–217. Bibcode:2008ApJS..176..216A. doi: 10.1086/525529 .
  5. ↑ Adams, Walter S.; Joy, Alfred H.; Humason, Milton L.; Brayton, Ada Margaret (1935). "The Spectroscopic Absolute Magnitudes and Parallaxes of 4179 Stars". The Astrophysical Journal. 81: 187. Bibcode:1935ApJ....81..187A. doi:10.1086/143628.
  6. 1 2 3 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. ↑ "2 Equ -- Double or multiple star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg , retrieved 2017-02-17.
  9. ↑ van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv: 0708.1752 , Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID   18759600.
  10. ↑ Wagman, M. (August 1987). "Flamsteed's Missing Stars". Journal for the History of Astronomy. 18 (3): 215. Bibcode:1987JHA....18..209W. doi:10.1177/002182868701800305. S2CID   118445625.
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