WDS 17157-0949 TOK 53 Ba,Bb : NOTES
 
 
discov_num notes refcode
A 2592 AB: Malkov et al. (2012) derive dynamical, photometric, and
spectroscopic masses 20.39 +/- 12.95, 4.49, 1.13 Msun, respectively. Mlk2012
AB + TOK 53Ba,Bb: This is the triple system HIP 84430. We computed
the first orbit of the secondary subsystem Ba,Bb which was discovered
at SOAR in 2009 and has just completed one full revolution since. Its
separation is always close to the diffraction limit. Adopting a mass
sum of 2.6 Msun for Ba,Bb, the resulting dynamical parallax is
7.6+/-1.5mas, while the HIP2 parallax is 4.9+/-0.9mas. The latest
orbit of the outer pair A 2592 AB published in Tokovinin et al. (2014) [Tok2014
does not account for the fact that the speckle measurements at SOAR
refer to A,Ba and not to AB. Here we give a more accurate solution
that uses the positions of AB computed from the measures of A,Ba under
the assumption that Ba and Bb have equal masses. After this correction
and orbit adjustment, the weighted residuals are 4.3mas in separation
and 1.3deg in angle. Interestingly, there were a considerable number
of speckle-interferometry measures of this pair obtained in the 1980's
and 1990's at 4-m telescopes, but none of them recognized the
subsystem Ba,Bb, despite its small dm.
Ignoring the multiplicity, the spectroscopic survey of Guillout et al.
(2009 A&A 504, 829) determined a moderate axial rotation V sin i =
10.8km/s and detected the lithium line of 52.8mA equivalent width
which, together with the X-ray detection by ROSAT (RasTyc 1715-0948),
normally indicates youth. These authors do not mention this star in
particular, but discuss a group of active lithium-rich giants in their
sample, to which this system apparently belongs. Even with the larger
dynamical parallax (instead of the HIP2 parallax), all three resolved
components of HIP 84430 are located above the main sequence in the
color-magnitude diagram. This multiple system is peculiar and merits
further study. Tok2015c
 
 
REFERENCES
 
 
refcode metd author reference
Mlk2012 not - Malkov, O.Yu., Tamazian, V.S., Docobo, J.A., & Chulkov, D.A. 2012A&A...546A..69M
Mlk2012 A&A 546, A69, 2012
Tok2015c orb+j Tokovinin, A., Mason, B.D., Hartkopf, W.I., Mendez, R.A., & Horch, E.P. 2015AJ....150...50T
Tok2015c +St AJ 150, 50, 2015 (some measures corrected in Tok2017b) 2017AJ....154..110T
Tok2021b orb Tokovinin, A. 2021AJ....161..144T
Tok2021b AJ 161, 144, 2021
 
 
DISCOVERER
 
 
idgroup discov author
1 A Aitken, R.G.
 
 
WDS HISTORIC DATA
 
 
coord_2000 discov_num comp epoch obs pa sep mag_pri mag_sec spectr notes coord_arcsec_2000
17157-0949 TOK 53 Ba,Bb 2009 2 141 0.0 10.40 10.60 N 171541.08-094831.9
17157-0949 TOK 53 Ba,Bb 2012 3 216 0.0 10.40 10.60 N 171541.08-094831.9
17157-0949 TOK 53 Ba,Bb 2013 6 175 0.0 10.40 10.60 F9IV N 171541.08-094831.9
17157-0949 TOK 53 Ba,Bb 2014 8 147 0.0 10.40 10.60 F9IV NO 171541.08-094831.9
17157-0949 TOK 53 Ba,Bb 2017 9 229 0.0 10.40 10.60 F9IV NO 171541.08-094831.9
17157-0949 TOK 53 Ba,Bb 2018 14 173 0.0 10.40 10.60 F9IV NO 171541.08-094831.9
17157-0949 TOK 53 Ba,Bb 2019 17 152 0.0 10.40 10.60 F9IV NO 171541.08-094831.9
17157-0949 TOK 53 Ba,Bb 2020 18 0 0.0 10.40 10.60 F9IV NO 171541.08-094831.9
17157-0949 TOK 53 Ba,Bb 2021 21 279 0.0 10.40 10.60 F9IV NO 171541.08-094831.9

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