Search Publications
The Vertical Motion History of Disk Stars throughout the Galaxy
Ting, Yuan-Sen; Rix, Hans-Walter
It has long been known that the vertical motions of Galactic disk stars increase with stellar age, commonly interpreted as vertical heating through orbit scattering. Here we map the vertical actions of disk stars as a function of age (τ ≤slant 8 {Gyr}) and across a large range of Galactocentric radii, {\overline{R}}GC}, drawing on APOGE…
An Ideal Testbed for Planet-Disk Interaction: Two Giant Protoplanets in Resonance Shaping the PDS 70 Protoplanetary Disk
Baruteau, Clément; Bae, Jaehan; Teague, Richard +7 more
While numerical simulations have been playing a key role in the studies of planet-disk interaction, testing numerical results against observations has been limited so far. With the two directly imaged protoplanets embedded in its circumstellar disk, PDS 70 offers an ideal testbed for planet-disk interaction studies. Using two-dimensional hydrodyna…
Evidence for a Circumplanetary Disk around Protoplanet PDS 70 b
Pinte, Christophe; Casassus, Simon; Girard, Julien +5 more
We present the first observational evidence for a circumplanetary disk (CPD) around the protoplanet PDS 70 b, based on a new spectrum in the K-band acquired with Very Large Telescope/SINFONI. We tested three hypotheses to explain the spectrum: atmospheric emission from the planet with either (1) a single value of extinction, (2) a variable extinct…
Newly Discovered Bright z ∼ 9-10 Galaxies and Improved Constraints on Their Prevalence Using the Full CANDELS Area
Oesch, P. A.; Bouwens, R. J.; Illingworth, G. D. +5 more
We report the results of an expanded search for z ∼ 9-10 candidates over the ∼883 arcmin2 CANDELS+ERS fields. This study adds 147 arcmin2 to the search area we consider over the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS) COSMOS, UDS, and EGS fields, while expanding our selection to include source…
Diverse Variability of O and B Stars Revealed from 2-minute Cadence Light Curves in Sectors 1 and 2 of the TESS Mission: Selection of an Asteroseismic Sample
Neiner, Coralie; Buzasi, Derek; Bowman, Dominic M. +18 more
Uncertainties in stellar structure and evolution theory are largest for stars undergoing core convection on the main sequence. A powerful way to calibrate the free parameters used in the theory of stellar interiors is asteroseismology, which provides direct measurements of angular momentum and element transport. We report the detection and classif…
A New Generation of Cool White Dwarf Atmosphere Models. IV. Revisiting the Spectral Evolution of Cool White Dwarfs
Dufour, P.; Allard, N. F.; Blouin, S. +1 more
As a result of competing physical mechanisms, the atmospheric composition of white dwarfs changes throughout their evolution, a process known as spectral evolution. Because of the ambiguity of their atmospheric compositions and the difficulties inherent to the modeling of their dense atmospheres, no consensus exists regarding the spectral evolutio…
Connecting the Properties of Coronal Shock Waves with Those of Solar Energetic Particles
Vourlidas, Angelos; Kouloumvakos, Athanasios; Rouillard, Alexis P. +5 more
We develop and exploit a new catalog of coronal pressure waves modeled in 3D to study the potential role of these waves in accelerating solar energetic particles (SEPs) measured in situ. Our sample comprises modeled shocks and SEP events detected during solar cycle 24 observed over a broad range of longitudes. From the 3D reconstruction of shock w…
400 pc Imaging of a Massive Quasar Host Galaxy at a Redshift of 6.6
Hennawi, Joseph F.; Neeleman, Marcel; Rix, Hans-Walter +4 more
We report high spatial resolution (∼0.″076, 410 pc) Atacama Large Millimeter/submillimeter Array imaging of the dust continuum and the ionized carbon line [C II] in a luminous quasar host galaxy at z = 6.6, 800 million years after the big bang. Based on previous studies, this galaxy hosts a ∼1 × 109 {M}⊙ black hole and has a…
EvryFlare. I. Long-term Evryscope Monitoring of Flares from the Cool Stars across Half the Southern Sky
Law, Nicholas M.; Corbett, Hank; Fors, Octavi +5 more
We search for superflares from 4068 cool stars in 2+ yr of Evryscope photometry, focusing on those with high-cadence data from both Evryscope and the Transiting Exoplanet Survey Satellite (TESS). The Evryscope array of small telescopes observed 575 flares from 284 stars, with a median energy of 1034.0 erg. Since 2016, Evryscope has enab…
Chemical Abundances of Main-sequence, Turnoff, Subgiant, and Red Giant Stars from APOGEE Spectra. II. Atomic Diffusion in M67 Stars
Bovy, Jo; Pan, Kaike; Cunha, Katia +14 more
Chemical abundances for 15 elements (C, N, O, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, and Ni) are presented for 83 stellar members of the 4 Gyr old solar-metallicity open cluster M67. The sample contains stars spanning a wide range of evolutionary phases, from G dwarfs to red clump stars. The abundances were derived from near-IR (λ1.5-1.7 µ…