NOAO >   Observing Info >   Approved Programs >   2020B-0009

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Program Information for 2020B-0009


PI: Andrei Tokovinin, NOIRLab, atokovinin@ctio.noao.edu
Address: CTIO, Casilla 603, La Serena Chile

CoI: Brian D Mason, US Naval Observatory
CoI: Rachel A Matson, US Naval Observatory

Title: Orbits of compact triple systems and binaries

Abstract: Orbital architecture of hierarchical stellar systems provides insights on their formation -- an important and active research subject related to the formation of stars and planets. We have monitored a large sample of resolved triple systems by speckle interferometry at SOAR for a decade, collecting material for calculation of orbits to improve statistics of periods, eccentricities and relative inclinations. One of the early results of this program is the emergence of two families of hierarchies. Low-mass stars are often organized in planetary-like systems with moderate period ratios, small eccentricities, and quasi-coplanar orbits, suggesting formation and migration in a gas disk. In contrast, other multiples have misaligned orbits hinting at violent dynamical history. We ask observing time for continuation of this program. Our second goal is to obtain positional measurements of tight binaries with fast orbital motion. These data, combined with the {it Gaia} astrometry, will deliver accurate masses for a wide variety of stars. Our program includes binaries containing planets or disks, young PMS binaries, metal-poor stars, etc. It is constantly enriched by new discoveries.

Program Type: Long Term/Galactic

Scheduled Nights:
Run 1 (2020B):  SOAR/HRCam -- 1n on Oct 27 2020, Dec 03 2020
Run 1 (2021A):  SOAR/HRCam -- 1.5n on Feb 27 2021, Apr 26 2021, Jul 25 2021
Run 1 (2021B):  SOAR/HRCam -- 1.5n on Sep 23 2021, Nov 20 2021, Jan 15 2022


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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