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A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, δ Orionis Aa. III. Analysis of Optical Photometric (MOST) and Spectroscopic (Ground-based) Variations

Pablo, Herbert and Fuller, Jim (2015) A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, δ Orionis Aa. III. Analysis of Optical Photometric (MOST) and Spectroscopic (Ground-based) Variations. Astrophysical Journal, 809 (2). Art. No. 134. ISSN 0004-637X. doi:10.1088/0004-637X/809/2/134.

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We report on both high-precision photometry from the Microvariability and Oscillations of Stars (MOST) space telescope and ground-based spectroscopy of the triple system δ Ori A, consisting of a binary O9.5II+early-B (Aa1 and Aa2) with P = 5.7 days, and a more distant tertiary (O9 IV P > 400 years). This data was collected in concert with X-ray spectroscopy from the Chandra X-ray Observatory. Thanks to continuous coverage for three weeks, the MOST light curve reveals clear eclipses between Aa1 and Aa2 for the first time in non-phased data. From the spectroscopy, we have a well-constrained radial velocity (RV) curve of Aa1. While we are unable to recover RV variations of the secondary star, we are able to constrain several fundamental parameters of this system and determine an approximate mass of the primary using apsidal motion. We also detected second order modulations at 12 separate frequencies with spacings indicative of tidally influenced oscillations. These spacings have never been seen in a massive binary, making this system one of only a handful of such binaries that show evidence for tidally induced pulsations.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle
Pablo, Herbert0000-0002-1355-5860
Fuller, Jim0000-0002-4544-0750
Additional Information:© 2015 The American Astronomical Society. Received 2015 January 23; accepted 2015 March 25; published 2015 August 18. M.F.C., J.S.N., W.L.W., and K.H. are grateful for support via Chandra grant GO3-14015A and GO3-14015E. Y.N. acknowledges support from the Fonds National de la Recherche Scientifique (Belgium), the Communauté Française de Belgique, the PRODEX XMM and Integral contracts, and the Action de Recherche Concertée’ (CFWB-Académie Wallonie Europe). N.D.R. gratefully acknowledges his CRAQ (Centre de Recherche en Astrophysique du Québec) fellowship. A.F.J.M., D.B.G., J.M.M., and S.M.R. are grateful for financial aid to NSERC (Canada). A.F.J.M. and H.P. also thank FRQNT (Quebec) and the Canadian Space Agency. J.M. A. acknowledges support from (a) the Spanish Government Ministerio de Economía y Competitividad (MINECO) through grants AYA2010-15 081, AYA2010-17 631, and AYA2013- 40 611-P and (b) the Consejería de Educación of the Junta de Andalucía through grant P08-TIC-4075. R.K. and W.W. acknowledge support by the Austrian Science Fund (FWF). N.R.E. is grateful for support from the Chandra X-ray Center NASA Contract NAS8-03060. J.L.H. acknowledges support from NASA award NNX13AF40G and NSF award AST-0807477.
Group:TAPIR, Walter Burke Institute for Theoretical Physics
Funding AgencyGrant Number
Fonds de la Recherche Scientifique (FNRS)UNSPECIFIED
Communauté française de Belgique – Action de recherche concertée – Académie Wallonie-EuropeUNSPECIFIED
Centre de Recherche en Astrophysique du Québec (CRAQ)UNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Fonds de recherche du Québec – Nature et technologies (FRQNT)UNSPECIFIED
Canadian Space Agency (CSA)UNSPECIFIED
Ministerio de Economía y Competitividad (MINECO)AYA2010-15 081
Ministerio de Economía y Competitividad (MINECO)AYA2010-17 631
Ministerio de Economía y Competitividad (MINECO)AYA2013-40 611-P
Junta de AndalucíaP08-TIC-4075
FWF Der WissenschaftsfondsUNSPECIFIED
Subject Keywords:binaries: close – binaries: eclipsing – stars: early-type – stars: individual (delta Ori A) – stars: mass-loss – stars: variables: general
Issue or Number:2
Record Number:CaltechAUTHORS:20151019-105023448
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:61255
Deposited By: Tony Diaz
Deposited On:19 Oct 2015 18:01
Last Modified:10 Nov 2021 22:46

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