36 citations · 94 across the 45 of their papers we have counts for
30 papers · 1 filter
Enhanced Mass Transfer from Extended Shock-Supported Stellar Chromospheres
Soumyadeep Bhattacharjee, Jim Fuller, Kareem El-Badry
Mass transfer (MT) in binary systems is a crucial and complex process. Even before the donor's photosphere fills its Roche lobe, matter from its outer atmosphere can reach the inne…
Discovery of a Nearby Ultra-fast Magnetic White Dwarf Propeller: Common Pathways to Magnetic Cataclysmic Variables
Antonio C. Rodriguez, Kareem El-Badry, R. Michael Rich +11
The fastest spinning white dwarfs (WDs), which approach break-up speeds, are found in close binary systems. In the two known magnetic WD ``propellers'', AE~Aqr and LAMOST J0240+195…
A concordance model of neutron star kicks
Cheyanne Shariat, Kareem El-Badry, Smadar Naoz
Neutron stars (NSs) receive natal kicks during supernovae that affect their survival in binaries and motion through the Galaxy. The global distribution of these kick velocities acr…
Gaia neutron stars: demographics, birth rates, and connections to other neutron star populations
Cheyanne Shariat, Natsuko Yamaguchi, Kareem El-Badry +1
Gaia DR3 revealed a new class of neutron stars (NSs) in au-scale orbits with solar-type companions. How these 'Gaia NSs' form remains unclear, and constraining their intrinsic popu…
Beyond what's observed: hierarchical inference of Gaia astrometric compact-object binaries
Natsuko Yamaguchi, Kareem El-Badry, Reed Essick +3
Astrometry from the Gaia mission has revealed a large and homogeneous population of binaries containing compact objects, including more than 3000 white dwarf--main sequence (WDMS)…
The long period radio transient ASKAP J1448-68 is a cataclysmic variable
Geoffrey Mo, Akash Anumarlapudi, Iris de Ruiter +8
Wide-field time-domain radio surveys have recently unveiled a new class of Galactic radio emitter: long period radio transients (LPTs). Despite the rapid pace of discovery, their o…
Discovery of over a thousand variable stars in Terzan 5 and Liller 1 with JWST
Kevin B. Burdge, Ilaria Caiazzo, Malina M. Desai +18
The Bulge Fossil Fragments Terzan 5 and Liller 1 host some of the densest stellar environments in the Galaxy, yet their variable star populations have remained largely unexplored d…
Stellar companions sculpt hot Jupiter formation and spin-orbit evolution
Cheyanne Shariat, Kareem El-Badry, Songhu Wang +4
Stellar companions can drive hot-Jupiter (HJ) migration and spin-orbit misalignment, but their role in HJ formation remains uncertain. We construct a homogeneous census of resolved…
Calibration of the Next Generation Palomar Spectrograph as a Stellar Speedometer
Pranav Nagarajan, Kareem El-Badry
We calibrate the Next Generation Palomar Spectrograph (NGPS) for precision stellar radial-velocity (RV) measurements using repeated observations of 24 Gaia-ESO RV standards spannin…
A survey of ultra-compact high-state AM CVn binaries with ZTF and Gaia: New discoveries and observational constraints on Galactic space density
Ilkham Galiullin, Antonio C. Rodriguez, Kareem El-Badry +9
Ultra-compact AM CVn binaries in the high-state of stable mass transfer () are expected to be among the loudest persistent sources for upcomin…
Lithium as a Signpost for Compact Object Binary Candidates in the LAMOST Medium Resolution Survey
Yang Shen, Joshua D. Simon, Kareem El-Badry +1
Binary systems with black hole or neutron star companions are often associated with lithium enhancement. Gaia NS1, a recently discovered neutron-star binary with a lithium-enhanced…
Population demographics of post-interaction WDMS binaries: From common envelope evolution to stable mass transfer
Natsuko Yamaguchi, Kareem El-Badry, Cheyanne Shariat
Close white dwarf (WD) + main-sequence (MS) binaries are end products of mass transfer (MT) that occurred prior to WD formation, making their population demographics a powerful pro…
A systematic survey for hypervelocity runaways from thermonuclear supernovae
Kareem El-Badry, Klaus Werner, Ken J. Shen +16
The explosion of a white dwarf (WD) in a close binary can launch a surviving runaway star at velocities of . Such runaways provide a direct probe of…
The Contribution of Disrupted Dense Star Clusters to Gaia's Compact Object Binaries
Aryanna Schiebelbein-Zwack, Claire S. Ye, Marta Reina-Campos +3
We present the first model of the Milky Way's detectable compact object--luminous star binary population from disrupted dense star clusters. We bridge large-scale cosmological star…
Searching for the Third Wheel: High-Contrast Imaging Constraints on Tertiaries to Black Hole and Neutron Star Binaries
Pranav Nagarajan, Kareem El-Badry, Aniket Sanghi
Black holes (BHs) and neutron stars (NSs) with low-mass stellar companions challenge traditional isolated binary evolution models, motivating hierarchical triple evolution as a pro…
Probing the IMF in the Early Universe -- Direct measurements in the Boötes I UFD with JWST/NIRCam
Keyi Ding, Mario Gennaro, Roberto J. Avila +20
The dependence of the stellar initial mass function (IMF) on star-formation environment, particularly at low metallicities and high redshifts, remains poorly constrained. Ultra-fai…
Detection of a weak magnetic field in the Balmer emission line white dwarf WDJ1653-1001
Abbigail Elms, Stefano Bagnulo, Pier-Emmanuel Tremblay +8
The small DAHe and DAe spectral classes comprise isolated, hydrogen-dominated atmosphere white dwarfs that exhibit variable photometric flux and Balmer line emission. These mysteri…
Gaia astrometry disfavors a binary origin for long secondary periods
Cheyanne Shariat, Kareem El-Badry, Morgan MacLeod +1
Approximately one-third of luminous pulsating red giant stars exhibit long secondary periods (LSPs): stable photometric variability with periods of several months to years in addit…
White dwarf + M dwarf Detached Binaries in Long Period Radio Transients: Observed Binary Parameters, Evolution, and Population Constraints
Antonio C. Rodriguez, Kareem El-Badry, Iris de Ruiter +4
Long period radio transients (LPTs) are the slowest radio-pulsing sources ever found, with the current population spanning periods of seven minutes to over six hours. Two of the th…
Deep Adaptive Optics Imaging Rules Out a Helium Star Companion to PSR J1928+1815
Pranav Nagarajan, Kareem El-Badry, Jim Fuller +2
PSR J1928+1815 is a 10.55 ms millisecond pulsar in a 3.6 hr orbit with a massive (-) companion that produces extended radio eclipses. The companion, proposed t…
Stars stably accreting from substellar objects
Aaron Householder, Kaitlyn Shin, Kevin B. Burdge +11
Substellar objects such as brown dwarfs and planets are generally expected to remain detached from their main-sequence host stars unless orbital decay or stellar expansion brings t…
Thermally inflated accretors in post-mass transfer binaries: Abell 35 and its class revisited
Soumyadeep Bhattacharjee, Kareem El-Badry, Jim Fuller +2
A small but growing class of binaries containing hot () white dwarfs (WDs) and rapidly rotating, apparently subgiant companions -- including the proto…
Radial Velocity Orbital Solutions for Candidate Black Hole and Neutron Star Binary Systems in the Gaia Data Release 3 Catalog
Joshua D. Simon, Casey Y. Lam, Kareem El-Badry +8
We present spectroscopic followup observations of binary systems from the Gaia Data Release 3 (DR3) binary catalog that were selected to have large enough mass functions for their…
A Path to an All-Sky Survey with Roman
Jiwon Jesse Han, Anirudh Chiti, Kai-Feng Chen +93
A deep, space-based, all-sky near-infrared survey carried out with the Nancy Grace Roman Space Telescope would constitute a foundational astronomical infrastructure for decades to…