Mathieu Vrard
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View article: APOKASC-3: The Third Joint Spectroscopic and Asteroseismic Catalog for Evolved Stars in the Kepler Fields
APOKASC-3: The Third Joint Spectroscopic and Asteroseismic Catalog for Evolved Stars in the Kepler Fields Open
In the third APOKASC catalog, we present data for the complete sample of 15,808 evolved stars with APOGEE spectroscopic parameters and Kepler asteroseismology. We used 10 independent asteroseismic analysis techniques and anchor our system …
View article: Testing the Breakdown of the Asteroseismic Scaling Relations in Luminous Red Giants
Testing the Breakdown of the Asteroseismic Scaling Relations in Luminous Red Giants Open
Nearly all cool, evolved stars are solar-like oscillators, and fundamental stellar properties can be inferred from these oscillations with asteroseismology. Scaling relations are commonly used to relate global asteroseismic properties—the …
View article: Testing the Breakdown of the Asteroseismic Scaling Relations in Luminous Red Giants
Testing the Breakdown of the Asteroseismic Scaling Relations in Luminous Red Giants Open
Nearly all cool, evolved stars are solar-like oscillators, and fundamental stellar properties can be inferred from these oscillations with asteroseismology. Scaling relations are commonly used to relate global asteroseismic properties, the…
View article: APOKASC-3: The Third Joint Spectroscopic and Asteroseismic catalog for Evolved Stars in the Kepler Fields
APOKASC-3: The Third Joint Spectroscopic and Asteroseismic catalog for Evolved Stars in the Kepler Fields Open
In the third APOKASC catalog, we present data for the complete sample of 15,808 evolved stars with APOGEE spectroscopic parameters and Kepler asteroseismology. We used ten independent asteroseismic analysis techniques and anchor our system…
View article: Nature versus nurture: distinguishing effects from stellar processing and chemical evolution on carbon and nitrogen in red giant stars
Nature versus nurture: distinguishing effects from stellar processing and chemical evolution on carbon and nitrogen in red giant stars Open
The surface [C/N] ratios of evolved giants are strongly affected by the first dredge-up (FDU) of nuclear-processed material from stellar cores. C and N also have distinct nucleosynthetic origins and serve as diagnostics of mixing and mass-…
View article: Nature vs. Nurture: Distinguishing Effects from Stellar Processing and Chemical Evolution on Carbon and Nitrogen in Red Giant Stars
Nature vs. Nurture: Distinguishing Effects from Stellar Processing and Chemical Evolution on Carbon and Nitrogen in Red Giant Stars Open
The surface [C/N] ratios of evolved giants are strongly affected by the first dredge-up (FDU) of nuclear-processed material from stellar cores. C and N also have distinct nucleosynthetic origins and serve as diagnostics of mixing and mass …
View article: A close-in giant planet escapes engulfment by its star
A close-in giant planet escapes engulfment by its star Open
When main-sequence stars expand into red giants, they are expected to engulf close-in planets. Until now, the absence of planets with short orbital periods around post-expansion, core-helium-burning red giants has been interpreted as evide…
View article: A close-in giant planet escapes engulfment by its star
A close-in giant planet escapes engulfment by its star Open
Data for Nature article 'A close-in giant planet escapes engulfment by its star'. Included in this repository are: TESS oscillation spectra of host star -- tess_oscillation_spectra.zip CHFT ESPaDOnS spectropolarimetry of host star and cont…
View article: A close-in giant planet escapes engulfment by its star
A close-in giant planet escapes engulfment by its star Open
Data for Nature article 'A close-in giant planet escapes engulfment by its star'. Included in this repository are: TESS oscillation spectra of host star -- tess_oscillation_spectra.zip CHFT ESPaDOnS spectropolarimetry of host star and cont…
View article: Red Horizontal Branch stars: an asteroseismic perspective
Red Horizontal Branch stars: an asteroseismic perspective Open
Robust age estimates of red giant stars are now possible thanks to the precise inference of their mass based on asteroseismic constraints. However, there are cases where such age estimates can be highly precise yet very inaccurate. An exam…
View article: A “Quick Look” at All-sky Galactic Archeology with TESS: 158,000 Oscillating Red Giants from the MIT Quick-look Pipeline
A “Quick Look” at All-sky Galactic Archeology with TESS: 158,000 Oscillating Red Giants from the MIT Quick-look Pipeline Open
We present the first near all-sky yield of oscillating red giants from the prime mission data of NASA’s Transiting Exoplanet Survey Satellite (TESS). We apply machine learning toward long-cadence TESS photometry from the first data release…
View article: A 'Quick Look' at All-Sky Galactic Archeology with TESS: 158,000\n Oscillating Red Giants from the MIT Quick-Look Pipeline
A 'Quick Look' at All-Sky Galactic Archeology with TESS: 158,000\n Oscillating Red Giants from the MIT Quick-Look Pipeline Open
We present the first near all-sky yield of oscillating red giants from the\nprime mission data of NASA's Transiting Exoplanet Survey Satellite (TESS). We\napply machine learning towards long-cadence TESS photometry from the first data\nrel…
View article: Tracking the Evolution of Lithium in Giants Using Asteroseismology: Super-Li-rich Stars Are Almost Exclusively Young Red-clump Stars
Tracking the Evolution of Lithium in Giants Using Asteroseismology: Super-Li-rich Stars Are Almost Exclusively Young Red-clump Stars Open
We report novel observational evidence on the evolutionary status of lithium-rich giant stars by combining asteroseismic and lithium abundance data. Comparing observations and models of the asteroseismic gravity-mode period spacing ΔΠ 1 , …
View article: On using dipolar modes to constrain the helium glitch in red giant stars
On using dipolar modes to constrain the helium glitch in red giant stars Open
The space-borne missions CoRoT and Kepler have revealed numerous mixed modes in red giant stars. These modes carry a wealth of information about red giant cores, but are of limited use when constraining rapid structural variations in their…
View article: Influence of structural discontinuities present in the core of red-giant stars on the observed mixed-mode pattern and characterization of their properties
Influence of structural discontinuities present in the core of red-giant stars on the observed mixed-mode pattern and characterization of their properties Open
The space-borne missions CoRoT and Kepler have provided seismic data of unprecedented quality. Among the observed stars, red giants show a complex oscillation pattern exhibiting pressure modes as well as mixed modes. The latter carry infor…
View article: Analytical modelling of period spacings across the HR diagram
Analytical modelling of period spacings across the HR diagram Open
The characterization of stellar cores may be accomplished through the modelling of asteroseismic data from stars exhibiting either gravity-mode or mixed-mode pulsations, potentially shedding light on the physical processes responsible for …
View article: Period spacings in red giants <i>(Corrigendum)</i>
Period spacings in red giants <i>(Corrigendum)</i> Open
International audience
View article: Kepler red-clump stars in the field and in open clusters: constraints on core mixing
Kepler red-clump stars in the field and in open clusters: constraints on core mixing Open
International audience
View article: Period spacings in red giants
Period spacings in red giants Open
Context. The power of asteroseismology relies on the capability of global oscillations to infer the stellar structure. For evolved stars, we benefit from unique information directly carried out by mixed modes that probe their radiative cor…
View article: Radial mode widths in red giant stars spectra observed by<i>Kepler</i>
Radial mode widths in red giant stars spectra observed by<i>Kepler</i> Open
The Kepler space mission has observed many solar-like pulsators, and helped to decipher their fundamental parameters (e.g: mass, radius, rotation). Most of the achievements recently obtained in that domain result from the analysis of the m…
View article: Period spacings in red giants; III. Coupling factors of mixed modes
Period spacings in red giants; III. Coupling factors of mixed modes Open
The power of asteroseismology relies on the capability of global oscillations to infer the stellar structure. For evolved stars, we benefit from unique information directly carried out by mixed modes that probe their radiative cores. This …
View article: Dipole modes with depressed amplitudes in red giants are mixed modes
Dipole modes with depressed amplitudes in red giants are mixed modes Open
Context. Seismic observations with the space-borne Kepler mission have shown that a number of evolved stars exhibit low-amplitude dipole modes, which is referred to as depressed modes. Recently, these low amplitudes have been attributed to…
View article: Period spacings in red giants II. Automated measurement
Period spacings in red giants II. Automated measurement Open
The space missions CoRoT and Kepler have provided photometric data of unprecedented quality for asteroseismology. A very rich oscillation pattern has been discovered for red giants, including mixed modes that are used to decipher the red g…
View article: Period spacings in red giants
Period spacings in red giants Open
International audience
View article: Testing the cores of first ascent red giant stars using the period spacing of g modes
Testing the cores of first ascent red giant stars using the period spacing of g modes Open
In the context of the determination of stellar properties using asteroseismology, we study the influence of rotation and convective-core overshooting on the properties of red giant stars. We used models in order to investigate the effects …