Zobrazeno 1 - 10
of 55
pro vyhledávání: '"Kevin K. Hardegree-Ullman"'
Autor:
Jonathan Brande, Ian J. M. Crossfield, Laura Kreidberg, Caroline V. Morley, Travis Barman, Björn Benneke, Jessie L. Christiansen, Diana Dragomir, Jonathan J. Fortney, Thomas P. Greene, Kevin K. Hardegree-Ullman, Andrew W. Howard, Heather A. Knutson, Joshua D. Lothringer, Thomas Mikal-Evans
Publikováno v:
The Astrophysical Journal Letters, Vol 961, Iss 1, p L23 (2024)
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
Externí odkaz:
https://doaj.org/article/c10a878b465c46b29afe961002c6bd82
Autor:
Rebecca Gore, Steven Giacalone, Courtney D. Dressing, Emma V. Turtelboom, Ashley Schroeder, Charles D. Fortenbach, Kevin K. Hardegree-Ullman, Jon K. Zink, Andrew W. Mayo, Joshua E. Schlieder, Jessie L. Christiansen
Publikováno v:
The Astrophysical Journal Supplement Series, Vol 271, Iss 2, p 48 (2024)
We collected near-infrared spectra of 65 cool stars with the NASA Infrared Telescope Facility and analyzed them to calculate accurate metallicities and stellar parameters. The sample of 55 M dwarfs and 10 K dwarfs includes 25 systems with confirmed p
Externí odkaz:
https://doaj.org/article/a5d01ec8453e4ea8a0c7370fcf67d5cb
Autor:
Martin Schlecker, Dániel Apai, Tim Lichtenberg, Galen Bergsten, Arnaud Salvador, Kevin K. Hardegree-Ullman
Publikováno v:
The Planetary Science Journal, Vol 5, Iss 1, p 3 (2024)
Long-term magma ocean phases on rocky exoplanets orbiting closer to their star than the runaway greenhouse threshold—the inner edge of the classical habitable zone—may offer insights into the physical and chemical processes that distinguish poten
Externí odkaz:
https://doaj.org/article/0a00633499e7406cb9373fef091f4939
Autor:
Pierre-Alexis Roy, Björn Benneke, Caroline Piaulet, Michael A. Gully-Santiago, Ian J. M. Crossfield, Caroline V. Morley, Laura Kreidberg, Thomas Mikal-Evans, Jonathan Brande, Simon Delisle, Thomas P. Greene, Kevin K. Hardegree-Ullman, Travis Barman, Jessie L. Christiansen, Diana Dragomir, Jonathan J. Fortney, Andrew W. Howard, Molly R. Kosiarek, Joshua D. Lothringer
Publikováno v:
The Astrophysical Journal Letters, Vol 954, Iss 2, p L52 (2023)
Recent work on the characterization of small exoplanets has allowed us to accumulate growing evidence that sub-Neptunes with radii greater than ∼2.5 R _⊕ often host H _2 /He-dominated atmospheres both from measurements of their low bulk densities
Externí odkaz:
https://doaj.org/article/ed847f2e682e4dbb88a90ebdd8a6b386
Autor:
Jessie L. Christiansen, Jon K. Zink, Kevin K. Hardegree-Ullman, Rachel B. Fernandes, Philip F. Hopkins, Luisa M. Rebull, Kiersten M. Boley, Galen J. Bergsten, Sakhee Bhure
Publikováno v:
The Astronomical Journal, Vol 166, Iss 6, p 248 (2023)
The NASA K2 mission obtained high-precision time-series photometry for four young clusters, including the near-twin 600–800 Myr old Praesepe and Hyades clusters. Hot sub-Neptunes are highly prone to mass-loss mechanisms, given their proximity to th
Externí odkaz:
https://doaj.org/article/be67bcfe34e448c1b46a0e1c85514704
Autor:
Galen J. Bergsten, Ilaria Pascucci, Kevin K. Hardegree-Ullman, Rachel B. Fernandes, Jessie L. Christiansen, Gijs D. Mulders
Publikováno v:
The Astronomical Journal, Vol 166, Iss 6, p 234 (2023)
Reliable detections of Earth-sized planets in the habitable zone remain elusive in the Kepler sample, even for M dwarfs. The Kepler sample was once thought to contain a considerable number of M-dwarf stars ( T _eff < 4000 K), which hosted enough Eart
Externí odkaz:
https://doaj.org/article/aa38e6f579e04246ae36f46fd4faa1fb
Autor:
Rachel B. Fernandes, Kevin K. Hardegree-Ullman, Ilaria Pascucci, Galen J. Bergsten, Gijs D. Mulders, Katia Cunha, Eric E. Mamajek, Kyle A. Pearson, Gregory A. Feiden, Jason L. Curtis
Publikováno v:
The Astronomical Journal, Vol 166, Iss 4, p 175 (2023)
The demographics of young exoplanets can shed light on their formation and evolution processes. Exoplanet properties are derived from the properties of their host stars. As such, it is important to accurately characterize the host stars since any sys
Externí odkaz:
https://doaj.org/article/0666685995744670a5287c0a4e654e0d
Autor:
Kevin K. Hardegree-Ullman, Dániel Apai, Galen J. Bergsten, Ilaria Pascucci, Mercedes López-Morales
Publikováno v:
The Astronomical Journal, Vol 165, Iss 6, p 267 (2023)
Molecular oxygen is a strong indicator of life on Earth and may indicate biological processes on exoplanets too. Recent studies proposed that Earth-like O _2 levels might be detectable on nearby exoplanets using high-resolution spectrographs on futur
Externí odkaz:
https://doaj.org/article/01a60d99483548b992d33d1a36920286
Autor:
Jon K. Zink, Kevin K. Hardegree-Ullman, Jessie L. Christiansen, Erik A. Petigura, Kiersten M. Boley, Sakhee Bhure, Malena Rice, Samuel W. Yee, Howard Isaacson, Rachel B. Fernandes, Andrew W. Howard, Sarah Blunt, Jack Lubin, Ashley Chontos, Daria Pidhorodetska, Mason G. MacDougall
Publikováno v:
The Astronomical Journal, Vol 165, Iss 6, p 262 (2023)
In this study, we performed a homogeneous analysis of the planets around FGK dwarf stars observed by the Kepler and K2 missions, providing spectroscopic parameters for 310 K2 targets —including 239 Scaling K2 hosts—observed with Keck/HIRES. For o
Externí odkaz:
https://doaj.org/article/cfba459ac59f4ecd82791cd2ab56eb03
Autor:
Jeremy Dietrich, Dániel Apai, Martin Schlecker, Kevin K. Hardegree-Ullman, Benjamin V. Rackham, Nicolas Kurtovic, Karan Molaverdikhani, Paul Gabor, Thomas Henning, Wen-Ping Chen, Luigi Mancini, Alex Bixel, Aidan Gibbs, Richard P. Boyle, Samantha Brown-Sevilla, Remo Burn, Timmy N. Delage, Lizxandra Flores-Rivera, Riccardo Franceschi, Gabriele Pichierri, Sofia Savvidou, Jonas Syed, Ivan Bruni, Wing-Huen Ip, Chow-Choong Ngeow, An-Li Tsai, Chia-Lung Lin, Wei-Jie Hou, Hsiang-Yao Hsiao, Chi-Sheng Lin, Hung-Chin Lin, Ritvik Basant, Project EDEN
Publikováno v:
The Astronomical Journal, Vol 165, Iss 4, p 149 (2023)
Earth-sized exoplanets that transit nearby, late-spectral-type red dwarfs will be prime targets for atmospheric characterization in the coming decade. Such systems, however, are difficult to find via widefield transit surveys like Kepler or TESS. Con
Externí odkaz:
https://doaj.org/article/c5c7e471da4b4e448ec598b3407d09f5