Dynamical detection of three triple stellar systems in open clusters

Abstract

We present a kinematic analysis of three triple stellar systems belonging to two open clusters: CPD-60°961 and HD66137 in NGC2516, and HD315031 in NGC6530. All three systems are hierarchical triples with a close binary bound to a third body in a wider orbit, whose presence is detected through velocity variations of the close binary barycentre. Orbital parameters are derived from radial velocity curves. Absolute parameters for all stars are estimated assuming cluster membership. Some dynamical and evolutionary aspects of these systems are discussed, particularly the possible influence of Kozai cycles. The two systems of NGC2516 have similar orbital configurations with inner periods of 11.23 d and 8.70 d and outer periods of 9.79 yr and 9.24 yr. We report also radial velocity measurements of the components of the visual binary CPD-60°944 in NGC2516. Including results from previous works, this cluster would harbor 5 hierarchical triples. The young system HD315031 has an inner binary with a period of 1.37 d and a very eccentric (e=0.85) outer orbit with a period of 483 d. Possible dynamical evolutionary scenarios are discussed. Long-term radial velocity monitoring is highlighted as strategy for the detection of subsystems with intermediate separations, which are hard to cover with normal spectroscopic studies or visual techniques.

arXiv comment9 pages, 5 figures. Accepted by Monthly Notices of the Royal Astronomical Society

References in corpus (21)

• Evolution of binary stars and the effect of tides on binary populations
• Grids of stellar models with rotation - I. Models from 0.8 to 120 Msun at solar metallicity (Z = 0.014)
• Stellar Multiplicity
• Stellar, brown dwarf and multiple star properties from a radiation hydrodynamical simulation of star cluster formation
• Tertiary companions to close spectroscopic binaries
• POLLUX : a database of synthetic stellar spectra
• Stellar mass and age determinations - I. Grids of stellar models from Z=0.006 to 0.04 and M=0.5 to 3.5 Msun
• Populations of rotating stars. - I. Models from 1.7 to 15 Msun at Z = 0.014, 0.006, and 0.002 with Ω/Ωcrit between 0 and 1
• The Star Formation Region NGC 6530: distance, ages and Initial Mass Function
• An Analytic Technique for Constraining the Dynamical Origins of Multiple Star Systems Containing Merger Products
• Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum
• The Dynamical Significance of Triple Star Systems in Star Clusters
• Inhomogeneous surface distribution of chemical elements in the eclipsing binary AR Aur: A new challenge for our understanding of HgMn stars
• Rotation and activity in the solar-metallicity open cluster NGC2516
• Multiplicity of late-type B stars with HgMn peculiarity
• Magnetic fields of HgMn stars
• The infrared Hourglass cluster in M8
• Discovery of secular variations in the atmospheric abundances of magnetic Ap stars
• Chemical spots in the absence of magnetic field in the binary HgMn star 66 Eridani
• HD 65949: Rosetta Stone or Red Herring
• HD 65949: The Highest Known Mercury Excess Of Any CP Star?

Cited by in corpus (5)

• Magnetic OB[A] Stars with TESS: probing their Evolutionary and Rotational properties (MOBSTER) - I. First-light observations of known magnetic B and A stars
• The Gaia-ESO Survey: Asymmetric expansion of the Lagoon Nebula cluster NGC 6530 from GES and Gaia DR2
• Spectroscopic study of the extremely young O-type triple system Herschel 36 A in the Hourglass Nebula. I. Orbital properties
• The evolutionary state of the chemically peculiar members of the open cluster NGC2516
• The outer orbit of the high-mass stellar triple system Herschel 36 determined with the VLTI