Related papers: Spin-orbit alignment and magnetic activity in the …
Early observations of T Tauri stars suggested that stars with evidence of circumstellar accretion disks rotated slower than stars without such evidence, but more recent results are not as clear. Near-IR circumstellar disk indicators, though…
Magnetic fields play a crucial role throughout stellar evolution, regulating angular momentum, channelling accretion, and launching jets and outflows. While the magnetic properties of Classical T Tauri Stars (CTTS) are well characterised,…
Equal-mass stars in young open clusters and loose associations exhibit a wide spread of rotation periods, which likely originates from differences in the initial rotation periods and in the primordial disc lifetimes. We want to explore if…
We aim to evaluate how well the variation of small-scale magnetic fields on the stellar surface can be monitored with time-series observations. Further, we aim to establish to what extent the measured total unsigned magnetic field traces…
Context. The rotation period of stars is an important parameter along with mass, radius, effective temperature. It is an essential parameter for any radial velocity monitoring, as stellar activity can mimic the presence of a planet at the…
Context: Recent spectropolarimetric observations of Herbig Ae/Be stars have yielded new arguments in favour of a fossil origin for the magnetic fields of intermediate mass stars. Aims: To study the evolution of these magnetic fields, and…
We present projected rotational velocities for 20 early-type (B8-A9) and 74 late-type (F2-M8) members of the ~5 Myr old Upper Scorpius OB Association derived from high dispersion optical spectra obtained with the High Resolution Echelle…
Our goal is to determine the rotational and magnetic-related activity properties of stars at different stages of evolution. We have focussed our attention on 6 young loose stellar associations within 100 pc and ages in the range 8-70 Myr:…
Despite the wide range of planet-star (mis)alignments in the mature population of transiting exoplanets, the small number of known young transiting planets are nearly all aligned with the rotation axes of their host stars, as determined by…
Spectroscopic follow-up of dozens of transiting planets has revealed the degree of alignment between the equators of stars and the orbits of the planets they host. Here we determine a method, applicable to spotted stars, that can reveal the…
We have obtained high resolution spectropolarimetric data for the planet-hosting star $\tau$ Bootis, using the ESPaDOnS spectropolarimeter at CFHT. A weak but clear Stokes $V$ signature is detected on three of the four nights of June 2006…
Hot-Jupiter planets must form at large separations from their host stars where the temperatures are cool enough for their cores to condense. They then migrate inwards to their current observed orbital separations. Different theories of how…
We present near-infrared spectropolarimetric observations of a sample of 43 weakly- to moderately-active M dwarfs, carried with SPIRou at the Canada-France-Hawaii Telescope in the framework of the SPIRou Legacy Survey from early 2019 to mid…
Although close-orbiting, massive exoplanets -- known as hot and warm Jupiters -- are among the most observationally accessible known planets, their formation pathways are still not universally agreed upon. One method to constrain the…
The spin-rotation of a planet arises from the accretion of angular momentum during its formation, but the details of this process are still unclear. In the solar system, the equatorial rotation velocities and spin angular momentum of the…
We discuss the spin-orbit orientation of the Fomalhaut planetary system composed of a central A4V star, a debris disk, and a recently discovered planetary companion. We use spectrally resolved, near-IR long baseline interferometry to obtain…
We present observations of the classical T Tauri star DO Tau collected with the near-infrared SPIRou spectropolarimeter and precision velocimeter at the Canada-France-Hawaii Telescope from early 2020 to late 2025. Circularly polarized…
The system of two transiting Neptune-sized planets around the bright, young M-dwarf AU Mic provides a unique opportunity to test models of planet formation, early evolution, and star-planet interaction. However, the intense magnetic…
AU Microscopii is a 12 Myr old M dwarf that harbors an optically thin, edge-on disk of dust. The scattered light surface brightness falls with projected distance b from the star as b^-a; within b = 43 AU, a = 1-2, while outside 43 AU, a =…
In an effort to measure the Rossiter-McLaughlin effect for the TRAPPIST-1 system, we performed high-resolution spectroscopy during transits of planets e, f, and b. The spectra were obtained with the InfraRed Doppler spectrograph on the…