Results 61 to 70 of about 700 (166)

Stellar Spectroscopy during Exoplanet Transits: Dissecting fine structure across stellar surfaces

, 2014
Differential spectroscopy during exoplanet transits permits to reconstruct spectra of small stellar surface portions that successively become hidden behind the planet. The center-to-limb behavior of stellar line shapes, asymmetries and wavelength shifts will enable detailed tests of 3-dimensional hydrodynamic models of stellar atmospheres, such that ...
Dravins, Dainis, Ludwig, Hans-Günter, Dahlén, Erik, Pazira, Hiva   +3 more
openaire   +2 more sources

Helium Depletion in Escaping Atmospheres of Sub-Neptunes: A Signature of Primary-to-secondary Transition

The Astrophysical Journal
Short-period sub-Neptunes are common in extrasolar systems. These sub-Neptunes are generally thought to have primary atmospheres of protoplanetary-disk gas origin.
Issei Kobayashi, Hiroyuki Kurokawa, Laura Schaefer, Satoshi Okuzumi   +3 more
doaj   +1 more source

A Metal-poor Atmosphere with a Hot Interior for a Young Sub-Neptune Progenitor: JWST/NIRSpec Transmission Spectrum of V1298 Tau b

The Astronomical Journal
We present the JWST/NIRSpec G395H transmission spectrum of the young (10–30 Myr) transiting planet V1298 Tau b (9.85 ± 0.35 R _⊕ , T _eq  = 670 K). Combined Hubble Space Telescope and JWST observations reveal a haze-free, H/He-dominated atmosphere with a
Saugata Barat, Jean-Michel Désert, Sagnick Mukherjee, Jayesh M. Goyal, Qiao Xue, Yui Kawashima, Allona Vazan, William Misener, Hilke E. Schlichting, Jonathan J. Fortney, Jacob L. Bean, Swaroop Avarsekar, Gregory W. Henry, Robin Baeyens, Michael R. Line, John H. Livingston, Trevor David, Erik A. Petigura, James T. Sikora, Hinna Shivkumar, Adina D. Feinstein, Antonija Oklopčić   +21 more
doaj   +1 more source

A Fast, Parallelized, GPU-accelerated Photochemical Model, XODIAC, with Built-in Equilibrium Chemistry and Multiple Chemical Networks for Exoplanetary Atmospheres

The Astrophysical Journal
The launch of the James Webb Space Telescope has delivered high-quality atmospheric observations and expanded the known chemical inventory of exoplanetary atmospheres, opening new avenues for atmospheric chemistry modeling to interpret these data.
Priyankush Ghosh, Sambit Mishra, Shubham Dey, Debayan Das, P. B. Rimmer, Liton Majumdar   +5 more
doaj   +1 more source

The Uncertainty in Water Mass Fraction of Wet Planets

The Astrophysical Journal
Planets with masses between Earth and Neptune often have radii that imply the presence of volatiles, suggesting that water may be abundant in their interiors.
Michael Lozovsky
doaj   +1 more source

Seasonal Changes in the Atmosphere of HD 80606 b Observed with JWST’s NIRSpec/G395H

The Astronomical Journal
High-eccentricity gas giant planets serve as unique laboratories for studying the thermal and chemical properties of H/He-dominated atmospheres. One of the most extreme cases is HD 80606 b—a hot Jupiter orbiting a Sun-like star with an eccentricity of 0 ...
James T. Sikora, Jason F. Rowe, Jared Splinter, Saugata Barat, Lisa Dang, Nicolas B. Cowan, Thomas Barclay, Knicole D. Colón, Jean-Michel Désert, Stephen R. Kane, Joe Llama, Hinna Shivkumar, Keivan G. Stassun, Elisa V. Quintana   +13 more
doaj   +1 more source

Exoplanet Technosignature Detection of Orbital Terraforming Mirror Structures

The search for technosignatures no longer rests solely on radio signals. Modern wide-field surveys now make it possible to detect engineered structures at interstellar distances. Among the most promising of these are space-based mirrors, as large reflective constructs designed to manipulate planetary climates by increasing or reducing incoming sunlight.
openaire   +1 more source

A Panchromatic Characterization of the Evening and Morning Atmosphere of WASP-107 b: Composition and Cloud Variations, and Insight into the Effect of Stellar Contamination

The Astronomical Journal
Limb-resolved transmission spectroscopy has the potential to transform our understanding of exoplanetary atmospheres. By separately measuring the transmission spectra of the evening and morning limbs, these atmospheric regions can be individually ...
Matthew M. Murphy, Thomas G. Beatty, Everett Schlawin, Taylor J. Bell, Michael Radica, Thomas D. Kennedy, Nishil Mehta, Luis Welbanks, Michael R. Line, Vivien Parmentier, Thomas P. Greene, Sagnick Mukherjee, Jonathan J. Fortney, Kazumasa Ohno, Lindsey Wiser, Anastasia Triantafillides, Emily Rauscher, Isaac R. Edelman, Marcia J. Rieke   +18 more
doaj   +1 more source

JWST/NIRISS Reveals the Water-rich “Steam World” Atmosphere of GJ 9827 d

The Astrophysical Journal Letters
With sizable volatile envelopes but smaller radii than the solar system ice giants, sub-Neptunes have been revealed as one of the most common types of planet in the galaxy. While the spectroscopic characterization of larger sub-Neptunes (2.5–4 R _⊕ ) has
Caroline Piaulet-Ghorayeb, Björn Benneke, Michael Radica, Eshan Raul, Louis-Philippe Coulombe, Eva-Maria Ahrer, Daria Kubyshkina, Ward S. Howard, Joshua Krissansen-Totton, Ryan J. MacDonald, Pierre-Alexis Roy, Amy Louca, Duncan Christie, Marylou Fournier-Tondreau, Romain Allart, Yamila Miguel, Hilke E. Schlichting, Luis Welbanks, Charles Cadieux, Caroline Dorn, Thomas M. Evans-Soma, Jonathan J. Fortney, Raymond Pierrehumbert, David Lafrenière, Lorena Acuña, Thaddeus Komacek, Hamish Innes, Thomas G. Beatty, Ryan Cloutier, René Doyon, Anna Gagnebin, Cyril Gapp, Heather A. Knutson   +32 more
doaj   +1 more source

Helium Escape in Context: Comparative Signatures of Four Close-in Exoplanets

The Astrophysical Journal
Observations of escaping atmospheres on close-in exoplanets show a wide range in the strength and morphology of He I 10830 Å and H I absorption. Scaling relations attempt to link the He I signal to X-ray and UV irradiation, mass loss, and bulk planetary ...
Anna Ruth Taylor, Tommi T. Koskinen, Chenliang Huang, Anthony Arfaux, Panayotis Lavvas   +4 more
doaj   +1 more source