794 citations · 10k across the 110 of their papers we have counts for
11 papers · 1 filter
r-process Abundance Patterns in the Globular Cluster M92
Evan N. Kirby, Alexander P. Ji, Mikhail Kovalev
Whereas light element abundance variations are a hallmark of globular clusters, there is little evidence for variation in neutron-capture elements. A significant exception is M15,…
Empirical Constraints on Core Collapse Supernova Yields using Very Metal Poor Damped Lyman Alpha Absorbers
Evan Haze Nuñez, Evan N. Kirby, Charles C. Steidel
We place empirical constraints on the yields from zero- and low-metallicity core collapse supernovae (CCSNe) using abundances measured in very metal-poor (VMP; [Fe/H] )…
The Stars in M15 Were Born with the r-process
Evan N. Kirby, Gina Duggan, Enrico Ramirez-Ruiz +1
High-resolution spectroscopy of stars on the red giant branch (RGB) of the globular cluster M15 has revealed a large (~1 dex) dispersion in the abundances of r-process elements, li…
Manganese Indicates a Transition from Sub- to Near-Chandrasekhar Type Ia Supernovae in Dwarf Galaxies
Mithi A. C. de los Reyes, Evan N. Kirby, Ivo R. Seitenzahl +1
Manganese (Mn) abundances are sensitive probes of the progenitors of Type Ia supernovae (SNe). In this work, we present a catalog of manganese abundances in dwarf spheroidal satell…
Evidence for Sub-Chandrasekhar Type Ia Supernovae from Stellar Abundances in Dwarf Galaxies
Evan N. Kirby, Justin L. Xie, Rachel Guo +6
There is no consensus on the progenitors of Type Ia supernovae (SNe Ia) despite their importance for cosmology and chemical evolution. We address this question by using our previou…
Catalog of Chromium, Cobalt, and Nickel Abundances in Globular Clusters and Dwarf Galaxies
Evan N. Kirby, Justin L. Xie, Rachel Guo +2
We present measurements of the abundances of chromium, cobalt, and nickel in 4113 red giants, including 2277 stars in globular clusters, 1820 stars in the Milky Way's dwarf satelli…
An investigation of the formation and line properties of MgH in 3D hydrodynamical model stellar atmospheres
Anders O. Thygesen, Evan N. Kirby, Andrew J. Gallagher +4
Studies of the isotopic composition of magnesium in cool stars have so far relied upon the use of one-dimensional (1D) model atmospheres. Since the isotopic ratios derived are base…
Lithium-Rich Giants in Globular Clusters
Evan N. Kirby, Puragra Guhathakurta, Andrew J. Zhang +5
Although red giants deplete lithium on their surfaces, some giants are Li-rich. Intermediate-mass asymptotic giant branch (AGB) stars can generate Li through the Cameron-Fowler con…
Discovery of Super-Li Rich Red Giants in Dwarf Spheroidal Galaxies
Evan Kirby, Xiaoting Fu, Puragra Guhathakurta +1
Stars destroy lithium (Li) in their normal evolution. The convective envelopes of evolved red giants reach temperatures of millions of K, hot enough for the 7Li(p,alpha)4He reactio…
Characterizing the Cool KOIs III. KOI-961: A Small Star with Large Proper Motion and Three Small Planets
Philip S. Muirhead, John Asher Johnson, Kevin Apps +21
We present the characterization of the star KOI 961, an M dwarf with transit signals indicative of three short-period exoplanets, originally discovered by the Kepler Mission. We pr…
Grids of ATLAS9 Model Atmospheres and MOOG Synthetic Spectra
Evan N. Kirby
A grid of ATLAS9 model atmospheres has been computed, spanning 3500 K <= T_eff <= 8000 K, 0.0 <= log g <= 5.0, -4.0 <= [M/H] <= 0.0, and -0.8 < [alpha/Fe] <= +1.2. These parameters…