Search Publications
Missions
Journals
Publication Years
Evidence of Photoevaporation and Spatial Variation of Grain Sizes in the Orion 114-426 Protoplanetary Disk
Ricci, L.; Miotello, Anna; Robberto, Massimo +1 more
Deep Hubble Space Telescope broadband images taken with Advanced Camera for Surveys (ACS) and WFPC2 of the giant (~1000 AU diameter) dark silhouette proplyd 114-426 in the Orion Nebula show that this system is tilted, asymmetric, warped, and photoevaporated. The exquisite angular resolution of ACS allows us to map the distribution of dust grains a…
Numerical simulation of the effects of a solar energetic particle event on the ionosphere of Mars
Simon Wedlund, C.; Haider, S. A.; Withers, Paul +5 more
We investigate the ionospheric effects of a solar energetic particle (SEP) event at Mars, specifically the 29 September 1989 event. We use its energy spectrum and a steady state ionospheric model to simulate vertical profiles of ion and electron densities. The ionospheric response to this large event would have been readily observable. It caused e…
Revealing a ring-like cluster complex in a tidal tail of the starburst galaxy NGC 2146
Bastian, N.; Larsen, S. S.; Gallagher, J. S. +9 more
We report the discovery of a ring-like cluster complex in the starburst galaxy NGC 2146. The Ruby Ring, so named due to its appearance, shows a clear ring-like distribution of star clusters around a central object. It is located in one of the tidal streams that surround the galaxy. NGC 2146 is part of the Snapshot Hubble U-band Cluster Survey (SHU…
The formation of small cones in Isidis Planitia, Mars through mobilization of pyroclastic surge deposits
Ghent, Rebecca R.; Anderson, Steven W.; Pithawala, Taronish M.
We investigate the distinctive distribution and pattern of subkilometer-sized cones in Isidis Planitia, and their relationship to the material that fills the basin. We observe that: (1) the cones show uniform size, spacing, and morphology across the entire basin; (2) they have large central depressions (relative to cone basal diameters) that are g…
Secular Changes in Eta Carinae's Wind 1998-2011
Walter, Frederick M.; Humphreys, Roberta M.; Davidson, Kris +4 more
Stellar wind-emission features in the spectrum of eta Carinae have decreased by factors of 1.5-3 relative to the continuum within the last 10 years. We investigate a large data set from several instruments (STIS, GMOS, UVES) obtained between 1998 and 2011 and analyze the progression of spectral changes in direct view of the star, in the reflected …
HST/WFPC2 imaging of the dwarf satellites And XI and And XIII: horizontal branch morphology and RR Lyraes
Sarajedini, A.; Yang, S. -C.
We present a study of the stellar populations in two faint M31 dwarf satellites, Andromeda XI and Andromeda XIII. Using archival images from the Wide Field Planetary Camera 2 onboard the Hubble Space Telescope, we characterize the horizontal branch (HB) morphologies and the RR Lyrae (RRL) populations of these two faint dwarf satellites. Our new te…
Phase space structure of the electron diffusion region in reconnection with weak guide fields
Egedal, J.; Daughton, W.; Ng, J. +1 more
Kinetic simulations of magnetic reconnection provide detailed information about the electric and magnetic structure throughout the simulation domain, as well as high resolution profiles of the essential fluid parameters including the electron and ion densities, flows, and pressure tensors. However, the electron distribution function, f(v), within …
Infrared excess around nearby red giant branch stars and Reimers law
Groenewegen, M. A. T.
Context. Mass loss is one of the fundamental properties of asymptotic giant branch (AGB) stars, but for stars with initial masses below ~1 M⊙, the mass loss on the first red giant branch (RGB) actually dominates mass loss on the AGB. Nevertheless, mass loss on the RGB is still often parameterised by a simple Reimers law in stellar evolu…
Investigation of air temperature on the nightside of Venus derived from VIRTIS-H on board Venus-Express
Drossart, P.; Piccioni, G.; Lebonnois, S. +3 more
We present the spatial distribution of air temperature on Venus' night side, as observed by the high spectral resolution channel of VIRTIS (Visible and Infrared Thermal Imaging Spectrometer), or VIRTIS-H, on board the ESA mission Venus Express. The present work extends the investigation of the average thermal fields in the northern hemisphere of V…
Globules and pillars seen in the [CII] 158 µm line with SOFIA
Hill, T.; Lebouteiller, V.; Cormier, D. +22 more
Molecular globules and pillars are spectacular features, found only in the interface region between a molecular cloud and an H II-region. Impacting far-ultraviolet (FUV) radiation creates photon-dominated regions (PDRs) on their surfaces that can be traced by typical cooling lines. With the GREAT receiver onboard SOFIA we mapped and spectrally res…