Search Publications
Constraints on the Occurrence and Distribution of 1-20 M Jup Companions to Stars at Separations of 5-5000 au from a Compilation of Direct Imaging Surveys
Gagné, Jonathan; Delorme, Philippe; Lafrenière, David +4 more
We present the first statistical analysis of exoplanet direct imaging surveys combining adaptive optics (AO) imaging at small separations with deep seeing-limited observations at large separations allowing us to study the entire orbital separation domain from 5 to 5000 au simultaneously. Our sample of 344 stars includes only confirmed members of n…
Accretion Kinematics in the T Tauri Binary TWA 3A: Evidence for Preferential Accretion onto the TWA 3A Primary
Johns-Krull, Christopher M.; Tofflemire, Benjamin M.; Mathieu, Robert D.
We present time-series, high-resolution optical spectroscopy of the eccentric T Tauri binary TWA 3A. Our analysis focuses on variability in the strength and structure of the accretion-tracing emission lines Hα and He I 5876 Å. We find emission line strengths to display the same orbital phase-dependent behavior found with time-series photometry, na…
From Scattered-light to Millimeter Emission: A Comprehensive View of the Gigayear-old System of HD 202628 and its Eccentric Debris Ring
Hughes, A. Meredith; Wilner, David J.; Stapelfeldt, Karl R. +13 more
We present here new observations of the eccentric debris ring surrounding the Gyr-old solar-type star HD 202628: at millimeter wavelengths with ALMA, at far-infrared wavelengths with Herschel, and in scattered light with the Hubble Space Telescope (HST). The ring inner edge is found to be consistent between ALMA and HST data. As radiation pressure…
Characterizing K2 Candidate Planetary Systems Orbiting Low-mass Stars. IV. Updated Properties for 86 Cool Dwarfs Observed during Campaigns 1-17
Vanderburg, Andrew; Schlieder, Joshua E.; Crepp, Justin R. +15 more
We present revised stellar properties for 172 K2 target stars that were identified as possible hosts of transiting planets during Campaigns 1-17. Using medium-resolution near-infrared spectra acquired with the NASA Infrared Telescope Facility/SpeX and Palomar/TripleSpec, we found that 86 of our targets were bona fide cool dwarfs, 74 were hotter dw…
Spitzer Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-rotating Low-mass Brown Dwarf
Helling, Christiane; Maoz, Dan; Tan, Thiam-Guan +69 more
The kinematics of isolated brown dwarfs in the Galaxy, beyond the solar neighborhood, is virtually unknown. Microlensing has the potential to probe this hidden population, as it can measure both the mass and five of the six phase-space coordinates (all except the radial velocity) even of a dark isolated lens. However, the measurements of both the …
The Mass-Activity Relationships in M and K Dwarfs. I. Stellar Parameters of Our Sample of M and K Dwarfs
Doyle, J. G.; Mullan, D. J.; Butler, C. J. +3 more
Empirical correlations between stellar parameters such as rotation or radius and magnetic activity diagnostics require estimates of the effective temperatures and the stellar radii. The aim of this study is to propose simple methods that can be applied to large samples of stars in order to derive estimates of the stellar parameters. Good empirical…
New Substellar Discoveries from Kepler and K2: Is There a Brown Dwarf Desert?
Latham, David W.; Carmichael, Theron W.; Vanderburg, Andrew M.
We present the discoveries of a brown dwarf (BD) and a low-mass star from the Kepler and K2 missions. The newly discovered BD is EPIC 212036875b and the low-mass star is KOI-607b. EPIC 212036875b has a mass of M b = 52.3 ± 1.9 M J, a radius of R b = 0.874 ± 0.017 R J, and orbits its host star in P = …
Ultra-bright CO and [C I] Emission in a Lensed z = 2.04 Submillimeter Galaxy with Extreme Molecular Gas Properties
Rebolo, R.; Krips, M.; Dannerbauer, H. +4 more
We report the very bright detection of cold molecular gas with the IRAM NOEMA interferometer of the strongly lensed source WISE J132934.18+224327.3 at z = 2.04, the so-called Cosmic Eyebrow. This source has a similar spectral energy distribution from optical-mid/IR to submillimeter/radio but significantly higher fluxes than the well-known lensed S…
Hubble Space Telescope Flux Calibration. I. STIS and CALSPEC
Bohlin, Ralph C.; Deustua, Susana E.; de Rosa, Gisella
The precision of absolute flux measurements is quantified for the Space Telescope Imaging Spectrograph (STIS), which is the most important contributor to the CALSPEC standards. With our goal of 1% absolute accuracy, the documentation of the Hubble Space Telescope/CALSPEC flux scale and its subpercent repeatability are of prime importance. While th…
Ruprecht 147: A Paradigm of Dissolving Star Cluster
Carraro, Giovanni; Seleznev, Anton F.; Montalto, Marco +1 more
We employed recent Gaia/DR2 data to investigate the dynamical status of the nearby (300 pc), old (2.5 Gyr) open cluster Ruprecht 147. We found prominent leading and trailing tails of stars along the cluster orbit, which demonstrates that Ruprecht 147 is losing stars at fast pace. Star counts indicate the cluster has a core radius of 33.3 arcmin an…