Presentation on theme: "Tracing the wind structures in WR113 Alexandre David-Uraz (supervisor : Tony Moffat) Université de Montréal."— Presentation transcript:
Tracing the wind structures in WR113 Alexandre David-Uraz (supervisor : Tony Moffat) Université de Montréal
Outline Brief theoretical context Introduction to CV Ser Spectroscopy and orbit Lamontagne et al. fit MOST photometry Clumping and wind collision What’s next?
Brief theoretical context WR stars have a very high mass loss rate, typically M ~ M /year This rate cannot be explained by the star’s luminosity alone A better understanding of the clumping phenomenon is crucial in solving this problem
Introduction to CV Ser WR113 = CV Ser = HD168206, SB2 RA 18:19:07.36, DEC -11:37:59.2 (J2000) Galactic coordinates: l = 18.91º b = +1.75º Spectral types: WC8d + O8-9 IV v = 9.43, b-v = P = ± d, e = 0 (?) Goal: use MOST to probe structures in the WR wind as its companion shines through it at different orbital positions
CV Ser – Field (DSS) 30'' x 30''
CV Ser – Optical spectroscopy (OMM) CIII 5696 CIV 5806 HeI 5876 CIII 4650 HeII 4686
CV Ser – Orbit (Massey & Niemela, 1981)
CV Ser – Radial velocity plot (DAO)
CV Ser – Radial velocity plot (DAO + OMM)
Orbit of the O star?
“Shift and add” method With the right orbit, it should be possible to separate each component’s individual spectrum with reasonable precision
Previous g-b photometry leading to i, dM/dt & M WR, M O (Lamontagne et al. 1996)
CV Ser light curve (Lamontagne et al., 1996)
Hjellming & Hiltner (1963)
CV Ser light curve (MOST)
Other light curves from the same field
Instrumental effects – HD Drift : (1.17±0.09)*10 -4 mag/d
Instrumental effects – MY Ser Drift : (5.4±0.1)*10 -4 mag/d
Lamontagne et al. fit applied to the MOST light curve
Lamontagne et al. fit “applied” to the other eclipse...
Random variations due to clumping?
Spectroscopic signs of clumping
How do the clumps affect the light curve? (an artist’s vision) WRWR Vers l’observateur O O O Phase ~ 0.5 Phase ~ 0.25 Phase ~ 0
Wind collision (Bartzakos et al. 2001) Lührs model
Excess emission (CIII 5696) in a WC4 + O9 binary
Excess emission in CV Ser (CIII 5696)
What’s next? Fourier analysis Fourier analysis in order to find pulsations in the star or its wind Wavelet analysisrandom variations Wavelet analysis in order to find random variations due to the clumping spectroscopic changes Linking these variations to spectroscopic changes the phase dependancy Establishing the phase dependancy of these variations Putting together a model of the clumping phenomenon Putting together a model of the clumping phenomenon new observation campaign A new observation campaign is scheduled for June/July 2010, both on the MOST space telescope and the spectrometer at OMM