Search Publications
Transmission Spectroscopy for the Warm Sub-Neptune HD 3167c: Evidence for Molecular Absorption and a Possible High-metallicity Atmosphere
Gorjian, Varoujan; Fortney, Jonathan J.; Mikal-Evans, Thomas +26 more
We present a transmission spectrum for the warm (500-600 K) sub-Neptune HD 3167c obtained using the Hubble Space Telescope Wide Field Camera 3 infrared spectrograph. We combine these data, which span the 1.125-1.643 µm wavelength range, with broadband transit measurements made using Kepler/K2 (0.6-0.9 µm) and Spitzer/IRAC (4-5 µm…
Massive Compact Disks around FU Orionis-type Young Eruptive Stars Revealed by ALMA
Kudo, T.; Liu, H. B.; Ábrahám, P. +14 more
The FU Orionis-type objects (FUors) are low-mass pre-main-sequence stars undergoing a temporary but significant increase of mass accretion rate from the circumstellar disk onto the protostar. It is not yet clear what triggers the accretion bursts and whether the disks of FUors are in any way different from the disks of nonbursting young stellar ob…
Multi-instrumental view of magnetic fields and activity of ɛ Eridani with SPIRou, NARVAL, and TESS
Donati, J. -F.; Petit, P.; Vidotto, A. A. +6 more
Aims: We report on observations of the active K2 dwarf ɛ Eridani based on contemporaneous SPIRou, NARVAL and TESS data obtained over two months in late 2018, when the activity of the star was reported to be in a non-cyclic phase.
Methods: Near-infrared (NIR) spectropolarimetry was obtained using SPIRou over four nights in late September,…
On the Correlation between Hot Jupiters and Stellar Clustering: High-eccentricity Migration Induced by Stellar Flybys
Rodet, Laetitia; Lai, Dong; Su, Yubo
A recent observational study suggests that the occurrence of hot Jupiters (HJs) around solar-type stars is correlated with stellar clustering. We study a new scenario for HJ formation, called "Flyby Induced High-e Migration," that may help explain this correlation. In this scenario, stellar flybys excite the eccentricity and inclination of an oute…
The Pristine survey XIII: uncovering the very metal-poor tail of the thin disc
Sestito, Federico; Navarro, Julio F.; Malhan, Khyati +9 more
We evaluate the rotational velocity of stars observed by the Pristine survey towards the Galactic anticentre spanning a wide range of metallicities from the extremely metal-poor regime ([Fe/H] < -3) to nearly solar metallicity. In the Galactic anticentre direction, the rotational velocity (Vϕ) is similar to the tangential velocity in…
Quantifying Non-parametric Structure of High-redshift Galaxies with Deep Learning
Bamford, S. P.; Conselice, C. J.; Ferrari, F. +2 more
At high redshift, due to both observational limitations and the variety of galaxy morphologies in the early universe, measuring galaxy structure can be challenging. Non-parametric measurements such as the CAS system have thus become an important tool due to both their model-independent nature and their utility as a straightforward computational pr…
TOI-2109: An Ultrahot Gas Giant on a 16 hr Orbit
Lester, Kathryn V.; Bieryla, Allyson; Latham, David W. +56 more
We report the discovery of an ultrahot Jupiter with an extremely short orbital period of 0.67247414 ± 0.00000028 days (~16 hr). The 1.347 ± 0.047 R Jup planet, initially identified by the Transiting Exoplanet Survey Satellite (TESS) mission, orbits TOI-2109 (TIC 392476080)-a T eff ~ 6500 K F-type star with a mass of 1.447 ± 0…
CME Magnetic Structure and IMF Preconditioning Affecting SEP Transport
Lowrance, Patrick J.; Möstl, Christian; Guo, Jingnan +15 more
Coronal mass ejections (CMEs) and solar energetic particles (SEPs) are two phenomena that can cause severe space weather effects throughout the heliosphere. The evolution of CMEs, especially in terms of their magnetic structure, and the configuration of the interplanetary magnetic field (IMF) that influences the transport of SEPs are currently are…
A Census of Blue Stragglers in Gaia DR2 Open Clusters as a Test of Population Synthesis and Mass Transfer Physics
Leiner, Emily M.; Geller, Aaron
We use photometry and proper motions from Gaia DR2 to determine the blue straggler star (BSS) populations of 16 old (1-10 Gyr), nearby (d < 3500 pc) open clusters. We find that the fractional number of BSS compared to red giant branch stars increases with age, starting near zero at 1 Gyr and flattening to ∼0.35 by 4 Gyr. Fitting stellar evoluti…
Mass calibration of distant SPT galaxy clusters through expanded weak-lensing follow-up observations with HST, VLT, & Gemini-South
Schrabback, T.; Schirmer, M.; Sommer, M. +18 more
Expanding from previous work, we present weak-lensing (WL) measurements for a total sample of 30 distant (zmedian = 0.93) massive galaxy clusters from the South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) Survey, measuring galaxy shapes in Hubble Space Telescope (HST) Advanced Camera for Surveys images. We remove cluster members and pref…