Search Publications
The R-Process Alliance: First Magellan/MIKE Release from the Southern Search for R-process-enhanced Stars
Beers, Timothy C.; Placco, Vinicius M.; Hansen, Terese T. +9 more
Extensive progress has recently been made in our understanding of heavy-element production via the r-process in the universe, specifically with the first observed neutron star binary merger (NSBM) event associated with the gravitational-wave signal detected by LIGO, GW170817. The chemical abundance patterns of metal-poor r-process-enhanced stars p…
The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. III. Substructures in Protostellar Disks
Sheehan, Patrick D.; Megeath, S. Thomas; Looney, Leslie W. +2 more
The prevalence of substructures in ∼1-10 Myr old protoplanetary disks, which are often linked to planet formation, has raised the question of how early such features form and, as a corollary, how early planet formation begins. Here we present observations of seven protostellar disks (aged ∼ 0.1-1 Myr) from the Very Large Array/Atacama Large Millim…
X-Ray Scaling Relations for a Representative Sample of Planck-selected Clusters Observed with XMM-Newton
Lovisari, Lorenzo; Andrade-Santos, Felipe; Jones, Christine +7 more
We report the scaling relations derived by fitting the X-ray parameters determined from analyzing the XMM-Newton observations of 120 galaxy clusters in the Planck Early Sunyaev-Zel'dovich (SZ) sample spanning the redshift range of 0.059 < z < 0.546. We find that the slopes of all the investigated scaling relations significantly deviate from …
Flare Rates, Rotation Periods, and Spectroscopic Activity Indicators of a Volume-complete Sample of Mid- to Late-M Dwarfs within 15 pc
Winters, Jennifer G.; Medina, Amber A.; Irwin, Jonathan M. +1 more
We present a study of flare rates, rotation periods, and spectroscopic activity indicators of 125 single stars within 15 parsecs and with masses between 0.1 and 0.3 M⊙ observed during the first year of the TESS mission, with the goal of elucidating the relationship between these various magnetically connected phenomena. We gathered mult…
All the PAHs: An AKARI-Spitzer Cross-archival Spectroscopic Survey of Aromatic Emission in Galaxies
Baba, Shunsuke; Imanishi, Masatoshi; Lai, Thomas S. -Y. +2 more
We present a large sample of 2.5-38 µm galaxy spectra drawn from a cross-archival comparison in the AKARI-Spitzer Extragalactic Spectral Survey, and investigate a subset of 113 star-forming galaxies with prominent polycyclic aromatic hydrocarbon (PAH) emission spanning a wide range of star formation properties. With AKARI's extended 2.5-5 &m…
Standing on the Shoulders of Giants: New Mass and Distance Estimates for Betelgeuse through Combined Evolutionary, Asteroseismic, and Hydrodynamic Simulations with MESA
Kobayashi, Chiaki; Nomoto, Ken'ichi; Ireland, Michael +3 more
We conduct a rigorous examination of the nearby red supergiant Betelgeuse by drawing on the synthesis of new observational data and three different modeling techniques. Our observational results include the release of new, processed photometric measurements collected with the space-based Solar Mass Ejection Imager instrument prior to Betelgeuse's …
Double White Dwarf Merger Products among High-mass White Dwarfs
Toonen, Silvia; Cheng, Sihao; Cummings, Jeffrey D. +1 more
Double white dwarf (double-WD) binaries may merge within a Hubble time and produce high-mass WDs. Compared to other high-mass WDs, the double-WD merger products have higher velocity dispersion because they are older. With the power of Gaia data, we show strong evidence for double-WD merger products among high-mass WDs by analyzing the transverse-v…
EvryFlare. III. Temperature Evolution and Habitability Impacts of Dozens of Superflares Observed Simultaneously by Evryscope and TESS
Law, Nicholas M.; Corbett, Hank; Gonzalez, Ramses +8 more
Superflares may provide the dominant source of biologically relevant UV radiation to rocky habitable-zone M-dwarf planets (M-Earths), altering planetary atmospheres and conditions for surface life. The combined line and continuum flare emission has usually been approximated by a 9000 K blackbody. If superflares are hotter, then the UV emission may…
A Dynamical Survey of Stellar-mass Black Holes in 50 Milky Way Globular Clusters
Chatterjee, Sourav; Kremer, Kyle; Weatherford, Newlin C. +1 more
Recent numerical simulations of globular clusters (GCs) have shown that stellar-mass black holes (BHs) play a fundamental role in driving cluster evolution and shaping their present-day structure. Rapidly mass-segregating to the center of GCs, BHs act as a dynamical energy source via repeated superelastic scattering, delaying the onset of core col…
Metallicity and α-Element Abundance Gradients along the Sagittarius Stream as Seen by APOGEE
Cohen, Roger E.; Bizyaev, Dmitry; Brownstein, Joel R. +27 more
Using 3D positions and kinematics of stars relative to the Sagittarius (Sgr) orbital plane and angular momentum, we identify 166 Sgr stream members observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) that also have Gaia DR2 astrometry. This sample of 63/103 stars in the Sgr trailing/leading arm is combined with an APOGE…