Search Publications
Localizing Quasiperiodic Pulsations in Hard X-Ray, Microwave, and Lyα Emissions of an X6.4 Flare
Su, Yang; Li, Dong; Hong, Zhenxiang +1 more
We report the simultaneous observations of quasiperiodic pulsations (QPPs) in wavelengths of hard X-ray (HXR), microwave, Lyα, and ultraviolet (UV) emissions during the impulsive phase of an X6.4 flare on 2024 February 22 (SOL2024-02-22T22:08). The X6.4 flare shows three repetitive and successive pulsations in HXR and microwave wavebands, and they…
Imprints of the Local Bubble and Dust Complexity on Polarized Dust Emission
Tahani, Mehrnoosh; Clark, S. E.; Halal, George
Using 3D dust maps and Planck polarized dust emission data, we investigate the influence of the 3D geometry of the nearby interstellar medium (ISM) on the statistics of the dust polarization on large (
Measuring Tracers of Planet Formation in the Atmosphere of WASP-77A b: Substellar O/H and C/H Ratios, with a Stellar C/O Ratio and a Potentially Superstellar Ti/H Ratio
Changeat, Quentin; Edwards, Billy
We present a comprehensive atmospheric retrieval study of the hot Jupiter WASP-77A b using eclipse observations from the Hubble Space Telescope (HST) and JWST. Using atmospheric retrievals, the spectral features of H2O, CO, and TiO are identified, with volume mixing ratios estimated at log10(VMR) = ‑4.40 ${}_{-0.11}^{+0.14}$ …
A Test of Spectroscopic Age Estimates of White Dwarfs Using Wide WD+WD Binaries
Hermes, J. J.; van Saders, Jennifer L.; Tremblay, P. -E. +4 more
White dwarf stars have been used for decades as precise and accurate age indicators. This work presents a test of the reliability of white dwarf total ages when spectroscopic observations are available. We conduct follow-up spectroscopy of 148 individual white dwarfs in widely separated double-white-dwarf (WD+WD) binaries. We supplement the sample…
Single-star Warm-Jupiter Systems Tend to Be Aligned, Even around Hot Stellar Hosts: No T eff–λ Dependency
Butler, R. Paul; Quinn, Samuel N.; Rice, Malena +22 more
The stellar obliquity distribution of warm-Jupiter systems is crucial for constraining the dynamical history of Jovian exoplanets, as the warm Jupiters' tidal detachment likely preserves their primordial obliquity. However, the sample size of warm-Jupiter systems with measured stellar obliquities has historically been limited compared to that of h…
Automated Chemical Reaction Network Generation and Its Application to Exoplanet Atmospheres
Yang, Jeehyun; Hu, Renyu
With the advent of JWST and the spectroscopic characterization of exoplanet atmospheres in unprecedented detail, there is a demand for more complete pictures of chemical and photochemical reactions and their impacts on atmospheric composition. Traditionally, building reaction networks for (exo)planetary atmospheres involves manually tracking relev…
CHIANTI—An Atomic Database for Emission Lines—Paper. XVIII. Version 11, Advanced Ionization Equilibrium Models: Density and Charge Transfer Effects
Young, P. R.; Del Zanna, G.; Dere, K. P. +4 more
Version 11 of the CHIANTI database and software package is presented. Advanced ionization equilibrium models have been added for low charge states of seven elements (C, N, O, Ne, Mg, Si, and S), and represent a significant improvement especially when modeling the solar transition region. The models include the effects of higher electron density an…
Wide Binaries with White Dwarf or Neutron Star Companions Discovered from Gaia DR3 and LAMOST
Liu, Jifeng; Zhang, Haotong; Wang, Song +12 more
The Gaia Data Release 3 (DR3) mission has identified and provided about 440,000 binary systems with orbital solutions, offering a valuable resource for searching binaries including a compact component. By combining the Gaia DR3 data with radial velocities from the LAMOST spectroscopic survey, we identify three wide binaries possibly containing a c…
HSTPROMO Internal Proper-motion Kinematics of Dwarf Spheroidal Galaxies. I. Velocity Anisotropy and Dark Matter Cusp Slope of Draco
van der Marel, Roeland P.; Watkins, Laura L.; Bellini, Andrea +8 more
We analyze four epochs of Hubble Space Telescope imaging over 18 yr for the Draco dwarf spheroidal galaxy. We measure precise proper motions for hundreds of stars and combine these with existing line-of-sight (LOS) velocities. This provides the first radially resolved 3D velocity dispersion profiles for any dwarf galaxy. These constrain the intrin…
A Multiwavelength Survey of Nearby M Dwarfs: Optical and Near-ultraviolet Flares and Activity with Contemporaneous TESS, Kepler/K2, Swift, and HST Observations
Barclay, Thomas; Kowalski, Adam F.; Tristan, Isaiah I. +14 more
We present a comprehensive multiwavelength investigation into flares and activity in nearby M dwarf stars. We leverage the most extensive contemporaneous data set obtained through the Transiting Exoplanet Sky Survey, Kepler/K2, the Neil Gehrels Swift Observatory, and the Hubble Space Telescope, spanning the optical and near-ultraviolet (NUV) regim…