ADS 9731

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ADS 9731
Observation data
Epoch J2000        Equinox J2000
Constellation Corona Borealis [1]
Right ascension 15h 38m 12.91478s [2]
Declination +36° 14′ 48.5597″ [2]
Apparent magnitude  (V)6.9 (total) [3]
Characteristics
Spectral type F4V, F5V, G4V, F3V, F7V, M3V? [4]
Astrometry
A
Proper motion (μ)RA: +73.197 [5] mas/yr
Dec.: −57.740 [5] mas/yr
Parallax (π)9.0945±0.0175  mas [5]
Distance 358.6 ± 0.7  ly
(110.0 ± 0.2  pc)
Absolute magnitude  (MV)+2.462 [6]
B
Proper motion (μ)RA: +71.824 [7] mas/yr
Dec.: −54.140 [7] mas/yr
Parallax (π)9.1101±0.0307  mas [7]
Distance 358 ± 1  ly
(109.8 ± 0.4  pc)
Absolute magnitude  (MV)+4.94 [4]
C
Proper motion (μ)RA: +75.165 [8] mas/yr
Dec.: −59.731 [8] mas/yr
Parallax (π)9.0970±0.0199  mas [8]
Distance 358.5 ± 0.8  ly
(109.9 ± 0.2  pc)
Absolute magnitude  (MV)+2.72 [4]
D
Proper motion (μ)RA: +72.818 [9] mas/yr
Dec.: −58.281 [9] mas/yr
Parallax (π)9.0870±0.0322  mas [9]
Distance 359 ± 1  ly
(110.0 ± 0.4  pc)
Absolute magnitude  (MV)+3.82 [4]
Orbit [3]
PrimaryA
CompanionB
Period (P)834 yr
Semi-major axis (a)1.249″
Inclination (i)97.0°
Orbit [3]
PrimaryC
CompanionD
Period (P)1,230 yr
Semi-major axis (a)1.582″
Inclination (i)78.4°
Orbit [3]
PrimaryAa
CompanionAb
Period (P)3.2732 days
Eccentricity (e)0.011
Semi-amplitude (K1)
(primary)		85.67 km/s
Semi-amplitude (K2)
(secondary)		87.28 km/s
Orbit [3]
PrimaryDa
CompanionDb
Period (P)14.284 days
Eccentricity (e)0.31
Semi-amplitude (K1)
(primary)		9.92 km/s
Other designations
BD+36°2626, HD 139691, CCDM J15382+3615AB, WDS J15382+3615AB
Database references
SIMBAD data

ADS 9731 is a star system that consists of six stars, located in the constellation of Corona Borealis. Four of the stars are visually separate in the sky, forming a visual star system, which was resolved using adaptive optics in 1995. [10] Two of these stars were themselves found to be spectroscopic binaries in 1998, resulting in a total of six known stars in the system. [4] It is one of very few multiple star systems known to have at least six members. [4]

Aa
Period = 3.27 d
Ab
Period = 834 y
B
Period > 20,000 y
C
Period = 1,230 y
Da
Period = 14.28 d
Db

Hierarchy of orbits

The components are organised thus: Aa and Ab are yellow-white main sequence stars of spectral types F4V and F5V and 1.35 and 1.32 solar masses respectively, which orbit each other every 3.27 days. This pair is in a 834-year orbit with star B, a star of spectral type G4V that has about 66% of the mass of the Sun. Star C is a yellow white star of spectral type F3V around 1.41 times as massive as the sun, which has just started brightening and moving off the main sequence. It is in a 1,230-year orbit with a pair of stars, Da and Db, a yellow-white main sequence star of spectral type F7V and a red dwarf of spectral type M3V respectively. Da and Db take 14.28-days to orbit each other. Finally the system of stars C and Dab, and the system of stars Aab and B, take over 20,000 years to orbit each other. [3] [4]

The combined light from the whole system results in an integrated V magnitude of 6.9. [3] Published apparent magnitudes for the components vary greatly and some are certainly in error, [4] but components A, B, C, and D are approximately of visual magnitude 7.8, 10.2, 8.0, and 9.1 respectively. [3] Models of all six components show that Aa and Ab have magnitudes 8.5 and 8.7 respectively while the faint secondary to component D is about 16th magnitude. The CD pair is slightly brighter than the AB pair, although component A is slightly brighter than component C. [4]

Gaia EDR3 catalogues parallaxes for the four resolved stars, all at a distance of 360 light-years (110 pc) with a statistical margin of error of less than a parsec.

The star system has been considered as a possible target for direct imaging searches for exoplanets, [11] but no planets have yet been detected in the system.

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific . 99 (617): 695. Bibcode:1987PASP...99..695R. doi: 10.1086/132034 . Constellation record for this object at VizieR.
  2. 1 2 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.
  3. 1 2 3 4 5 6 7 8 Tokovinin, Andrei (2018). "The Updated Multiple Star Catalog". The Astrophysical Journal Supplement Series. 235 (1): 6. arXiv: 1712.04750 . Bibcode:2018ApJS..235....6T. doi: 10.3847/1538-4365/aaa1a5 .
  4. 1 2 3 4 5 6 7 8 9 Tokovinin, A. A.; Shatskii, N. I.; Magnitskii, A. K. (1998). "ADS 9731: A new sextuple system". Astronomy Letters . 24 (6): 795. Bibcode:1998AstL...24..795T.
  5. 1 2 3 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv: 2012.01533 . Bibcode:2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657 . S2CID   227254300. (Erratum:  doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  6. ↑ Freund, S.; Robrade, J.; Schneider, P. C.; Schmitt, J. H. M. M. (2018). "The stellar content of the XMM-Newton slew survey". Astronomy and Astrophysics. 614: A125. arXiv: 1712.07410 . Bibcode:2018A&A...614A.125F. doi:10.1051/0004-6361/201732009.
  7. 1 2 3 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv: 2012.01533 . Bibcode:2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657 . S2CID   227254300. (Erratum:  doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  8. 1 2 3 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv: 2012.01533 . Bibcode:2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657 . S2CID   227254300. (Erratum:  doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  9. 1 2 3 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv: 2012.01533 . Bibcode:2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657 . S2CID   227254300. (Erratum:  doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  10. ↑ Drummond, Jack D.; Christou, Julian C.; Fugate, Robert Q. (1995). "Full Adaptive Optics Images of ADS 9731 and MU Cassiopeiae: Orbits and Masses". Astrophysical Journal . 450: 380. Bibcode:1995ApJ...450..380D. doi:10.1086/176148.
  11. ↑ Janson, M. (2010). "The relevance of prior inclination determination for direct imaging of Earth-like planets". Monthly Notices of the Royal Astronomical Society . 408 (1): 514–521. arXiv: 1006.2941 . Bibcode:2010MNRAS.408..514J. doi: 10.1111/j.1365-2966.2010.17135.x . S2CID   118380508.
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