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, Lidia M.
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  - 
TY  - JOUR
A1  - Kupfer, Thomas
A1  - Bauer, Evan B.
A1  - van Roestel, Jan
A1  - Bellm, Eric C.
A1  - Bildsten, Lars
A1  - Fuller, Jim
A1  - Prince, Thomas A.
A1  - Heber, Ulrich
A1  - Geier, Stephan
A1  - Green, Matthew J.
A1  - Kulkarni, Shrinivas R.
A1  - Bloemen, Steven
A1  - Laher, Russ R.
A1  - Rusholme, Ben
A1  - Schneider, David
T1  - Discovery of a Double-detonation Thermonuclear Supernova Progenitor
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters
N2  - We present the discovery of a new double-detonation progenitor system consisting of a hot subdwarf B (sdB) binary with a white dwarf companion with a P (orb) = 76.34179(2) minutes orbital period. Spectroscopic observations are consistent with an sdB star during helium core burning residing on the extreme horizontal branch. Chimera light curves are dominated by ellipsoidal deformation of the sdB star and a weak eclipse of the companion white dwarf. Combining spectroscopic and light curve fits, we find a low-mass sdB star, M (sdB) = 0.383 +/- 0.028 M (circle dot) with a massive white dwarf companion, M (WD) = 0.725 +/- 0.026 M (circle dot). From the eclipses we find a blackbody temperature for the white dwarf of 26,800 K resulting in a cooling age of approximate to 25 Myr whereas our MESA model predicts an sdB age of approximate to 170 Myr. We conclude that the sdB formed first through stable mass transfer followed by a common envelope which led to the formation of the white dwarf companion approximate to 25 Myr ago. Using the MESA stellar evolutionary code we find that the sdB star will start mass transfer in approximate to 6 Myr and in approximate to 60 Myr the white dwarf will reach a total mass of 0.92 M (circle dot) with a thick helium layer of 0.17 M (circle dot). This will lead to a detonation that will likely destroy the white dwarf in a peculiar thermonuclear supernova. PTF1 J2238+7430 is only the second confirmed candidate for a double-detonation thermonuclear supernova. Using both systems we estimate that at least approximate to 1% of white dwarf thermonuclear supernovae originate from sdB+WD binaries with thick helium layers, consistent with the small number of observed peculiar thermonuclear explosions.
Y1  - 2022
U6  - https://doi.org/10.3847/2041-8213/ac48f1
SN  - 2041-8205
SN  - 2041-8213
VL  - 925
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  -