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Using CHIRON spectr...
Using CHIRON spectroscopy to test the hypothesis of a precessing orbit for the WN4 star EZ CMa
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- Barclay, Krister D. G. (author)
- Embry Riddle Aeronaut Univ, Phys & Astron, 3700 Willow Creek Rd, Prescott, AZ 86301 USA.;SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA.
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- Rosu, Sophie (author)
- KTH,Partikel- och astropartikelfysik
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- Richardson, Noel D. (author)
- Embry Riddle Aeronaut Univ, Phys & Astron, 3700 Willow Creek Rd, Prescott, AZ 86301 USA.
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- Chene, Andre-Nicolas (author)
- US ELTP NSFs NOIRLab, 670 N Aohoku Pl, Hilo, HI 96720 USA.
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- St-Louis, Nicole (author)
- Univ Montreal, Dept Phys, Complexe Sci, 1375 Ave Therese Lavoie Roux, Montreal, PQ H2V 0B3, Canada.
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- Ignace, Richard (author)
- East Tennessee State Univ, Dept Phys & Astron, Johnson City, TN 37614 USA.
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- Moffat, Anthony F. J. (author)
- Univ Montreal, Dept Phys, Complexe Sci, 1375 Ave Therese Lavoie Roux, Montreal, PQ H2V 0B3, Canada.
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Embry Riddle Aeronaut Univ, Phys & Astron, 3700 Willow Creek Rd, Prescott, AZ 86301 USA;SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. Partikel- och astropartikelfysik (creator_code:org_t)
- Oxford University Press (OUP), 2023
- 2023
- English.
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In: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 527:2, s. 2198-2208
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https://doi.org/10.1...
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https://urn.kb.se/re...
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Abstract
Subject headings
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- The bright WN4 star EZ CMa exhibits a 3.77 d periodicity in photometry , spectroscopy , and polarimetry , but the variations in the measurements are not strictly phase-locked, exhibiting changes in reference times, amplitudes, and the shape of the variability happening over times as short as a few weeks. Recently, 137 d of contiguous, variable photometry from BRITE-constellation was interpreted as caused either by large-scale dense wind structures modulated by rotation, or by a fast-precessing binary having a slightly shorter 3.626 d orbital period and a fast apsidal motion rate of 1315(degrees) yr( -1). We aim at testing the latter hypothesis through analysis of spectroscopy and focus on the N V lambda 4945 line. We derive an orbital solution for the system and reject the 3.626 d period to represent the variations in the radial velocities of EZ CMa. An orbital solution with an orbital period of 3.77 d was obtained but at the cost of an extremely high and thus improbable apsidal motion rate. Our best orbital solution yields a period of 3.751 +/- 0.001 d with no apsidal motion. We place our results in the context of other variability studies and system properties. While we cannot fully reject the precessing binary model, we find that the corotating interaction region (CIR) hypothesis is better supported by these and other data through qualitative models of CIRs.
Subject headings
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Keyword
- techniques: spectroscopic
- binaries: spectroscopic
- stars: early-type
- stars: individual: WR 6
- stars: rotation
- stars: Wolf-Rayet
Publication and Content Type
- ref (subject category)
- art (subject category)
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