Search Publications
A Fast Model for the Reconstruction of Spectral Solar Irradiance in the Near- and Mid-Ultraviolet
Charbonneau, P.; Crouch, A. D.; Bolduc, C. +2 more
We present a model for the reconstruction of spectral solar irradiance between 200 and 400 nm. This model is an extension of the total solar irradiance (TSI) model of Crouch et al. (Astrophys. J.677, 723, 2008) which is based on a data-driven Monte Carlo simulation of sunspot emergence, fragmentation, and erosion. The resulting time-evolving daily…
Optimizing Automated Classification of Variable Stars in New Synoptic Surveys
Bloom, Joshua S.; Richards, Joseph W.; Long, James P. +2 more
Efficient and automated classification of periodic variable stars is becoming increasingly important as the scale of astronomical surveys grows. Several recent articles have used methods from machine learning and statistics to construct classifiers on databases of labeled, multi-epoch sources with the intention of using these classifiers to automa…
Evolution of massive galaxy structural properties and sizes via star formation in the GOODS NICMOS Survey
Conselice, Christopher J.; Hartley, William G.; Mortlock, Alice +2 more
We present a study of the resolved star-forming properties of a sample of distant massive (M > 1011 M⊙) galaxies in the GOODS NICMOS Survey (GNS), based on deep Hubble Space Telescope imaging from the GOODS North and South fields. We derive dust corrected ultraviolet star formation rates (SFRs) as a function of radius for …
An Empirical Measure of the Rate of White Dwarf Cooling in 47 Tucanae
Tremblay, P. -E.; Stetson, P. B.; Bergeron, P. +8 more
We present an empirical determination of the white dwarf cooling sequence in the globular cluster 47 Tucanae. Using spectral models, we determine temperatures for 887 objects from Wide Field Camera 3 data, as well as 292 objects from data taken with the Advanced Camera for Surveys. We make the assumption that the rate of white dwarf formation in t…
Herschel/HIFI observation of highly excited rotational lines of HNC toward IRC +10 216
Cernicharo, J.; Daniel, F.; Müller, H. S. P. +6 more
We report the detection in emission of various highly excited rotational transitions of HNC (J = 6-5 through J = 12-11) toward the carbon-star envelope IRC +10 216 using the HIFI instrument on-board the Herschel Space Observatory. Observations of the J = 1-0 and J = 3-2 lines of HNC with the IRAM 30-m telescope are also presented. The lines observ…
Saturn's auroral/polar H3+ infrared emission: The effect of solar wind compression
Dougherty, Michele K.; Bunce, Emma J.; Melin, Henrik +6 more
Previous investigations into Saturn's aurora have shown that they are strongly controlled by the solar wind. Here, for the first time, we use a combination of ground-based infrared observations of the aurora and in situ measurements of the magnetosphere in order to better understand this association. We show that large-scale variability in both th…
First Observation in the South of Titan's Far-infrared 220 cm-1 Cloud
Teanby, N. A.; Calcutt, S. B.; de Kok, R. +15 more
An emission feature at 220 cm-1 which has been attributed to a cloud of condensed material in Titan's winter stratosphere has been seen for the first time in the south. This feature had previously been found only at high northern latitudes during northern winter and spring. The material emitting at 220 cm-1, as yet unidentifi…
A newly discovered impact crater in Titan's Senkyo: Cassini VIMS observations and comparison with other impact features
Le Mouélic, S.; Sotin, C.; Brown, R. H. +7 more
Senkyo is an equatorial plain on Titan filled with dunes and surrounded by hummocky plateaus. During the Titan targeted flyby T61 on August 25, 2009, the Cassini Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft observed a circular feature, centered at 5.4° N and 341°W, that superimposes the dune fields and a bright pl…
An alternative origin for debris rings of planetesimals
Nayakshin, Sergei; Cha, Seung-Hoon
Core accretion (CA), the most widely accepted scenario for planet formation, postulates existence of ∼ km-sized solid bodies, called planetesimals, arranged in a razor-thin disc in the earliest phases of planet formation. These objects coagulate by collisions, eventually building planetary cores. In the tidal downsizing (TD) hypothesis, an alterna…
Possible sources for methane and C2-C5 organics in the plume of Enceladus
McKay, C. P.; Khare, B. N.; Amin, R. +2 more
We consider six possible sources of CH4 and other lowmass (C2-C5) organics in the plume of Enceladus: three of these sources represent initial endowments of organics: cometary organics, Titan-like tholin, and the Fisher-Tropsch type reactions in the gases from which Enceladus formed. The other three sources represe…