Search Publications
X-ray irradiation and evaporation of the four young planets around V1298 Tau
Mallonn, M.; Poppenhaeger, K.; Ketzer, L.
Planets around young stars are thought to undergo atmospheric evaporation due to the high magnetic activity of the host stars. Here we report on X-ray observations of V1298 Tau, a young star with four transiting exoplanets. We use X-ray observations of the host star with Chandra and ROSAT to measure the current high-energy irradiation level of the…
Calibration of the Hα Age-Activity Relation for M Dwarfs
Angus, Ruth; Kiman, Rocio; Mann, Andrew W. +6 more
In this work, we calibrate the relationship between Hα emission and M dwarf ages. We compile a sample of 892 M dwarfs with Hα equivalent width (Hα EW) measurements from the literature that are either comoving with a white dwarf of known age (21 stars) or in a known young association (871 stars). In this sample we identify 7 M dwarfs that are new c…
TESS Hunt for Young and Maturing Exoplanets (THYME). IV. Three Small Planets Orbiting a 120 Myr Old Star in the Pisces-Eridanus Stream
Torres, Guillermo; Vanderburg, Andrew; Gorjian, Varoujan +50 more
Young exoplanets can offer insight into the evolution of planetary atmospheres, compositions, and architectures. We present the discovery of the young planetary system TOI 451 (TIC 257605131, Gaia DR2 4844691297067063424). TOI 451 is a member of the 120 Myr old Pisces-Eridanus stream (Psc-Eri). We confirm membership in the stream with its kinemati…
SOAR TESS Survey. II. The Impact of Stellar Companions on Planetary Populations
Ziegler, Carl; Tokovinin, Andrei; Mann, Andrew W. +3 more
We present the results of the second year of exoplanet candidate host speckle observations from the SOAR TESS survey. We find 89 of the 589 newly observed TESS planet candidate hosts have companions within 3″, resulting in light-curve dilution, that, if not accounted for, leads to underestimated planetary radii. We combined these observations with…
A Number of nearby Moving Groups May Be Fragments of Dissolving Open Clusters
Faherty, Jacqueline K.; Gagné, Jonathan; Moranta, Leslie +1 more
We propose that 14 co-moving groups of stars uncovered by Kounkel & Covey may be related to known nearby moving groups and bridge those and nearby open clusters with similar ages and space velocities. This indicates that known nearby moving groups may be spatially much more extended than previously thought, and some of them might be parts of t…
First year of energetic particle measurements in the inner heliosphere with Solar Orbiter's Energetic Particle Detector
Kulkarni, S. R.; Lario, D.; Vainio, R. +45 more
Context. Solar Orbiter strives to unveil how the Sun controls and shapes the heliosphere and fills it with energetic particle radiation. To this end, its Energetic Particle Detector (EPD) has now been in operation, providing excellent data, for just over a year.
Aims: EPD measures suprathermal and energetic particles in the energy range from …
CHEOPS precision phase curve of the Super-Earth 55 Cancri e
Guterman, P.; Alonso, R.; Deleuil, M. +79 more
Context. 55 Cnc e is a transiting super-Earth (radius 1.88 R⊕ and mass 8 M⊕) orbiting a G8V host star on a 17-h orbit. Spitzer observations of the planet's phase curve at 4.5 µm revealed a time-varying occultation depth, and MOST optical observations are consistent with a time-varying phase curve amplitude and phase off…
Formation and dynamics of water clouds on temperate sub-Neptunes: the example of K2-18b
Bézard, B.; Charnay, B.; Leconte, J. +3 more
Context. Hubble Space Telescope (HST) spectroscopic transit observations of the temperate sub-Neptune K2-18b were interpreted as the presence of water vapour with potential water clouds. 1D modelling studies also predict the formation of water clouds in K2-18b's atmosphere in some conditions. However, such models cannot predict the cloud cover, wh…
Introducing the LBT Imaging of Galactic Halos and Tidal Structures (LIGHTS) survey. A preview of the low surface brightness Universe to be unveiled by LSST
Trujillo, Ignacio; Sand, David J.; Zaritsky, Dennis +10 more
We present the first results of the LBT Imaging of Galaxy Haloes and Tidal Structures (LIGHTS) survey. LIGHTS is an ongoing observational campaign with the 2 × 8.4 m Large Binocular Telescope (LBT) aiming to explore the stellar haloes and the low surface brightness population of satellites down to a depth of µV ∼ 31 mag arcsec
Evolution of the Exoplanet Size Distribution: Forming Large Super-Earths Over Billions of Years
Angus, Ruth; Foreman-Mackey, Daniel; Bedell, Megan +8 more
The radius valley, a bifurcation in the size distribution of small, close-in exoplanets, is hypothesized to be a signature of planetary atmospheric loss. Such an evolutionary phenomenon should depend on the age of the star-planet system. In this work, we study the temporal evolution of the radius valley using two independent determinations of host…