Related papers: Spin-orbit alignment and magnetic activity in the …
Although the star itself is not He enriched, the periodicity and the variability in the UV wind lines of the pulsating B1 IV star beta Cep are similar to what is observed in magnetic He-peculiar B stars, suggesting that beta Cep is…
We report the systematic detection of magnetic fields in massive (M > 5 M$_\odot$) late-type supergiants, using spectropolarimetric observations obtained with ESPaDOnS at the Canada-France-Hawaii Telescope. Our observations reveal…
The geometries of near-resonant planetary systems offer a relatively pristine window into the initial conditions of exoplanet systems. Given that near-resonant systems have likely experienced minimal dynamical disruptions, the spin-orbit…
The transiting extrasolar planet XO-3b is remarkable, with a high mass and eccentric orbit. The unusual characteristics make it interesting to test whether its orbital plane is parallel to the equator of its host star, as it is observed for…
Massive stars are important building blocks of the Universe, and their stellar structure and evolution models are fundamental cornerstones of various fields in modern astrophysics. The precision of these models is limited by our lack of…
Understanding the orbits of giant planets is critical for testing planet formation models, particularly at wide separations greater than 10 au where traditional core accretion becomes inefficient. However, constraining orbits at these…
The surface rotation rates of young solar-type stars decrease rapidly with age from the end of the pre-main sequence though the early main sequence. This suggests that there is also an important change in the dynamos operating in these…
We present new radial-velocity measurements of HAT-P-13, a star with two previously known companions: a transiting giant planet "b" with an orbital period of 3 days, and a more massive object "c" on a 1.2 yr, highly eccentric orbit. For…
We performed a radial velocity (RV) monitoring of the 40 Myr old star DS Tuc A with HARPS at the ESO-3.6m to determine the planetary mass of its 8.14-days planet, first revealed by TESS. We also observed two planetary transits with HARPS…
Since the recent discovery of the directly imaged super-Jovian planet AF Lep b, several studies have been conducted to characterize its atmosphere and constrain its orbital parameters. AF Lep b has a measured dynamical mass of $3.68 \pm…
Accurate tracers of the stellar magnetic field and rotation are cornerstones for the study of M dwarfs and for reliable detection and characterization of their exoplanetary companions. Such measurements are particularly challenging for old,…
We have obtained new images of the protoplanetary disk orbiting TW Hya in visible, total intensity light with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST), using the newly commissioned BAR5 occulter.…
The spin-orbit angle between a stellar spin axis and its planetary orbital axis is a key diagnostic of planetary migration pathways, yet the mechanisms shaping the observed spin-orbit distribution remain incompletely understood. Combining…
A planet's orbital alignment places important constraints on how a planet formed and consequently evolved. The dominant formation pathway of ultra-short period planets ($P<1$ day) is particularly mysterious as such planets most likely…
We report the discovery of a circumstellar debris disk viewed nearly edge-on and associated with the young, K1 star BD+45$^{\circ}$598 using high-contrast imaging at 2.2$\mu$m obtained at the W.M.~Keck Observatory. We detect the disk in…
We present the direct imaging discovery of a giant planet orbiting the young star AF Lep, a 1.2 $M_{\odot}$ member of the 24 $\pm$ 3 Myr $\beta$ Pic moving group. AF Lep was observed as part of our ongoing high-contrast imaging program…
There have recently been detections of radio emission from low-mass stars, some of which are indicative of star-planet interactions. Motivated by these exciting new results, here we present stellar wind models for the active planet-hosting…
One manifestation of dynamo action on the Sun is the 22-yr magnetic cycle, exhibiting a polarity reversal and a periodic conversion between poloidal and toroidal fields. For M dwarfs, several authors claim evidence of activity cycles from…
We investigate how the observed large-scale surface magnetic fields of low-mass stars (~0.1 -- 2 Msun), reconstructed through Zeeman-Doppler imaging (ZDI), vary with age t, rotation and X-ray emission. Our sample consists of 104 magnetic…
Planets orbiting young, solar-type stars are embedded in a more energetic environment than that of the solar neighbourhood. They experience harsher conditions due to enhanced stellar magnetic activity and wind shaping the secular evolution…