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New Mass and Radius Constraints on the LHS 1140 Planets: LHS 1140 b Is either a Temperate Mini-Neptune or a Water World
DOI: 10.3847/2041-8213/ad1691 Bibcode: 2024ApJ...960L...3C

Wade, Gregg A.; Dang, Lisa; Cowan, Nicolas B. +43 more

The two-planet transiting system LHS 1140 has been extensively observed since its discovery in 2017, notably with Spitzer, HST, TESS, and ESPRESSO, placing strong constraints on the parameters of the M4.5 host star and its small temperate exoplanets, LHS 1140 b and c. Here, we reanalyze the ESPRESSO observations of LHS 1140 with the novel line-by-…

2024 The Astrophysical Journal
Gaia eHST 25
Muted Features in the JWST NIRISS Transmission Spectrum of Hot Neptune LTT 9779b
DOI: 10.3847/2041-8213/ad20e4 Bibcode: 2024ApJ...962L..20R

Johnstone, Doug; Dang, Lisa; Cowan, Nicolas B. +13 more

The hot Neptune desert is one of the most sparsely populated regions of the exoplanet parameter space, and atmosphere observations of its few residents can provide insights into how such planets have managed to survive in such an inhospitable environment. Here, we present transmission observations of LTT 9779 b, the only known hot Neptune to have …

2024 The Astrophysical Journal
JWST 25
Clouds and Clarity: Revisiting Atmospheric Feature Trends in Neptune-size Exoplanets
DOI: 10.3847/2041-8213/ad1b5c Bibcode: 2024ApJ...961L..23B

Fortney, Jonathan J.; Mikal-Evans, Thomas; Lothringer, Joshua D. +12 more

Over the last decade, precise exoplanet transmission spectroscopy has revealed the atmospheres of dozens of exoplanets, driven largely by observatories like the Hubble Space Telescope. One major discovery has been the ubiquity of atmospheric aerosols, often blocking access to exoplanet chemical inventories. Tentative trends have been identified, s…

2024 The Astrophysical Journal
eHST JWST 25
Multivariate Predictors of Lyman Continuum Escape. I. A Survival Analysis of the Low-redshift Lyman Continuum Survey
DOI: 10.3847/1538-4357/ad58b9 Bibcode: 2024ApJ...972...92J

Ferguson, Henry C.; Giavalisco, Mauro; Pentericci, Laura +19 more

To understand how galaxies reionized the Universe, we must determine how the escape fraction of Lyman continuum (LyC) photons (f esc) depends on galaxy properties. Using the z ∼ 0.3 Low-redshift Lyman Continuum Survey (LzLCS), we develop and analyze new multivariate predictors of f esc. These predictions use the Cox proportio…

2024 The Astrophysical Journal
eHST 23
LHS 1140 b Is a Potentially Habitable Water World
DOI: 10.3847/2041-8213/ad5204 Bibcode: 2024ApJ...968L..22D

Yang, Jeehyun; Hu, Renyu; Bello-Arufe, Aaron +1 more

LHS 1140 b is a small planet orbiting in the habitable zone of its M4.5V dwarf host. Recent mass and radius constraints have indicated that it has either a thick H2-rich atmosphere or substantial water by mass. Here we present a transmission spectrum of LHS 1140 b between 1.7 and 5.2 µm, obtained using the NIRSpec instrument on JW…

2024 The Astrophysical Journal
JWST 23
Multivariate Predictors of Lyman Continuum Escape. II. Predicting Lyman Continuum Escape Fractions for High-redshift Galaxies
DOI: 10.3847/1538-4357/ad5557 Bibcode: 2024ApJ...973..111J

Ferguson, Henry C.; Giavalisco, Mauro; Pentericci, Laura +19 more

JWST is uncovering the properties of ever-increasing numbers of galaxies at z > 6, during the epoch of reionization. Connecting these observed populations to the process of reionization requires understanding how efficiently they produce Lyman continuum (LyC) photons and what fraction (f esc) of these photons escape into the intergal…

2024 The Astrophysical Journal
eHST 23
SN 2023ixf in Messier 101: The Twilight Years of the Progenitor as Seen by Pan-STARRS
DOI: 10.3847/1538-4357/ad2df7 Bibcode: 2024ApJ...965...93R

Kilpatrick, Charles D.; Chambers, Kenneth C.; Coulter, David A. +28 more

The nearby type II supernova, SN 2023ixf in M101 exhibits signatures of early time interaction with circumstellar material in the first week postexplosion. This material may be the consequence of prior mass loss suffered by the progenitor, which possibly manifested in the form of a detectable presupernova outburst. We present an analysis of long-b…

2024 The Astrophysical Journal
eHST 23
Shiva and Shakti: Presumed Proto-Galactic Fragments in the Inner Milky Way
DOI: 10.3847/1538-4357/ad1885 Bibcode: 2024ApJ...964..104M

Rix, Hans-Walter; Malhan, Khyati

Using Gaia Data Release 3 astrometry and spectroscopy, we study two new substructures in the orbit–metallicity space of the inner Milky Way: Shakti and Shiva. They were identified as two confined, high-contrast overdensities in the (L z , E) distribution of bright (G < 16) and metal-poor (‑2.5 < [M/H] < ‑ 1.0) stars. Both have…

2024 The Astrophysical Journal
Gaia 22
On the Mesoscale Structure of Coronal Mass Ejections at Mercury's Orbit: BepiColombo and Parker Solar Probe Observations
DOI: 10.3847/1538-4357/ad1ab4 Bibcode: 2024ApJ...963..108P

Dresing, Nina; Nieves-Chinchilla, Teresa; Weiss, Andreas J. +27 more

On 2022 February 15, an impressive filament eruption was observed off the solar eastern limb from three remote-sensing viewpoints, namely, Earth, STEREO-A, and Solar Orbiter. In addition to representing the most-distant observed filament at extreme ultraviolet wavelengths—captured by Solar Orbiter's field of view extending to above 6 R

2024 The Astrophysical Journal
BepiColombo SOHO SolarOrbiter 22
MIDIS: The Relation between Strong (Hβ + [O III]) Emission, Star Formation, and Burstiness around the Epoch of Reionization
DOI: 10.3847/1538-4357/ad4eb2 Bibcode: 2024ApJ...969..159C

Nørgaard-Nielsen, H. U.; Östlin, G.; Güdel, M. +25 more

We investigate the properties of strong (Hβ + [O III]) emitters before and after the end of the "Epoch of Reionization" from z = 8 to z = 5.5. We make use of ultradeep JWST/NIRCam imaging in the parallel field (P2) of the MIRI Deep Imaging Survey (MIDIS) in the Hubble eXtreme Deep Field (H-XDF), in order to select prominent (Hβ + [O III]) emitters…

2024 The Astrophysical Journal
eHST JWST 22