Search Publications
A unique hot Jupiter spectral sequence with evidence for compositional diversity
Fortney, Jonathan J.; Sing, David K.; López-Morales, Mercedes +11 more
The emergent spectra of close-in, giant exoplanets (`hot Jupiters') are expected to be distinct from those of self-luminous objects with similar effective temperatures because hot Jupiters are primarily heated from above by their host stars rather than internally from the release of energy from their formation1. Theoretical models predi…
BAT AGN Spectroscopic Survey. XX. Molecular Gas in Nearby Hard-X-Ray-selected AGN Galaxies
Lamperti, Isabella; Schawinski, Kevin; Saintonge, Amelie +23 more
We present the host-galaxy molecular gas properties of a sample of 213 nearby (0.01 < z < 0.05) hard-X-ray-selected active galactic nucleus (AGN) galaxies, drawn from the 70-month catalog of Swift's Burst Alert Telescope (BAT), with 200 new CO(2-1) line measurements obtained with the James Clerk Maxwell Telescope and the Atacama Pathfinder E…
Detection and Bulk Properties of the HR 8799 Planets with High-resolution Spectroscopy
Knutson, Heather; Duchêne, Gaspard; Fitzgerald, Michael P. +49 more
Using the Keck Planet Imager and Characterizer, we obtained high-resolution (R ~ 35,000) K-band spectra of the four planets orbiting HR 8799. We clearly detected H2O and CO in the atmospheres of HR 8799 c, d, and e, and tentatively detected a combination of CO and H2O in b. These are the most challenging directly imaged exopl…
Self-consistent Stellar Radial Velocities from LAMOST Medium-resolution Survey DR7
Tian, Hao; Zong, Weikai; Fu, Jian-Ning +12 more
Radial velocity (RV) is among the most fundamental physical quantities obtainable from stellar spectra and is rather important in the analysis of time-domain phenomena. LAMOST Medium-resolution Survey (MRS) DR7 contains five million single-exposure stellar spectra with spectral resolution R ~ 7500. However, the temporal variation of the RV zero-po…
New insight into the magnetism of degenerate stars from the analysis of a volume-limited sample of white dwarfs
Bagnulo, S.; Landstreet, J. D.
Many stars evolve into magnetic white dwarfs (MWDs), and observations may help to understand when the magnetic field appears at the stellar surface, if and how it evolves during the cooling phase, and, above all, what are the mechanisms that generate it. After obtaining new spectropolarimetric observations and combining them with previous literatu…
Tree-ring structure of Galactic bar resonance
Schönrich, Ralph; Chiba, Rimpei
Galaxy models have long predicted that galactic bars slow down by losing angular momentum to their postulated dark haloes. When the bar slows down, resonance sweeps radially outwards through the galactic disc while growing in volume, thereby sequentially capturing new stars at its surface/separatrix. Since trapped stars conserve their action of li…
Radii of young star clusters in nearby galaxies
Gnedin, Oleg Y.; Brown, Gillen
We measure the projected half-light radii of young star clusters in 31 galaxies from the Legacy Extragalactic UV Survey (LEGUS). We implement a custom pipeline specifically designed to be robust against contamination, which allows us to measure radii for 6097 clusters. This is the largest sample of young star cluster radii currently available. We …
Validation of the accuracy and precision of Gaia EDR3 parallaxes with globular clusters
Maíz Apellániz, J.; Barbá, R. H.; Pantaleoni González, M.
Context. The recent early third data release (EDR3) from the Gaia mission has produced parallaxes for 1.468 × 109 sources with better quality than those reported in the previous data release. Nevertheless, there are calibration issues with the data that require corrections to the published values and uncertainties.
Aims: We want to…
The Solar Neighborhood XLVIII: Nine Giant Planets Orbiting Nearby K Dwarfs, and the CHIRON Spectrograph's Radial Velocity Performance
Gies, Douglas R.; Quinn, Samuel N.; Henry, Todd J. +5 more
We report initial results of a large radial velocity survey of K dwarfs up to a distance of 50 pc from the solar system, to look for stellar, brown dwarf, and Jovian planets using radial velocities from the CHIRON spectrograph on the CTIO/SMARTS 1.5 m telescope. We identify three new exoplanet candidates orbiting host stars in the K dwarf survey a…
Magnetohydrodynamic Waves in Open Coronal Structures
Tian, H.; Wang, T. J.; Banerjee, D. +8 more
Modern observatories have revealed the ubiquitous presence of magnetohydrodynamic waves in the solar corona. The propagating waves (in contrast to the standing waves) are usually originated in the lower solar atmosphere which makes them particularly relevant to coronal heating. Furthermore, open coronal structures are believed to be the source reg…