Now showing items 1-11 of 11

    • Characterization of Cataclysmic Variables and White Dwarfs in the Kepler Field 

      Doyle, Trisha (2015-05)
      We present long baseline Kepler photometry and ground-based Hale 200" spectroscopy of five known white dwarfs, five newly identified white dwarfs, and a cataclysmic variable, V523 Lyr. Analysis of the photometric and ...
    • The Devil Star: Analyzing Data from the Massive Magnetic Star HD66665 

      Adams, Brooke
      The magnetic massive star named tau Sco (Fig. 1) was unique with its unusually complex magnetic field until two other stars were discovered with similar light spectra, HD63425 and HD66665 (aka the “Devil star”). Dr. Petit ...
    • Evidence of magnetic field decay in massive main-sequence stars 

      Fossati, Luca; Schneider, Fabian R N; Castro, Norberto; Langer, Norbert; Simón-Díaz, Sergio; Müller, André Luís; De Koter, Alex; Morel, Thierry; Petit, Véronique; Sana, Hugues (2016-08)
      A significant fraction of massive main-sequence stars show strong, large-scale magnetic fields. The origin of these fields, their lifetimes, and their role in shaping the characteristics and evolution of massive stars are ...
    • HD 164492C: A rapidly rotating, Hα-bright, magnetic early B star associated with a 12.5 d spectroscopic binary 

      Wade, Gregg A.; Shultz, Matthew E.; Sikora, J.; Bernier, M.E.; Rivinius, Th H.; Alécian, Evelyne; Petit, Véronique; Grunhut, Jason H.; The BinaMIcS Collaboration (2016-10-21)
      We employ high-resolution spectroscopy and spectropolarimetry to derive the physical properties and magnetic characteristics of the multiple systemHD164492C, located in the young open cluster M20. The spectrum reveals ...
    • Magnetic massive stars as progenitors of 'heavy' stellar-mass black holes 

      Petit, Véronique; Keszthelyi, Zsolt; MacInnis, R.; Cohen, David H.; Townsend, R.H.D.; Wade, Gregg A.; Thomas, S.L.; Owocki, Stanley P.; Puls, Joachim; Ud-Doula, Asif (2016-12-02)
      The groundbreaking detection of gravitational waves produced by the inspiralling and coalescence of the black hole (BH) binary GW150914 confirms the existence of 'heavy' stellar-mass BHs with masses > 25 M⊙. Initial ...
    • Modulated X-ray emission of the magnetic O8.5V-star Tr16-22 

      Nazé, Yaël; Wade, Gregg A.; Petit, Véronique (2014-09-25)
      Using an extensive X-ray dataset, we analyzed the X-ray emission of the massive O-star Tr16-22, which was recently found to be magnetic. Its bright X-ray emission is found to be modulated with a 54d period. This timescale ...
    • Possible pair-instability supernovae at solar metallicity from magnetic stellar progenitors 

      Georgy, Cyril; Meynet, Georges; Ekström, Sylvia; Wade, Gregg A.; Petit, Véronique; Keszthelyi, Zsolt; Hirschi, Raphael (2017-03-01)
      Near-solar metallicity (and low-redshift) pair-instability supernova (PISN) candidates challenge stellar evolution models. Indeed, at such a metallicity, even an initially very massive star generally loses so much mass by ...
    • The puzzling properties of the magnetic O star Tr16-22 

      Nazé, Yaël; Barbá, Rodolfo H.; Bagnulo, Stefano; Morrell, Nidia I.; Gamen, Roberto C.; Petit, Véronique; Neiner, Coralie (2016-12)
      Context. The detection of bright, hard, and variable X-ray emission in Tr16-22 prompted spectropolarimetric observations of this star, which in turn led to the discovery of a surface magnetic field. Aims. We want ...
    • Separating Near-Object Spectra From Chandra Grating Observations 

      Smith, Max
      A vast amount of knowledge about stars comes from observing their spectra in the x-ray wavelengths; however, when there are multiple stars in close proximity, such as in binary systems or clusters, reading these spectra ...
    • Whole Earth Telescope discovery of a strongly distorted quadrupole pulsation in the largest amplitude rapidly oscillating Ap star 

      Holdsworth, Daniel L.; Kurtz, Donald W.; Saio, Hideyuki; Provençal, Judith L.; Letarte, Bruno; Sefako, Ramotholo R.; Petit, Véronique; Smalley, Barry; Thomsen, H.; Fletcher, C. L. (2018-01-01)
      We present a new analysis of the rapidly oscillating Ap (roAp) star, 2MASS J19400781 - 4420093 (J1940; V = 13.1). The star was discovered using SuperWASP broad-band photometry to have a frequency of 176.39 d-1 (2041.55 ...
    • X-ray emission from magnetic massive stars 

      Nazé, Yaël; Petit, Véronique; Rinbrand, Melanie; Cohen, David H.; Owocki, Stanley P.; Ud-Doula, Asif; Wade, Gregg A. (2014-10-30)
      Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. To clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM-Newton ...