Search Publications
Near-infrared Imaging of a Spiral in the CQ Tau Disk
Currie, Thayne; Dong, Ruobing; Kwon, Jungmi +28 more
We present L'-band Keck/NIRC2 imaging and H-band Subaru/AO188+HiCIAO polarimetric observations of the CQ Tau disk with a new spiral arm. Apart from the spiral feature, our observations could not detect any companion candidates. We traced the spiral feature from the r2-scaled High-Contrast Coronographic Imager for Adaptive Optics (HiCIAO…
Interstellar comet 2I/Borisov exhibits a structure similar to native Solar system comets
Bedin, L. R.; Ochner, P.; Manzini, F. +1 more
We processed images taken with the Hubble Space Telescope(HST) to investigate any morphological features in the inner coma suggestive of a peculiar activity on the nucleus of the interstellar comet 2I/Borisov. The coma shows an evident elongation, in the position angle (PA) ∼0-180○ direction, which appears related to the presence of a j…
The extreme colliding-wind system Apep: resolved imagery of the central binary and dust plume in the infrared
Callingham, J. R.; Crowther, P. A.; Marcote, B. +6 more
The recent discovery of a spectacular dust plume in the system 2XMM J160050.7-514245 (referred to as 'Apep') suggested a physical origin in a colliding-wind binary by way of the 'Pinwheel' mechanism. Observational data pointed to a hierarchical triple-star system, however, several extreme and unexpected physical properties seem to defy the establi…
The search for disks or planetary objects around directly imaged companions: a candidate around DH Tauri B
Ertel, S.; Henning, T.; Brandner, W. +45 more
Context. In recent decades, thousands of substellar companions have been discovered with both indirect and direct methods of detection. While the majority of the sample is populated by objects discovered using radial velocity and transit techniques, an increasing number have been directly imaged. These planets and brown dwarfs are extraordinary so…
The Pre-He White Dwarf in the Post-mass Transfer Binary EL CVn
Gies, Douglas R.; Lester, Kathryn V.; Wang, Luqian +8 more
EL CVn is the prototype of a class of eclipsing binaries that consist of an A- or F-type main-sequence star and a hot, low-mass, pre-He white dwarf (pre-He WD), the stripped down remains of the former mass donor. Here we present the first direct detection and characterization of the spectrum of the pre-He WD in EL CVn that was made possible throug…
Global analysis of the TRAPPIST Ultra-Cool Dwarf Transit Survey
Queloz, D.; Delrez, L.; Gillon, M. +10 more
We conducted a global analysis of the TRAPPIST Ultra-Cool Dwarf Transit Survey - a prototype of the SPECULOOS transit search conducted with the TRAPPIST-South robotic telescope in Chile from 2011 to 2017 - to estimate the occurrence rate of close-in planets such as TRAPPIST-1b orbiting ultra-cool dwarfs. For this purpose, the photometric data of 4…
Lithium-rotation connection in the newly discovered young stellar stream Psc-Eri (Meingast 1)
Bayo, A.; Bouy, H.; Bouvier, J. +4 more
Context. As a fragile element, lithium is a sensitive probe of physical processes occurring in stellar interiors.
Aims: We aim to investigate the relationship between lithium abundance and rotation rate in low-mass members of the newly discovered 125 Myr-old Psc-Eri stellar stream.
Methods: We obtained high-resolution optical spectra and…
Foreshock Bubbles at Venus: Hybrid Simulations and VEX Observations
Omidi, N.; Collinson, G.; Sibeck, D.
In the absence of a global magnetic field at Venus, its ionosphere is the obstacle to the flow of the solar wind resulting in the formation of a smaller bow shock and foreshock. Spacecraft observations and global hybrid (kinetic ions, fluid electrons) simulations have demonstrated that despite its smaller size, the foreshock at Venus has propertie…
New empirical constraints on the cosmological evolution of gas and stars in galaxies
Loeb, Abraham; Padmanabhan, Hamsa
We combine the latest observationally motivated constraints on stellar properties in dark matter haloes, along with data-driven predictions for the atomic (H I) and molecular (H2) gas evolution in galaxies, to derive empirical relationships between the build-up of galactic components and their evolution over cosmic time. At high redshif…
Embedding globular clusters in dark matter minihaloes solves the cusp-core and timing problems in the Fornax dwarf galaxy
Silk, Joseph; Boldrini, Pierre; Mohayaee, Roya
We use a fully GPU N-body code to demonstrate that dark matter (DM) minihaloes, as a new component of globular clusters (GCs), resolve both the timing and cusp-core problems in Fornax if the (five or six) GCs were recently accreted (≤3 Gyr ago) by Fornax. Under these assumptions, infall of these GCs does not occur and no star clusters form in the …