FIRST VISUAL ORBIT FOR THE PROTOTYPICAL COLLIDING-WIND BINARY WR 140

Journal Article · Sun Nov 20 00:00:00 EST 2011 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/742/1/L1· OSTI ID:22047364

Monnier, J D; Ming, Zhao; Pedretti, E; Baron, F; Kraus, S; Tannirkulam, A ^[1]; Millan-Gabet, R ^[2]; Berger, J -P ^[3]; Traub, W ^[4]; Schloerb, F P ^[5]; Ten Brummelaar, T; McAlister, H; Sturmann, L; Sturmann, J; Turner, N ^[6]; Ridgway, S ^[7]

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1. University of Michigan Astronomy Department, 941 Dennison Bldg, Ann Arbor, MI 48109-1090 (United States)
2. California Institute of Technology, NASA Exoplanet Science Institute, Pasadena, CA 91125 (United States)
3. IPAG, CNRs/UMR 5571, Universite J. Fourier, BP-53, F-38041 Grenoble Cedex (France)
4. Jet Propulsion Laboratory, California Institute of Technology, M/S 301-355, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)
5. Department of Astronomy, University of Massachusetts, Amherst, MA 01003-4610 (United States)
6. CHARA Array of Georgia State University, Mount Wilson, CA 91023 (United States)
7. National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)

Wolf-Rayet (WR) stars represent one of the final stages of massive stellar evolution. Relatively little is known about this short-lived phase and we currently lack reliable mass, distance, and binarity determinations for a representative sample. Here we report the first visual orbit for WR 140 (= HD193793), a WC7+O5 binary system known for its periodic dust production episodes triggered by intense colliding winds near periastron passage. The Infrared-Optical Telescope Array and Center for High Angular Resolution Astronomy interferometers resolved the pair of stars in each year from 2003 to 2009, covering most of the highly eccentric, 7.9 year orbit. Combining our results with the recently improved double-line spectroscopic orbit of Fahed et al., we find the WR 140 system is located at a distance of 1.67 {+-} 0.03 kpc, composed of a WR star with M{sub WR} = 14.9 {+-} 0.5 M{sub Sun} and an O star with M{sub O} = 35.9 {+-} 1.3 M{sub Sun }. Our precision orbit yields key parameters with uncertainties {approx}6 Multiplication-Sign smaller than previous work and paves the way for detailed modeling of the system. Our newly measured flux ratios at the near-infrared H and Ks bands allow a spectral energy distribution decomposition and analysis of the component evolutionary states.

• OSTI ID: 22047364
• Journal Information: Astrophysical Journal Letters, Vol. 742, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACCURACY
ASTRONOMY
ASTROPHYSICS
BINARY STARS
DISTANCE
ENERGY SPECTRA
INTERFEROMETERS
MASS
NEAR INFRARED RADIATION
ORBITS
RESOLUTION
STAR EVOLUTION
TELESCOPES