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. =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 I_C_. Objects: --------------------------------------------------------------- RA (ICRS) DE Designation(s) --------------------------------------------------------------- 10 37 00.01 -08 50 23.8 HD 91962 = HIP 51966 --------------------------------------------------------------- File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- 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]) -------------------------------------------------------------------------------- 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 -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 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 -------------------------------------------------------------------------------- Byte-by-byte Description of file: table[56].dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 8 F8.3 yr Year [1903/2016] Besselian year 10- 14 F5.1 deg PA [0/360] Position angle {theta} 16- 20 F5.3 arcsec Sep [0/2] Separation {rho} 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 -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Sylvain Guehenneux [CDS] 12-Jun-2015