Related papers: Lower-than-expected flare temperatures for TRAPPIS…
Exoplanet habitability remains a challenging field due to the large distances separating Earth from other stars. Using insights from biology and astrophysics, we studied the habitability of M-dwarf exoplanets by modeling their surface…
We present the results of a search for white light flares on the ~23,000 cool dwarfs in the Kepler Quarter 1 long cadence data. We have identified 373 flaring stars, some of which flare multiple times during the observation period. We…
We search for superflares from 4,068 cool stars in 2+ years of Evryscope photometry, focusing on those with high-cadence data from both Evryscope and TESS. The Evryscope array of small telescopes observed 575 flares from 284 stars, with a…
Understanding and characterising the magnetic activity of M dwarfs is of paramount importance in the search for Earth-like exoplanets orbiting them. Energetic stellar activity phenomena, such as flares or coronal mass ejections, which are…
Planets in close proximity to their parent star, such as those in the habitable zones around M dwarfs, could be subject to particularly high doses of particle radiation. We have carried out test-particle simulations of ~GeV protons to…
The TRAPPIST-1 system is comprised of seven Earth-sized rocky planets in small orbits around a Jupiter-sized ultracool dwarf star 12 parsec away. These planets cover an irradiation range similar to the range of the inner solar system. Three…
Kepler K2 long cadence data are used to study white light flares in a sample of 45 L dwarfs. We identified 11 flares on 9 L dwarfs with equivalent durations of (1.3 - 198) hr and total (UV/optical/IR) energies of $\geq$0.9 $\times$…
We obtained high-resolution spectra of the ultra-cool M-dwarf TRAPPIST-1 during the transit of its planet `b' using two high dispersion near-infrared spectrographs, IRD instrument on the Subaru 8.2m telescope and HPF instrument on the 10m…
Three Earth-sized exoplanets were recently discovered close to the habitable zone of the nearby ultracool dwarf star TRAPPIST-1. The nature of these planets has yet to be determined, since their masses remain unmeasured and no observational…
The planetary infrared excess (PIE) technique has the potential to efficiently detect and characterize the thermal spectra of both transiting and non-transiting exoplanets. However, the technique has not been evaluated on multiplanet…
We investigate the interior structures and cryovolcanic observability of the exoplanets TRAPPIST-1f, g, and h. Our aim is to determine which interior configurations can sustain subsurface liquid water oceans in thermal equilibrium and to…
Using the SDSS DR7 spectroscopic catalog, we searched the WISE AllWISE catalog to investigate the occurrence of warm dust, as inferred from IR excesses, around field M dwarfs (dMs). We developed SDSS/WISE color selection criteria to…
Low-mass M stars are plentiful in the Universe and often host small, rocky planets detectable with the current instrumentation. Recently, seven small planets have been discovered orbiting the ultracool dwarf…
We report results of an observing campaign to study the dwarf M flare star EV Lacertae. Between October 2021 and January 2022 we obtained concurrent B band photometry and low resolution spectroscopy of EV Lac on 39 occasions during 10 of…
Context. White-light stellar flares are proxies for some of the most energetic types of flares, but their triggering mechanism is still poorly understood. As they are associated with strong X and UV emission, their study is particularly…
Observations made using TESS revealed a sample of low mass stars which show a periodic modulation on a period $<0.2$~d. Surprisingly many of these Ultra Fast Rotating (UFR) stars showed no evidence of flare activity which would be expected…
Flares and CMEs are very powerful events in which energetic radiation and particles are ejected within a short time. These events thus can strongly affect planets that orbit these stars. This is particularly relevant for planets of M-stars,…
One of the most significant goals of modern science is establishing whether life exists around other suns. The most direct path towards its achievement is the detection and atmospheric characterization of terrestrial exoplanets with…
M dwarfs produce explosive flare emission in the near-UV and optical continuum, and the mechanism responsible for this phenomenon is not well-understood. We present a near-UV/optical flare spectrum from the rise phase of a secondary flare,…
Context. Planetary mass and radius data are showing a wide variety in densities of low-mass exoplanets. This includes sub-Neptunes, whose low densities can be explained with the presence of a volatile-rich layer. Water is one of the most…