Search Publications
Ion Charge States in a Time-Dependent Wave-Turbulence-Driven Model of the Solar Wind
Raymond, John; Velli, Marco; Downs, Cooper +4 more
Ion fractional charge states, measured in situ in the heliosphere, depend on the properties of the plasma in the inner corona. As the ions travel outward in the solar wind and the electron density drops, the charge states remain essentially unaltered or "frozen in". Thus they can provide a powerful constraint on heating models of the corona and ac…
K2-287 b: An Eccentric Warm Saturn Transiting a G-dwarf
Henning, Thomas; Jordán, Andrés; Espinoza, Néstor +23 more
We report the discovery of K2-287b, a Saturn mass planet orbiting a G-dwarf with a period of P ≈ 15 days. First uncovered as a candidate using K2 campaign 15 data, follow-up photometry and spectroscopy were used to determine a mass {M}{{P}}=0.317+/- 0.026 {M}{{J}}, radius {R}{{P}}=0.833+/- 0.013 {R}{{J}}…
Rediscovering the tidal tails of NGC 288 with Gaia DR2
Carlberg, Raymond; Hunt, Jason A. S.; Webb, Jeremy J. +2 more
NGC 288 is a Galactic globular cluster having observed extra-tidal structure, without confirmed tidal tails. Gaia DR2 provides photometric and astrometric data for many of the stars in NGC 288 and its extra-tidal structure. To compare with the Gaia data, we simulate a N-body model of a star cluster with the same orbit as NGC 288 in a Milky Way pot…
Effect of radiative heat transfer in porous comet nuclei: case study of 67P/Churyumov-Gerasimenko
Shi, Xian; Blum, Jürgen; Gundlach, Bastian +2 more
Context. Radiative heat transfer occurs in a porous medium, such as regolith on planetary bodies. Radiation enhances the efficiency of heat transport through the subsurface, effecting a strong temperature dependence of thermal conductivity. However, this effect has been omitted in many studies of comet 67P/Churyumov-Gerasimenko (67P).
Aims: W…
Deep ALMA search for CO gas in the HD 95086 debris disc
MacGregor, Meredith A.; Hughes, A. Meredith; Wilner, David J. +7 more
One of the defining properties of debris discs compared to protoplanetary discs used to be their lack of gas, yet small amounts of gas have been found around an increasing number of debris discs in recent years. These debris discs found to have gas tend to be both young and bright. In this paper, we conduct a deep search for CO gas in the system H…
High-resolution Extinction Map in the Direction of the Bulge Globular Cluster NGC 6440
Pallanca, Cristina; Ferraro, Francesco R.; Lanzoni, Barbara +3 more
We used optical images acquired with the UVIS channel of the Wide Field Camera 3 on board the Hubble Space Telescope to construct the first high-resolution extinction map in the direction of NGC 6440, a globular cluster located in the bulge of our Galaxy. The map has a spatial resolution of 0.″5 over a rectangular region of about 160″ × 240″ aroun…
On the Relation Between Transition Region Network Jets and Coronal Plumes
Fu, Hui; Li, Bo; Xia, Lidong +5 more
Both coronal plumes and network jets are rooted in network lanes. The relationship between the two, however, has yet to be addressed. For this purpose, we perform an observational analysis using images acquired on 2015 December 4 with the Atmospheric Imaging Assembly (AIA) 171 Å passband to follow the evolution of coronal plumes, the observations …
An X-Ray + Radio Search for Massive Black Holes in Blue Compact Dwarf Galaxies
Reines, Amy E.; Latimer, Lilikoi J.; Plotkin, Richard M. +2 more
Nearby blue compact dwarf (BCD) galaxies are arguably our best local analogs of galaxies in the earlier universe that may host relics of black hole (BH) seeds. Here we present high-resolution Chandra X-ray Observatory and Karl G. Jansky Very Large Array observations of five nearby BCDs with stellar masses of less than the Small Magellanic Cloud (M…
Dusty disk winds at the sublimation rim of the highly inclined, low mass young stellar object SU Aurigae
Monnier, John D.; Kraus, Stefan; Baron, Fabien +11 more
Context. T Tauri stars are low-mass young stars whose disks provide the setting for planet formation. Despite this, their structure is poorly understood. We present new infrared interferometric observations of the SU Aurigae circumstellar environment that offer resolution that is three times higher and a better baseline position angle coverage tha…
Eigenfunctions of Galactic phase space spirals from dynamic mode decomposition
Widrow, Lawrence M.; Darling, Keir
We investigate the spatiotemporal structure of simulations of the homogeneous slab and isothermal plane models for the vertical motion in the Galactic disc. We use dynamic mode decomposition (DMD) to compute eigenfunctions of the simulated distribution functions for both models, referred to as DMD modes. In the case of the homogeneous slab, we com…