Results 41 to 50 of about 1,114 (198)

Confirmation of a Non‐Transiting Planet in the Habitable Zone of the Nearby M Dwarf L 98‐59

open access: yesAstronomische Nachrichten, EarlyView.
ABSTRACT Only 40 exoplanetary systems with five or more planets are currently known. These systems are crucial for our understanding of planet formation and planet‐planet interaction. The M dwarf L 98‐59 has previously been found to show evidence of five planets, three of which are transiting.
Paul I. Schwarz   +2 more
wiley   +1 more source

Strong Fractionation of Deuterium and Helium in Sub-Neptune Atmospheres along the Radius Valley

open access: yesThe Astrophysical Journal
We simulate atmospheric fractionation in escaping planetary atmospheres using IsoFATE , a new open-source numerical model. We expand the parameter space studied previously to planets with tenuous atmospheres that exhibit the greatest helium and deuterium
Collin Cherubim   +3 more
doaj   +1 more source

Commissioning an Inexpensive Off‐The‐Shelf Spectrograph for Radial‐Velocity Studies

open access: yesAstronomische Nachrichten, EarlyView.
ABSTRACT We present a way to set up an inexpensive out of the shelf spectrograph at a local observatory. Stability and resolution of the spectrograph are high enough for radial velocity determination of binary stars or determination of stellar characteristics. Even some exoplanets might be detectable via the radial velocity method.
Lukas Stock, Andreas Schrimpf
wiley   +1 more source

Oxidation of the Interiors of Carbide Exoplanets

open access: yesThe Planetary Science Journal, 2020
Astrophysical measurements have shown that some stars have sufficiently high carbon-to-oxygen ratios such that the planets they host would be mainly composed of carbides instead of silicates.
H. W. Horn   +5 more
doaj   +1 more source

Exploring Warm Jupiter Migration Pathways with Eccentricities. I. Catalog of Uniform Keplerian Fits to Radial Velocities of 200 Warm Jupiters

open access: yesThe Astrophysical Journal Supplement Series
Giant planets are expected to predominantly form beyond the water-ice line and occasionally undergo inward migration. Unlike hot Jupiters, which can result from high-eccentricity tidal migration, warm Jupiters between 0.1 and 1 au (≈10–365 days) are in ...
Marvin Morgan   +6 more
doaj   +1 more source

Conclusive Evidence for a Population of Water Worlds around M Dwarfs Remains Elusive

open access: yesThe Astrophysical Journal Letters, 2023
The population of small, close-in exoplanets is bifurcated into super-Earths and sub-Neptunes. We calculate physically motivated mass–radius relations for sub-Neptunes, with rocky cores and H/He-dominated atmospheres, accounting for their thermal ...
James G. Rogers   +2 more
doaj   +1 more source

Variability of Known Exoplanet Host Stars Observed by TESS

open access: yesThe Astronomical Journal, 2023
Both direct and indirect methods of exoplanet detection rely upon detailed knowledge of the potential host stars. Such stellar characterization allows for accurate extraction of planetary properties, as well as contributing to our overall understanding ...
Emilie R. Simpson   +5 more
doaj   +1 more source

Physical constraints for the evolution of life on exoplanets

open access: yes, 2018
Recently, many Earth-sized planets have been discovered around stars other than the Sun that might possess appropriate conditions for life. The development of theoretical methods for assessing the putative habitability of these worlds is of paramount importance, since it serves the dual purpose of identifying and quantifying what types of biosignatures
Lingam, Manasvi, Loeb, Abraham
openaire   +2 more sources

Altitude Profile and Isotopic Composition for N2 From Pioneer Venus Mass Spectra

open access: yesGeophysical Research Letters, Volume 52, Issue 23, 16 December 2025.
Abstract We report the highest resolution altitude profile and isotopic composition for N2 at Venus, to date. These results were obtained through re‐analysis of data acquired by the Pioneer Venus Large Probe Neutral Mass Spectrometer (LNMS). The N2 is non‐uniformly mixed across the clouds and sub‐cloud atmosphere (∼59–15 km) yet uniformly mixed across ...
R. Mogul, S. S. Limaye, M. J. Way
wiley   +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

open access: yesThe 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   +21 more
doaj   +1 more source

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