Time-series photometry of the O4 I(n)fp star zeta Puppis

Abstract

We report a time-series analysis of the O4 I(n)fp star zeta Pup, based on optical photometry obtained with the SMEI instrument on the Coriolis satellite, 2003--2006. A single astrophysical signal is found, with P = (1.780938 \pm 0.000093) d and a mean semi-amplitude of (6.9 \pm 0.3) mmag. There is no evidence for persistent coherent signals with semi-amplitudes in excess of ca. 2~mmag on any of the timescales previously reported in the literature. In particular, there is no evidence for a signature of the proposed rotation period, ca. 5.1~days; zeta Pup is therefore probably not an oblique magnetic rotator. The 1.8-day signal varies in amplitude by a factor ca. 2 on timescales of 10--100d (and probably by more on longer timescales), and exhibits modest excursions in phase, but there is no evidence for systematic changes in period over the 1000-d span of our observations. Rotational modulation and stellar-wind variability appear to be unlikely candidates for the underlying mechanism; we suggest that the physical origin of the signal may be pulsation associated with low-l oscillatory convection modes.

arXiv commentMNRAS, in press

References in corpus (13)

• Validation of the new Hipparcos reduction
• Grids of stellar models with rotation - I. Models from 0.8 to 120 Msun at solar metallicity (Z = 0.014)
• Dynamical Simulations of Magnetically Channeled Line-Driven Stellar Winds: I. Isothermal, Nonrotating, Radially Driven Flow
• The Galactic O-Star Spectroscopic Survey. I. Classification System and Bright Northern Stars in the Blue-Violet at R~2500
• Properties of Galactic early-type O-supergiants: A combined FUV-UV and optical analysis
• Variability in the CoRoT photometry of three hot O-type stars. HD 46223, HD 46150 and HD 46966
• On the origin of field O-type stars
• A detailed X-ray investigation of zeta Puppis - The variability on short and long timescales
• A mass-loss rate determination for zeta Puppis from the quantitative analysis of X-ray emission line profiles
• Radiation-driven winds of hot luminous stars. XVI. Expanding atmospheres of massive and very massive stars and the evolution of dense stellar clusters
• Linear analyses for the stability of radial and nonradial oscillations of massive stars
• Variations of the amplitudes of oscillation of the Be star Achernar
• The period and amplitude changes of Polaris (alpha UMi) from 2003 to 2007 measured with SMEI

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