Publications (47)
The magnetic fields of intermediate-mass T Tauri stars : I. Magnetic detections and fundamental stellar parameters
Florent Villebrun, Evelyne Alecian, Gaitee Hussain +13
Context. The origin of the fossil magnetic fields detected in 5 to 10% of intermediate-mass main sequence stars is still highly debated. Aims. We want to bring observational constr…
Testing the Rossby Paradigm: Weakened Magnetic Braking in early K-type Stars
Travis S. Metcalfe, Pascal Petit, Jennifer L. van Saders +12
There is an intricate relationship between the organization of large-scale magnetic fields by a stellar dynamo and the rate of angular momentum loss due to magnetized stellar winds…
Magnetic field structure in single late-type giants: The weak G-band giant 37 Comae from 2008 to 2011
Svetla Tsvetkova, Pascal Petit, Renada Konstantinova-Antova +5
This work studies the magnetic activity of the late-type giant 37 Com. This star belongs to the group of weak G-band stars that present very strong carbon deficiency in their photo…
ATMOSPHERIX: III- Estimating the C/O ratio and molecular dynamics at the limbs of WASP-76 b with SPIRou
Thea Hood, Florian Debras, Claire Moutou +13
Measuring the abundances of C- and O-bearing species in exoplanet atmospheres enables us to constrain the C/O ratio, that contains indications about the planet formation history. W…
Static spectropolarimeter concept adapted to space conditions and wide spectrum constraints
Martin Pertenais, Coralie Neiner, Pernelle Bernardi +2
The issues related to moving elements in space and instruments working in broader wavelength ranges lead to a need for robust polarimeters, efficient on a wide spectral domain, and…
Measuring the magnetic fields in the chromospheres of low-mass stars
Tianqi Cang, Pascal Petit, Jean-François Donati +11
Magnetic fields in the upper atmospheres of solar-like stars are believed to provide an enormous amount of energy to power the hot coronae and drive large-scale eruptions that coul…
Mitigating stellar activity jitter with different line lists for least-squares deconvolution: analysis of a parametric and a randomised line selection
Stefano Bellotti, Pascal Petit, Julien Morin +5
Stellar activity limits the radial velocity search and characterisation of exoplanets, as it introduces spurious jitter in the data sets and prevents the correct retrieval of a pla…
Innovative static spectropolarimeter concept for wide spectral ranges: tolerancing study
Martin Pertenais, Coralie Neiner, Laurent Parès +1
Developing an efficient and robust polarimeter for wide spectral ranges and space applications is a main issue in many projects. As part of the UVMag consortium created to develop…
Preliminary design of the full-Stokes UV and visible spectropolarimeter for UVMag/Arago
Martin Pertenais, Coralie Neiner, Laurent Pares +3
The UVMag consortium proposed the space mission project Arago to ESA at its M4 call. It is dedicated to the study of the dynamic 3D environment of stars and planets. This space mis…
The obliquity of HIP 67522 b: a 17 Myr old transiting hot Jupiter-sized planet
Alexis Heitzmann, George Zhou, Samuel N. Quinn +7
HIP 67522 b is a 17 Myr old, close-in ( d), Jupiter-sized () transiting planet orbiting a Sun like star in the Sco-Cen OB association. We presen…
Magnetic geometry and surface differential rotation of the bright Am star Alhena A
Aurore Blazère, Pascal Petit, Coralie Neiner +5
Alhena A ( Gem A) is a bright Am star, with the strongest disc-integrated magnetic field strength reported so far for an Am star. Its spectrum exhibits standard circularly pola…
The impact of unresolved magnetic spots on high precision radial velocity measurements
Maksym Lisogorskyi, Sudeshna Boro Saikia, Sandra V. Jeffers +6
The Doppler method of exoplanet detection has been extremely successful, but suffers from contaminating noise from stellar activity. In this work a model of a rotating star with a…
Stellar Physics with High-Resolution UV Spectropolarimetry
Julien Morin, Jean-Claude Bouret, Coralie Neiner +26
Current burning issues in stellar physics, for both hot and cool stars, concern their magnetism. In hot stars, stable magnetic fields of fossil origin impact their stellar structur…
Science cases for a visible interferometer
Philippe Stee, France Allard, Myriam Benisty +54
High spatial resolution is the key for the understanding various astrophysical phenomena. But even with the future E-ELT, single dish instruments are limited to a spatial resolutio…
Magnetic fields on young, moderately rotating Sun-like stars II. EK Draconis (HD 129333)
Ian Waite, Stephen Marsden, Brad Carter +6
The magnetic fields, activity and dynamos of young solar-type stars can be empirically studied using time-series of spectropolarimetric observations and tomographic imaging techniq…
Ultra weak magnetic fields in Am stars: Beta UMa and theta Leo
Aurore Blazère, Pascal Petit, François Lignières +3
An extremely weak circularly-polarized signature was recently discovered in spectral lines of the chemically peculiar Am star Sirius A (Petit et al. 2011). This signal was interpre…
UVMag: Space UV and visible spectropolarimetry
Martin Pertenais, Coralie Neiner, Laurent Pares +3
UVMag is a project of a space mission equipped with a high-resolution spectropolarimeter working in the UV and visible range. This M-size mission will be proposed to ESA at its M4…
Chromaticity of stellar activity in radial velocities : Anti-correlated families of lines on the M dwarf EV Lac with SPIRou and SOPHIE
Pierre Larue, Xavier Delfosse, Andres Carmona +33
Context. In the search for exoplanets using radial velocities (RV), stellar activity has become one of the main limiting factors for detectability. Fortunately, activity-induced RV…
The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase
Didier Barret, Vincent Albouys, Jan-Willem den Herder +296
The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer, studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory, a versatile ob…
Multiwavelength Campaign Observations of a Young Solar-type Star, EK Draconis. III. Comparison between Starspot Mapping, Zeeman Doppler Imaging, and Multiwavelength Variability
Kai Ikuta, Kosuke Namekata, Pascal Petit +12
Recent simultaneous multiwavelength observations of a nearby young solar-type star EK Dra in the optical, H spectrum, and X-ray, have provided evidence for stellar prominence e…
Magnetic fields on young, moderately rotating Sun-like stars - I: HD~35296 and HD~29615
Ian Waite, Stephen Marsden, Bradley Carter +4
Observations of the magnetic fields of young solar-type stars provide a way to investigate the signatures of their magnetic activity and dynamos. Spectropolarimetry enables the stu…
Do non-dipolar magnetic fields contribute to spin-down torques?
Victor See, Sean P. Matt, Adam J. Finley +14
Main sequence low-mass stars are known to spin-down as a consequence of their magnetised stellar winds. However, estimating the precise rate of this spin-down is an open problem. T…
The effects of stellar winds on the magnetospheres and potential habitability of exoplanets
Victor See, Moira Jardine, Aline A. Vidotto +4
Context: The principle definition of habitability for exoplanets is whether they can sustain liquid water on their surfaces, i.e. that they orbit within the habitable zone. However…
Coronal mass ejections and type II radio emission variability during a magnetic cycle on the solar-type star Eridani
Dúalta à Fionnagáin, Robert D. Kavanagh, Aline A. Vidotto +5
We simulate possible stellar coronal mass ejection (CME) scenarios over the magnetic cycle of Eridani (18 Eridani; HD 22049). We use three separate epochs from 2008, 2011, and…
Anti-Solar Differential Rotation May Have Revived Magnetic Braking in the Subgiant 31 Aquilae
Travis S. Metcalfe, Jennifer L. van Saders, Thomas R. Ayres +16
Recent observations have shown that sufficiently slow rotation disrupts the organization of large-scale magnetic field in older main-sequence stars, leading to weakened magnetic br…
Multiwavelength Campaign Observations of a Young Solar-type Star, EK Draconis. I. Discovery of Prominence Eruptions Associated with Superflares
Kosuke Namekata, Vladimir S. Airapetian, Pascal Petit +14
Young solar-type stars frequently produce superflares, serving as a unique window into the young Sun-Earth environments. Large solar flares are closely linked to coronal mass eject…
Asteroseismology and Spectropolarimetry of the Exoplanet Host Star Serpentis
Travis S. Metcalfe, Derek Buzasi, Daniel Huber +31
The bright star Ser hosts a hot Neptune with a minimum mass of 13.6 and a 15.5 day orbit. It also appears to be a solar analog, with a mean rotation period of 25.8…
From solar to stellar corona: the role of wind, rotation and magnetism
Victor Réville, Allan Sacha Brun, Antoine Strugarek +4
Observations of surface magnetic fields are now within reach for many stellar types thanks to the development of Zeeman-Doppler Imaging. These observations are extremely useful for…
The Colorado Ultraviolet Transit Experiment (CUTE): A dedicated cubesat mission to study exoplanetary mass loss and magnetic fields
Brian T. Fleming, Kevin France, Nicholas Nell +10
The Colorado Ultraviolet Transit Experiment (CUTE) is a near-UV (2550 - 3300 Angstrom) 6U cubesat mission designed to monitor transiting hot Jupiters to quantify their atmospheric…
Discovery of a very weak magnetic field on the Am star Alhena
Aurore Blazère, Coralie Neiner, Pascal Petit
Alhena ( Gem) was observed in the frame of the BRITE (BRIght Target Explorer) spectropolarimetric survey, which gathers high resolution, high signal-to-noise, high sensitivity,…
The Colorado Ultraviolet Transit Experiment (CUTE) Mission Overview
Kevin France, Brian Fleming, Arika Egan +18
Atmospheric escape is a fundamental process that affects the structure, composition, and evolution of many planets. The signatures of escape are detectable on close-in, gaseous exo…
Inactive longitude and superflare in the active single-lined pre-main sequence binary V2279 Cyg
Xueying Hu, Tianqi Cang, Jian-Ning Fu +7
Young, solar-like stars in the pre-main sequence (PMS) stage exhibit vigorous magnetic activity that significantly influences their circumstellar environments and the processes of…
Pollux: a stable weak dipolar magnetic field but no planet ?
Michel Auriere, Renada Konstantinova-Antova, Olivier Espagnet +5
Pollux is considered as an archetype of a giant star hosting a planet: its radial velocity (RV) presents sinusoidal variations with a period of about 590 d, which have been stable…
A Bcool spectropolarimetric survey of over 150 solar-type stars
Stephen Marsden, Pascal Petit, Sandra Jeffers +3
As part of the Bcool project, over 150 solar-type stars chosen mainly from planet search databases have been observed between 2006 and 2013 using the NARVAL and ESPaDOnS spectropol…
Constraints on Magnetic Braking from the G8 Dwarf Stars 61 UMa and Cet
Travis S. Metcalfe, Klaus G. Strassmeier, Ilya V. Ilyin +11
During the first half of their main-sequence lifetimes, stars rapidly lose angular momentum to their magnetized winds, a process known as magnetic braking. Recent observations sugg…
The Rotationally Modulated Polarization of Boo A
Daniel V. Cotton, Dag Evensberget, Stephen C. Marsden +9
We have observed the active star Boo A (HD 131156A) with high precision broadband linear polarimetry contemporaneously with circular spectropolarimetry. We find both signals a…
The magnetic and spin-down properties of slowly rotating fully convective M dwarfs
Victor See, Louis Amard, Stefano Bellotti +19
The evolution of the magnetism, winds and rotation of low-mass stars are all linked. One of the most common ways to probe the magnetic properties of low-mass stars is with the Zeem…
CUTE reveals escaping metals in the upper atmosphere of the ultra-hot Jupiter WASP-189b
A. G. Sreejith, Kevin France, Luca Fossati +12
Ultraviolet observations of Ultra-hot Jupiters (UHJs), exoplanets with temperatures over 2000\,K, provide us with an opportunity to investigate if and how atmospheric escape shapes…
TOI-4562 b: A highly eccentric temperate Jupiter analog orbiting a young field star
Alexis Heitzmann, George Zhou, Samuel N. Quinn +47
We report the discovery of TOI-4562 b (TIC-349576261), a Jovian planet orbiting a young F7V-type star, younger than the Praesepe/Hyades clusters (< Myr). This planet stands o…
Multiwavelength Campaign Observations of a Young Solar-type Star, EK Draconis. II. Understanding Prominence Eruption through Data-Driven Modeling and Observed Magnetic Environment
Kosuke Namekata, Kai Ikuta, Pascal Petit +15
EK Draconis, a nearby young solar-type star (G1.5V, 50-120 Myr), is known as one of the best proxies for inferring the environmental conditions of the young Sun. The star frequentl…
The PLATO Mission
Heike Rauer, Conny Aerts, Juan Cabrera +842
PLATO (PLAnetary Transits and Oscillations of stars) is ESA's M3 mission designed to detect and characterise extrasolar planets and perform asteroseismic monitoring of a large numb…
Estimating magnetic filling factors from Zeeman-Doppler magnetograms
Victor See, Sean P. Matt, Colin P. Folsom +15
Low-mass stars are known to have magnetic fields that are believed to be of dynamo origin. Two complementary techniques are principally used to characterise them. Zeeman-Doppler im…
A spectro-polarimetric study of the planet-hosting G dwarf, HD 147513
Gaitee A. J. Hussain, Julian David Alvarado-Gómez, Jason Grunhut +12
The results from a spectro-polarimetric study of the planet-hosting Sun-like star, HD 147513 (G5V), are presented here. Robust detections of Zeeman signatures at all observed epoch…
A Long-Term Spectral Study of the Single Active Giant OP Andromedae
Stefan Georgiev, Renada Konstantinova-Antova, Ana Borisova +10
We present a spectral study of the single magnetically active K giant OP And in the period 1979 -- 2018, monitoring the variability of the activity indicator line H. Original d…
Colorado Ultraviolet Transit Experiment Near-Ultraviolet Transmission Spectroscopy of the Ultra-hot Jupiter KELT-9b
Arika Egan, Kevin France, Aickara Gopinathan Sreejith +9
We present new near-ultraviolet (NUV, = 2479 3306 ) transmission spectroscopy of KELT-9b, the hottest known exoplanet, obtained with the Colorado Ultraviolet Transit E…
Dynamo-generated magnetic fields in fast rotating single giants
Renada Konstantinova-Antova, Michel Aurière, Klaus-Peter Schröder +1
Red giants offer a good opportunity to study the interplay of magnetic fields and stellar evolution. Using the spectro-polarimeter NARVAL of the Telescope Bernard Lyot (TBL), Pic d…
The Origin of Weakened Magnetic Braking in Old Solar Analogs
Travis S. Metcalfe, Adam J. Finley, Oleg Kochukhov +10
The rotation rates of main-sequence stars slow over time as they gradually lose angular momentum to their magnetized stellar winds. The rate of angular momentum loss depends on the…