TY - JOUR A1 - Pablo, Herbert A1 - Richardson, Noel D. A1 - Moffat, Anthony F. J. A1 - Corcoran, Michael A1 - Shenar, Tomer A1 - Benvenuto, Omar A1 - Fuller, Jim A1 - Naze, Yael A1 - Hoffman, Jennifer L. A1 - Miroshnichenko, Anatoly A1 - Apellaniz, Jesus Maiz A1 - Evans, Nancy A1 - Eversberg, Thomas A1 - Gayley, Ken A1 - Gull, Ted A1 - Hamaguchi, Kenji A1 - Hamann, Wolf-Rainer A1 - Henrichs, Huib A1 - Hole, Tabetha A1 - Ignace, Richard A1 - Iping, Rosina A1 - Lauer, Jennifer A1 - Leutenegger, Maurice A1 - Lomax, Jamie A1 - Nichols, Joy A1 - Oskinova, Lida A1 - Owocki, Stan A1 - Pollock, Andy A1 - Russell, Christopher M. P. A1 - Waldron, Wayne A1 - Buil, Christian A1 - Garrel, Thierry A1 - Graham, Keith A1 - Heathcote, Bernard A1 - Lemoult, Thierry A1 - Li, Dong A1 - Mauclaire, Benjamin A1 - Potter, Mike A1 - Ribeiro, Jose A1 - Matthews, Jaymie A1 - Cameron, Chris A1 - Guenther, David A1 - Kuschnig, Rainer A1 - Rowe, Jason A1 - Rucinski, Slavek A1 - Sasselov, Dimitar A1 - Weiss, Werner T1 - A coordinated X-Ray and optical campaign of the nearest massive eclipsing binary, delta ORIONIS Aa. III. Analysis of optical photometric (most) and spectroscopic (ground based) variations JF - The astrophysical journal : an international review of spectroscopy and astronomical physics N2 - 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 delta 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. KW - binaries: close KW - binaries: eclipsing KW - stars: early-type KW - stars: individual (delta Ori A) KW - stars: mass-loss KW - stars: variables: general Y1 - 2015 U6 - https://doi.org/10.1088/0004-637X/809/2/134 SN - 0004-637X SN - 1538-4357 VL - 809 IS - 2 PB - IOP Publ. Ltd. CY - Bristol ER -