Related papers: Activity of TRAPPIST-1 analogue stars observed wit…

Flare flux reflect contribution from active regions rather than the whole hemisphere of a star. Unlike the amplitude of light-curves caused by starspots, the flare detection is independent of inclination. The two valuable properties of…

The TRAPPIST-1 system has 7 known terrestrial planets arranged compactly in a mean motion resonant chain around an ultra-cool central star, some within the estimated habitable zone. Given their short orbital periods of just a few days, it…

TRAPPIST-1 is a fantastic nearby (~39.14 light years) planetary system made of at least seven transiting terrestrial-size, terrestrial-mass planets all receiving a moderate amount of irradiation. To date, this is the most observationally…

Context. Massive substellar companions orbiting active low-mass stars are rare. They, however, offer an excellent opportunity to study the main mechanisms involved in the formation and evolution of substellar objects. Aims. We aim to…

We study variability through simultaneous optical and X-ray observations for the first time in a statistical sample of 256 M dwarfs. Such observations are required to constrain the flare frequency and energetics and to understand the…

TESS is revolutionising the search for planets orbiting bright and nearby stars. In sectors 3 and 4, TESS observed TOI-402 (TIC-120896927), a bright V=9.1 K1 dwarf also known as HD 15337, and found two transiting signals with period of 4.76…

The upcoming NASA Transiting Exoplanet Survey Satellite (TESS) will obtain space-based uninterrupted light curves for a large sample of bright white dwarfs distributed across the entire sky, providing a very rich resource for…

The two known planets in the planetary system of Teegarden's Star are among the most Earth-like exoplanets currently known. Revisiting this nearby planetary system with two planets in the habitable zone aims at a more complete census of…

We present a study of photometric flares on 154 low-mass ($\leq 0.2 \textrm{M}_{\odot}$) objects observed by the SPECULOOS-South Observatory from 1st June 2018 to 23rd March 2020. In this sample we identify 85 flaring objects, ranging in…

We investigate the origin of a flux increase found during a transit of TrES-1, observed with the HST. This feature in the HST light curve cannot be attributed to noise and is supposedly a dark area on the stellar surface of the host star…

The high quality light curves from the Transiting Exoplanet Survey Satellite (TESS) represent a unique laboratory for the study of stellar rotation, a fundamental observable driving stellar and planetary evolution, including planetary…

Recently, four additional Earth-mass planets were discovered orbiting the nearby ultracool M8 dwarf TRAPPIST-1, making a remarkable total of seven planets with equilibrium temperatures compatible with the presence of liquid water on their…

We report on a spectroscopic determination of the atmospheric parameters and chemical abundance of the parent star of the recently discovered transiting planet {TrES-2}. A detailed LTE analysis of a set of \ion{Fe}{1} and \ion{Fe}{2} lines…

Solar radio emission at low frequencies (<1 GHz) can provide valuable information on processes driving flares and coronal mass ejections (CMEs). Radio emission has been detected from active M dwarf stars, suggestive of much higher levels of…

Stellar magnetic activity, just like that of the Sun, manifests itself in the form of flares and spots on the surface of the star. In the solar case, the largest flares originate from large active regions. In this work, we present a study…

Analyzing all 120 s and 20 s light curves obtained by the TESS satellite up to Sector 69 - the end of the fifth year of observations - for all known white dwarfs and white dwarf candidates up to G=17.5 mag, we report the discovery of 32 new…

The variability of fast-rotating Oe/Be stars has been reported in detail in recent years. However, much less known about the behaviour of fast-rotating OB stars without known decretion disks, and hence it is difficult to identify the…

We present the results of a systematic search of the Transiting Exoplanet Survey Satellite (TESS) 2-min cadence data for new rapidly oscillating Ap (roAp) stars observed during the Cycle 2 phase of its mission. We find seven new roAp stars…

The ultracool dwarf star TRAPPIST-1 hosts seven Earth-size transiting planets, some of which could harbour liquid water on their surfaces. UV observations are essential to measure their high-energy irradiation, and to search for…

We simulate a radial velocity (RV) follow-up of the TRAPPIST-1 system, a faithful representative of M dwarfs hosting transiting Earth-sized exoplanets to be observed with SPIRou in the months to come. We generate a RV curve containing the…