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An Earth-sized Planet on the Verge of Tidal Disruption
Latham, David W.; Knutson, Heather A.; Huber, Daniel +94 more
TOI-6255 b (GJ 4256) is an Earth-sized planet (1.079 ± 0.065 R ⊕) with an orbital period of only 5.7 hr. With the newly commissioned Keck Planet Finder and CARMENES spectrographs, we determine the planet's mass to be 1.44 ± 0.14 M ⊕. The planet is just outside the Roche limit, with P orb/P Roche = 1.13 ±…
A JWST Survey for Planetary Mass Brown Dwarfs in IC 348
Luhman, K. L.; Tremblin, P.; Parker, R. J. +5 more
We have obtained images of the center of the star-forming cluster IC 348 with the James Webb Space Telescope and have identified brown dwarf candidates based on their photometry and point-like flux profiles. Low-resolution spectroscopy has been performed on four promising candidates, three of which have molecular absorption bands that indicate lat…
All Puffed Up: Exploring Ultra-diffuse Galaxy Origins Through Galaxy Interactions
Sand, David J.; Jones, Michael G.; Bennet, Paul +5 more
We present new follow-up observations of two ultra-diffuse galaxies (UDGs) selected for their distorted morphologies and tidal features, suggestive of tidal influence. Using Hubble Space Telescope Advanced Camera for Surveys F555W and F814W imaging, we identify 8 ± 2 globular clusters in KUG 0203-Dw1 and 6 ± 2 in KDG 013, abundances typical for no…
Medium-resolution 0.97–5.3 µm Spectra of Very Young Benchmark Brown Dwarfs with NIRSpec on Board the James Webb Space Telescope
Manjavacas, Elena; Giardino, G.; Valenti, Jeff +7 more
Spectra of young benchmark brown dwarfs with well-known ages are vital to characterize other brown dwarfs, for which ages are in general not known. These spectra are also crucial to test atmospheric models, which have the potential to provide detailed information about the atmospheres of these objects. However, to test atmospheric models optimally…
Kepler-discovered Multiple-planet Systems near Period Ratios Suggestive of Mean-motion Resonances Are Young
Schlaufman, Kevin C.; Hamer, Jacob H.
Before the launch of the Kepler Space Telescope, models of low-mass planet formation predicted that convergent type I migration would often produce systems of low-mass planets in low-order mean-motion resonances. Instead, Kepler discovered that systems of small planets frequently have period ratios larger than those associated with mean-motion res…
The POKEMON Speckle Survey of Nearby M Dwarfs. II. Observations of 1125 Targets
Hartman, Zachary D.; Ciardi, David R.; Lund, Michael B. +7 more
Stellar multiplicity is correlated with many stellar properties, yet multiplicity measurements have proven difficult for the M dwarfs—the most common type of star in our galaxy—due to their faintness and the fact that a reasonably complete inventory of later M dwarfs did not exist until recently. We have therefore carried out the Pervasive Overvie…
The PFS View of TOI-677 b: A Spin–Orbit Aligned Warm Jupiter in a Dynamically Hot System
Butler, R. Paul; Rice, Malena; Collins, Karen A. +9 more
TOI-677 b is part of an emerging class of "tidally detached" gas giants (a/R ⋆ ≳ 11) that exhibit large orbital eccentricities and yet low stellar obliquities. Such sources pose a challenge for models of giant planet formation, which must account for the excitation of high eccentricities without large changes in the orbital inclination.…
Two-dimensional Eclipse Mapping of the Hot-Jupiter WASP-43b with JWST MIRI/LRS
Helling, Christiane; Désert, Jean-Michel; Bell, Taylor J. +21 more
We present eclipse maps of the two-dimensional thermal emission from the dayside of the hot-Jupiter WASP-43b, derived from an observation of a phase curve with the JWST MIRI/LRS instrument. The observed eclipse shapes deviate significantly from those expected for a planet emitting uniformly over its surface. We fit a map to this deviation, constru…
The Multilayer Nature of Molecular Gas toward the Cygnus Region
Fang, Min; Chen, Zhiwei; Zhang, Shiyu +12 more
We study the physical properties and 3D distribution of molecular clouds (MCs) toward the Cygnus region using the MWISP CO survey and Gaia DR3 data. Based on Gaussian decomposition and clustering for 13CO lines, over 70% of the fluxes are recovered. With the identification result of 13CO structures, two models are designed to…
Evolution of Flare Activity in GKM Stars Younger Than 300 Myr over Five Years of TESS Observations
France, Kevin; Gagné, Jonathan; Feinstein, Adina D. +2 more
Stellar flares are short-duration (< hours) bursts of radiation associated with surface magnetic reconnection events. Stellar magnetic activity generally decreases as a function of both the age and Rossby number, R 0, a measure of the relative importance of the convective and rotational dynamos. Young stars (<300 Myr) have typical…