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Correlated X-Ray and Optical Variability in the O-type Supergiant ζ Puppis.

Authors :
Nichols, Joy S.
Nazé, Yaël
Huenemoerder, David P.
Moffat, Anthony F. J.
Miller, Nathan A.
Lauer, Jennifer
Ignace, Richard
Gayley, Ken
Ramiaramanantsoa, Tahina
Oskinova, Lidia
Hamann, Wolf-Rainer
Richardson, Noel D.
Waldron, Wayne L.
Dahmer, Matthew
Source :
Astrophysical Journal; 1/10/2021, Vol. 906 Issue 2, p1-14, 14p
Publication Year :
2021

Abstract

Analysis of the recent long exposure Chandra X-ray observation of the early-type O star ζ Pup shows clear variability with a period previously reported in optical photometric studies. These 813 ks of HETGS observations taken over a roughly one-year time span have two signals of periodic variability: (1) a high-significance period of 1.7820 ± 0.0008 day, and (2) a marginal detection of periodic behavior close to either 5 days or 6 days. A BRITE-Constellation nanosatellite optical photometric monitoring (using near-contemporaneous observations to the Chandra data) confirms a 1.78060 ± 0.00088 day period for this star. The optical period coincides with the new Chandra period within their error ranges, demonstrating a link between these two wave bands and providing a powerful lever for probing the photosphere-wind connection in this star. The phase lag of the X-ray maximum relative to the optical maximum is ∼ ϕ = 0.45, but consideration of secondary maxima in both data sets indicates possibly two "hot" spots on the star with an X-ray phase lag of ϕ = 0.1 each. The details of this periodic variation of the X-rays are probed by displaying a phased and trailed X-ray spectrum and by constructing phased light curves for wavelength bands within the HETGS spectral coverage (ranging down to bands encompassing groups of emission lines). We propose that the 1.78 day period is the stellar rotation period and explore how stellar bright spots and associated corotating interaction regions (CIRs) could explain the modulation of this star's optical and X-ray output and their phase difference. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
0004637X
Volume :
906
Issue :
2
Database :
Complementary Index
Journal :
Astrophysical Journal
Publication Type :
Academic Journal
Accession number :
148167326
Full Text :
https://doi.org/10.3847/1538-4357/abca3a