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Masses, luminosities, and orbital coplanarities of the µ Orionis quadruple-star system from phases differential astrometry

Muterspaugh, Matthew W. and Lane, Benjamin F. and Fekel, Francis C. and Konacki, Maciej and Burke, Bernard F. and Kulkarni, S. R. and Colavita, M. M. and Shao, M. and Wiktorowicz, Sloane J. (2008) Masses, luminosities, and orbital coplanarities of the µ Orionis quadruple-star system from phases differential astrometry. Astronomical Journal, 135 (3). pp. 766-776. ISSN 0004-6256. doi:10.1088/0004-6256/135/3/766.

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μ Orionis was identified by spectroscopic studies as a quadruple-star system. Seventeen high-precision differential astrometry measurements of μ Ori have been collected by the Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES). These show both the motion of the long-period binary orbit and short-period perturbations superimposed on that caused by each of the components in the long-period system being themselves binaries. The new measurements enable the orientations of the long-period binary and short-period subsystems to be determined. Recent theoretical work predicts the distribution of relative inclinations between inner and outer orbits of hierarchical systems to peak near 40 and 140 degrees. The degree of coplanarity of this complex system is determined, and the angle between the planes of the A–B and Aa–Ab orbits is found to be 136.7 ± 8.3 degrees, near the predicted distribution peak at 140 degrees; this result is discussed in the context of the handful of systems with established mutual inclinations. The system distance and masses for each component are obtained from a combined fit of the PHASES astrometry and archival radial velocity observations. The component masses have relative precisions of 5% (component Aa), 15% (Ab), and 1.4% (each of Ba and Bb). The median size of the minor axes of the uncertainty ellipses for the new measurements is 20 micro-arcseconds (μas). Updated orbits for δ Equulei, κ Pegasi, and V819 Herculis are also presented.

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Kulkarni, S. R.0000-0001-5390-8563
Wiktorowicz, Sloane J.0000-0003-4483-5037
Additional Information:© 2008. The American Astronomical Society. Received 2007 July 9; accepted 2007 October 10; published 2008 January 29. We thank Daniel Fabrycky for helpful correspondence about his recent theoretical work on KCTF. We thank Bill Hartkopf for providing weights for the new non-PHASES differential astrometry measurements. PHASES benefits from the efforts of the PTI collaboration members who have each contributed to the development of an extremely reliable observational instrument. Without this outstanding engineering effort to produce a solid foundation, advanced phase-referencing techniques would not have been possible. We thank PTI's night assistant Kevin Rykoski for his efforts to maintain PTI in excellent condition and operating PTI in phase-referencing mode every week. Part of the work described in this paper was performed at the Jet Propulsion Laboratory under contract with the National Aeronautics and Space Administration. Interferometer data were obtained at the Palomar Observatory with the NASA Palomar Testbed Interferometer, supported by NASA contracts to the Jet Propulsion Laboratory. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This research has made use of the Simbad database, operated at CDS, Strasbourg, France. MWM acknowledges support from the Townes Fellowship Program. PHASES is funded in part by the California Institute of Technology Astronomy Department, and by the National Aeronautics and Space Administration under grant no. NNG05GJ58G issued through the Terrestrial Planet Finder Foundation Science Program. This work was supported in part by the National Science Foundation through grants AST 0300096, AST 0507590, and AST 0505366. The work of F.C.F. has been supported in part by NASA grant NCC5-511 and NSF grant HRD-9706268. M.K. is supported by the Polish Ministry of Science and Higher Education through grants N203 005 32/0449 and 1P03D 021 29.
Group:UNSPECIFIED, Division of Geological and Planetary Sciences
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Caltech Astronomy DepartmentUNSPECIFIED
Terrestrial Planet Finder Foundation Science ProgramUNSPECIFIED
Ministry of Science and Higher Education (Poland)N203 005 32/0449
Ministry of Science and Higher Education (Poland)1P03D 021 29
Subject Keywords:astrometry; binaries : close; binaries : visual; stars : distances; stars : individual (δ Equ, κ Peg, μ Orionis, V819 Her); techniques: interferometric.
Issue or Number:3
Record Number:CaltechAUTHORS:MUTaj08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13752
Deposited By: Ruth Sustaita
Deposited On:26 Jun 2009 16:47
Last Modified:08 Nov 2021 22:40

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