Search Publications
Rotating Motions and Modeling of the Erupting Solar Polar-crown Prominence on 2010 December 6
van Ballegooijen, Adriaan; Su, Yingna
A large polar-crown prominence composed of different segments spanning nearly the entire solar disk erupted on 2010 December 6. Prior to the eruption, the filament in the active region part split into two layers: a lower layer and an elevated layer. The eruption occurs in several episodes. Around 14:12 UT, the lower layer of the active region fila…
Gas-phase Sequestration of Noble Gases in the Protosolar Nebula: Possible Consequences on the Outer Solar System Composition
Mousis, O.; Ali-Dib, M.; Pauzat, F. +2 more
We address the problem of the sequestration of Ar, Kr, and Xe by H_3^+ in the gas-phase conditions encountered during the cooling of protoplanetary disks when H_3^+ is competing with other species present in the same environment. Using high-level ab initio simulations, we try to quantify other sequestration possibilities involving He, H_5^+, H
Plasma Heating in a Post Eruption Current Sheet: A Case Study Based on Ultraviolet, Soft, and Hard X-Ray Data
Krucker, Säm; Bemporad, A.; Susino, R.
Off-limb observations of the solar corona after coronal mass ejections (CMEs) often show strong, compact, and persistent UV sources behind the eruption. They are primarily observed by the SOHO/UVCS instrument in the "hot" [Fe XVIII] λ974 line and are usually interpreted as a signature of plasma heating due to magnetic reconnection in the post-CME …
The Metallicity Dependence of the Cepheid P - L Relation in M101
Madore, Barry F.; Freedman, Wendy L.; Mager, Violet A.
The impact of metallicity on the Cepheid period-luminosity (P - L) relation is investigated using Hubble Space Telescope Advanced Camera for Surveys V and I images of M101. Variations in the reddening-free Wesenheit parameter (W), which is employed as a proxy for luminosity, are examined as a function of the radial distance from the center of M101…
Supernova Remnant Kes 17: An Efficient Cosmic Ray Accelerator inside a Molecular Cloud
Gelfand, Joseph D.; Temim, Tea; Hughes, John P. +3 more
The supernova remnant Kes 17 (SNR G304.6+0.1) is one of a few but growing number of remnants detected across the electromagnetic spectrum. In this paper, we analyze recent radio, X-ray, and γ-ray observations of this object, determining that efficient cosmic ray acceleration is required to explain its broadband non-thermal spectrum. These observat…
A Transmission Spectrum of Titan's North Polar Atmosphere from a Specular Reflection of the Sun
Nicholson, Philip D.; Sotin, Christophe; Barnes, Jason W. +9 more
Cassini/VIMS T85 observations of a solar specular reflection off of Kivu Lacus (87.°4N 241.°1E) provide an empirical transmission spectrum of Titan's atmosphere. Because this observation was acquired from short range (33,000 km), its intensity makes it visible within the 2.0, 2.7, and 2.8 µm atmospheric windows in addition to the 5 µm …
Low-frequency Observations of Drifting, Non-thermal Continuum Radio Emission Associated with the Solar Coronal Mass Ejections
Ramesh, R.; Kathiravan, C.; Wang, T. J. +3 more
Low-frequency (80 MHz) imaging and spectral (≈85-20 MHz) observations of moving type IV radio bursts associated with coronal mass ejections (CMEs) from the Sun on three different days are reported. The estimated drift speed of the bursts is in the range ≈150-500 km s-1. We find that all three bursts are most likely due to second harmoni…
Hubble Space Telescope Imaging of the Binary Nucleus of the Planetary Nebula EGB 6
Bond, Howard E.; Gianninas, A.; Ciardullo, Robin +4 more
EGB 6 is an ancient, low-surface-brightness planetary nebula. The central star, also cataloged as PG 0950+139, is a very hot DAOZ white dwarf (WD) with an apparent M dwarf companion, unresolved from the ground but detected initially through excesses in the JHK bands. Its kinematics indicates membership in the Galactic disk population. Inside of EG…
Blue Straggler Evolution Caught in the Act in the Large Magellanic Cloud Globular Cluster Hodge 11
Deng, Licai; de Grijs, Richard; Li, Chengyuan +1 more
High-resolution Hubble Space Telescope imaging observations show that the radial distribution of the field-decontaminated sample of 162 "blue straggler" stars (BSs) in the 11.7^{+0.2}_{-0.1} Gyr old Large Magellanic Cloud cluster Hodge 11 exhibits a clear bimodality. In combination with their distinct loci in color-magnitude space, this offers new…
The Paα Luminosity Function of H II Regions in Nearby Galaxies from HST/NICMOS
Calzetti, Daniela; Schinnerer, Eva; Egusa, Fumi +5 more
The H II region luminosity function (LF) is an important tool for deriving the birthrates and mass distribution of OB associations and is an excellent tracer of the newly formed massive stars and associations. To date, extensive work (predominantly in Hα) has been done from the ground, which is hindered by dust extinction and the severe blending o…