36 citations · 94 across the 45 of their papers we have counts for
45 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…
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…
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…
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…
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…
JWST observations of three long-period AM CVn binaries: detection of the donors and hints of magnetically truncated disks
Kareem El-Badry, Antonio C. Rodriguez, Matthew J. Green +1
We present JWST/NIRSpec high-cadence infrared spectroscopy of three long-period, eclipsing AM CVn binaries, Gaia14aae, SRGeJ0453, and ZTFJ1637. These systems have orbital periods o…
Testing models for fully and partially stripped low-mass stars with Gaia: Implications for hot subdwarfs, binary RR Lyrae, and black hole impostors
Pranav Nagarajan, Kareem El-Badry, Alexey Bobrick +4
When low-mass ( ) red giants lose their envelopes to a companion just before the helium flash, the resulting mass transfer can produce binaries hosting hot s…
An eclipsing 8.56 minute orbital period mass-transferring binary
Emma T. Chickles, Joheen Chakraborty, Kevin B. Burdge +34
We report the discovery of ATLAS J101342.5-451656.8 (hereafter ATLAS J1013-4516), an 8.56 minute orbital period mass transferring AM Canum Venaticorum binary with mean Gaia magnitu…
Chemical Signatures of AGB Mass Transfer in Gaia White Dwarf Companions
Natsuko Yamaguchi, Kareem El-Badry, Henrique Reggiani +2
We present a homogeneous abundance analysis of 160 main-sequence stars in astrometric white-dwarf + main-sequence (WD+MS) binaries with orbits from Gaia DR3. These systems have AU-…
Ultraviolet spectroscopy reveals a hot and luminous companion to the Be star+black hole candidate MWC 656
Johanna Müller-Horn, Varsha Ramachandran, Kareem El-Badry +11
The Galactic Be star binary MWC 656 was long considered the only known Be star+black hole (BH) system, making it a critical benchmark for models of massive binary evolution and for…
A global view of post-interaction white dwarf-main sequence binaries
Cheyanne Shariat, Kareem El-Badry
Common-envelope evolution (CEE) is among the most uncertain phases in binary evolution. To empirically constrain CEE, we construct a uniformly selected sample of eclipsing post--co…