Results 81 to 90 of about 6,459 (144)

Three Years of High-contrast Imaging of the PDS 70 b and c Exoplanets at Hα with MagAO-X: Evidence of Strong Protoplanet Hα Variability and Circumplanetary Dust

The Astronomical Journal
We present 3 yr of high-contrast imaging of the PDS 70 b and c accreting protoplanets with the new extreme AO system MagAO-X as part of the MaxProtoPlanetS survey of H α protoplanets.
Laird M. Close, Jared R. Males, Jialin Li, Sebastiaan Y. Haffert, Joseph D. Long, Alexander D. Hedglen, Alycia J. Weinberger, Katherine B. Follette, Daniel Apai, Rene Doyon, Warren Foster, Victor Gasho, Kyle Van Gorkom, Olivier Guyon, Maggie Y. Kautz, Jay Kueny, Jennifer Lumbres, Avalon McLeod, Eden McEwen, Clarissa Pavao, Logan Pearce, Laura Perez, Lauren Schatz, Judit Szulágyi, Kevin Wagner, Ya-Lin Wu   +25 more
doaj   +1 more source

Far-ultraviolet Flares and Variability of the Young M Dwarf AU Mic: A Nondetection of Planet C in Transit at Lyα

The Astronomical Journal
Atmospheric escape’s potential to shape the exoplanet population motivates detailed observations of systems actively undergoing escape. AU Mic is a young and active M dwarf hosting two close-in transiting sub- to Neptune-sized planets. Atmospheric escape
Keighley E. Rockcliffe, Elisabeth R. Newton, Allison Youngblood, Girish M. Duvvuri, Emily A. Gilbert, Peter Plavchan, Peter Gao, Hans-R. Müller, Adina D. Feinstein, Thomas Barclay, Eric D. Lopez   +10 more
doaj   +1 more source

The single beacon: progresses in understanding Earth as an exoplanet using DSCOVR/EPIC observations

Frontiers in Remote Sensing
Almost 6000 exoplanets have thus far been confirmed, revolutionizing our understanding of planetary habitability. Yet, despite the identification of Earth-like exoplanets, definitive evidence of extraterrestrial life remains elusive.
Xun Jian, Xun Jian, Lixiang Gu, Siteng Fan, Stuart J. Bartlett, Jiani Yang, Jonathan H. Jiang, Yangcheng Luo, Yuk L. Yung, Yuk L. Yung   +9 more
doaj   +1 more source

Planetary Rhythms: Synchronous Circulation on Variably Irradiated Asynchronous Planets

The Astrophysical Journal
Tidal locking of planets to their host stars results in an atmospheric circulation with a hotspot fixed to the frame of reference of the planet. On the other hand, asynchronously rotating planets feature moving hotspots either lagging or leading the ...
Deepayan Banik
doaj   +1 more source

Detecting Atmospheric CO2 Trends as Population-level Signatures for Long-term Stable Water Oceans and Biotic Activity on Temperate Terrestrial Exoplanets

The Astrophysical Journal
Identifying key observables is essential for enhancing our knowledge of exoplanet habitability and biospheres, as well as improving future mission capabilities.
Janina Hansen, Daniel Angerhausen, Sascha P. Quanz, Derek Vance, Björn S. Konrad, Emily O. Garvin, Eleonora Alei, Jens Kammerer, Felix A. Dannert   +8 more
doaj   +1 more source

Atmospheric Waves Driving Variability and Cloud Modulation on a Planetary-mass Object

The Astrophysical Journal
Planetary-mass objects and brown dwarfs at the transition ( T _eff ∼ 1300 K) from relatively red L dwarfs to bluer mid-T dwarfs show enhanced spectrophotometric variability.
Michael K. Plummer, Ji Wang, Étienne Artigau, René Doyon, Genaro Suárez   +4 more
doaj   +1 more source

The Polar Vortex Hypothesis: Evolving, Spectrally Distinct Polar Regions Explain Short- and Long-term Light-curve Evolution and Color–Inclination Trends in Brown Dwarfs and Giant Exoplanets

The Astrophysical Journal Letters
Recent studies revealed viewing-angle-dependent color and spectral trends in brown dwarfs, as well as long-term photometric variability (∼100 hr). The origins of these trends are yet unexplained.
Nguyen Fuda, Dániel Apai
doaj   +1 more source

Planetary Habitability Under the Light of a Rapidly Changing Star

The Astronomical Journal
Planetary atmospheric energy budgets primarily depend on stellar incident flux. However, stellar variability can have major consequences for the evolution of planetary climates. In this work, we evaluate how stellar variability influences the equilibrium
Tara Fetherolf, Sadie G. Welter, Colby M. Ostberg, Stephen R. Kane, Rory Barnes, Emilie R. Simpson   +5 more
doaj   +1 more source

Pursuing Truth: Improving Retrievals on Mid-infrared Exo-Earth Spectra with Physically Motivated Water Abundance Profiles and Cloud Models

The Astrophysical Journal
Atmospheric retrievals are widely used to constrain exoplanet properties from observed spectra. We investigate how the common nonphysical retrieval assumptions of vertically constant molecule abundances and cloud-free atmospheres affect our ...
Björn S. Konrad, Sascha P. Quanz, Eleonora Alei, Robin Wordsworth   +3 more
doaj   +1 more source

Earth-like Exoplanets in Spin–Orbit Resonances: Climate Dynamics, 3D Atmospheric Chemistry, and Observational Signatures

The Planetary Science Journal
Terrestrial exoplanets around M- and K-type stars are important targets for atmospheric characterization. Such planets are likely tidally locked with the order of spin–orbit resonances (SORs) depending on eccentricity. We explore the impact of SORs on 3D
Marrick Braam, Paul I. Palmer, Leen Decin, Nathan J. Mayne, James Manners, Sarah Rugheimer   +5 more
doaj   +1 more source