J/AJ/149/195 Spectroscopy of the quadruple system HD 91962 (Tokovinin+, 2015)
The unusual quadruple system HD 91962 with a "Planetary" architecture.
Tokovinin A., Latham D.W., Mason B.D.
<Astron. J., 149, 195 (2015)>
=2015AJ....149..195T 2015AJ....149..195T
ADC_Keywords: Stars, double and multiple ; X-ray sources ; Radial velocities
Keywords: binaries: general
Abstract:
The young nearby solar-type star HD 91962 is a rare quadruple system
where three companions revolve around the main component with periods
of 170.3days, 8.85years, and 205years. The two outer orbits are nearly
co-planar, and all orbits have small eccentricities. We refine the
visual orbit of the outer pair and determine the combined
spectro-interferometric orbit of the middle 8.8year pair and the
spectroscopic orbit of the inner binary. The middle and inner orbits
are likely locked in a 1:19 resonance, and the ratio of the outer and
middle periods is ∼23. The masses of all components are estimated
(inside-out: 1.14, 0.32, 0.64, 0.64 solar mass). The dynamical
parallax is 27.4±0.6mas. We speculate that this multiple system
originated from collapse of an isolated core and that the companions
migrated in a dissipative disk. Other multiple systems with similar
features (co-planarity, small eccentricity, and period ratio around
20) are known.
Description:
The young nearby solar-type star HD 91962 is a rare quadruple system
where three companions.
The spectrum of HD 91962 was monitored for 23 years starting in 1991.
Eighty-four observations were obtained with the CfA Digital
Speedometers initially using the 1.5m Wyeth Reflector at the Oak Ridge
Observatory in the town of Harvard, MA, and subsequently with the 1.5m
Tillinghast Reflector at the Whipple Observatory on Mount Hopkins, AZ.
Starting in 2009 the new fiber-fed Tillinghast Reflector Echelle
Spectrograph (TRES) was used to obtain an additional 10 observations.
The spectral resolution was 44000 for all three spectrographs, but the
typical signal-to-noise ratio (S/N) per resolution element of 100 for
the TRES observations was a few times higher than for the CfA Digital
Speedometer observations. The radial velocities used in the orbit
calculation and common residuals to the orbits of Aa1,Aa2, and Aa,Ab
are presented in Table 4.
All resolved measurements from speckle interferometry of the middle
subsystem Aa,Ab (Table 5) except the first one (made by Metchev &
Hillenbrand 2009, cat. J/ApJS/181/62) come from the 4.1m Southern
Astrophysical Research (SOAR) telescope. The observations were made
with the 534/22nm interference filter close to the Stromgren y-band
and the 788/132nm filter approximating the Cousins system IC.
Objects:
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RA (ICRS) DE Designation(s)
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10 37 00.01 -08 50 23.8 HD 91962 = HIP 51966
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 26 94 Radial velocities and residuals of Aa1,Aa2
(P=170.304±0.013d)
table5.dat 39 13 Measurements and residuals of Aa,Ab, from speckle
(P=3230.8±9d[8.846yr])
table6.dat 39 48 Measurements and residuals of A,B, from speckle
(P=74875d[2056yr])
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See also:
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
J/AJ/147/123 : 2012/2013 speckle interferometry with SOAR (Tokovinin+, 2014)
J/AJ/147/87 : From binaries to multiples. II. (Tokovinin, 2014)
J/AJ/139/743 : Speckle interferometry in 2008-09 (Tokovinin+, 2010)
J/ApJS/181/62 : Survey of young solar analogs (Metchev+, 2009)
J/A+A/493/1099 : CaII HK emission in rapidly rotating stars (Schroeder+, 2009)
J/AJ/133/2524 : Spectra of young nearby stars (White+, 2007)
J/A+A/356/141 : BV photometry for components of HIP doubles (Fabricius+ 2000)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 d JD [48290/56828] Julian Date (JD-2400000)
11- 15 F5.2 km/s RV [8.3/35] Radial velocity
17- 20 F4.2 km/s e_RV [0.1/0.6] Uncertainty in RV
22- 26 F5.2 km/s O-C The (O-C) residual
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Byte-by-byte Description of file: table[56].dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 yr Year [1903/2016] Besselian year
10- 14 F5.1 deg PA [0/360] Position angle θ
16- 20 F5.3 arcsec Sep [0/2] Separation ρ
22- 26 F5.3 arcsec e_Sep Assumed error used for weighting
28- 32 F5.1 deg (O-C)PA The (O-C) residual in position angle
34- 39 F6.3 arcsec (O-C)Sep The (O-C) residual in separation
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History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 12-Jun-2015