The understanding of fluctuations in systems far from equilibrium is one of the key issues of non-equilibrium statistical thermodynamics. The Fluctuation Theorem of Gallavotti and Cohen (1995) [GCFT] portrays some symmetry featur ... more

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We use machine learning to build a constrained multiple regression model for rapidly estimating the fundamental stellar parameters of main-sequence solar-like stars (Bellinger & Angelou 2016). We train a random forest of decision ... more

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In current approaches to time-distance helioseismology, the line-of-sight projection effect on the traveltimes is not fully taken into account. Furthermore, filtering of full-disc data induces leakage due to the projection onto ... more

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Spectropolarimetric measurements allow us to detect and measure magnetic field through Zeeman effect in stellar photospheres. We observed with the spectropolarimeters Narval (at Telescope Bernard Lyot) and ESPADONS (at CFHT) a few ... more

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In time-distance helioseismology wave travel times are measured from the cross-correlation between Doppler velocities recorded at any two locations on the solar surface. All local helioseismology inferences rely critically on the ... more

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We extend an existing Born approximation model for calculating the linear sensitivity of helioseismic travel-times to flows from Cartesian to spherical geometry. This development is necessary to use the Born approximation for in ... more

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Solar-like oscillations exhibit a regular pattern of frequencies. This pattern is dominated by the small and large frequency separations between modes. The accurate determination of these parameters is of great interest, because ... more

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Binary stars systems are crucial to better understand the physics of stars, because they might share a common history, enabling us to assume that they have the same age and composition. Furthermore, using the Kepler laws, the orbi ... more

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Stellar acoustic oscillations are affected by magnetic activity, however it is unclear how a single starspot would affect the power spectrum of oscillations. Since the starspot rotates with the star, it causes a perturbation that ... more

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We have initiated a large survey with K2, to observe thousands of RR Lyrae stars along the ecliptic. The high photometric precision and the 80-90-day continuous coverage will allow us to investigate the light variation of these ga ... more

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