Search Publications
Saturn's magnetospheric interaction with Titan as defined by Cassini encounters T9 and T18: New results
Coates, A. J.; Johnson, R. E.; Wahlund, J. -E. +8 more
We present new results of Cassini's T9 flyby with complementary observations from T18. Based on Cassini plasma spectrometer (CAPS) and Cassini magnetometer (MAG), compositional evidence shows the upstream flow for both T9 and T18 appears composed of light ions (H + and H 2+), with external pressures ∼30 times lower…
Erratum: "Determining Titan's Spin State from Cassini Radar Images"
Iess, Luciano; Cassini RADAR Team; Stiles, Bryan W. +12 more
We previously reported an initial determination of Titan's rotational state from fits to overlapping radar images. We have since discovered a coding error in software used to make these fits, which led to systematic offsets of 1-2 km in recovered positions. While our principal results remain qualitatively unchanged, with this error corrected, the …
Pre-main-sequence Turn-On as a Chronometer for Young Clusters: NGC 346 as a Benchmark
Prada Moroni, P. G.; Degl'Innocenti, S.; Cignoni, M. +4 more
We present a novel approach to deriving the age of very young star clusters, by using the Turn-On (TOn). The TOn is the point in the color-magnitude diagram (CMD) where the pre-main sequence (PMS) joins the main sequence (MS). In the MS luminosity function (LF) of the cluster, the TOn is identified as a peak followed by a dip. We propose that by c…
Star formation in the outer filaments of NGC 1275
Fabian, A. C.; Gallagher, J. S.; Conselice, C. J. +5 more
We present photometry of the outer star clusters in NGC 1275, the brightest galaxy in the Perseus cluster. The observations were taken using the Hubble Space Telescope Advanced Camera for Surveys. We focus on two stellar regions in the south and south-east, far from the nucleus of the low-velocity system (~22kpc). These regions of extended star fo…
Evolution of low-altitude and ring current ENA emissions from a moderate magnetospheric storm: Continuous and simultaneous TWINS observations
Roelof, E.; McComas, D. J.; Brandt, P. C. +6 more
The moderate storm of 22 July 2009 is the largest measured during the extended solar minimum between December 2006 and March 2010. We present observations of this storm made by the two wide-angle imaging neutral-atom spectrometers (TWINS) mission. The TWINS mission measures energetic neutral atoms (ENAs) using sensors mounted on two separate space…
Jupiter After the 2009 Impact: Hubble Space Telescope Imaging of the Impact-generated Debris and its Temporal Evolution
Hueso, R.; Sánchez-Lavega, A.; Fletcher, L. N. +9 more
We report Hubble Space Telescope images of Jupiter during the aftermath of an impact by an unknown object in 2009 July. The 2009 impact-created debris field evolved more slowly than those created in 1994 by the collision of the tidally disrupted comet D/Shoemaker-Levy 9 (SL9). The slower evolution, in conjunction with the isolated nature of this s…
Estimation of the escape of photoelectrons from Mars in 2004 liberated by the ionization of carbon dioxide and atomic oxygen
Coates, A. J.; Fedorov, A.; Barabash, S. +8 more
Photoelectron peaks in the atmosphere of Mars caused by the ionization of carbon dioxide and atomic oxygen by solar 30.4 nm photons have been observed by the Electron Spectrometer (ELS), a component of the Mars Express (MEx) Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) experiment. Ionization mostly occurs at the Mars exobase with the m…
Fine-structure infrared lines from the Cassiopeia A knots
Sunyaev, R. A.; Docenko, D.
Aims: Archival observations of infrared fine-structure lines of the young Galactic supernova remnant Cassiopeia A allow us to test existing models and determine the physical parameters of various regions of the fast-moving knots, which are metal-dominated clouds of material ejected by the supernova explosion.
Methods: The fluxes of far-i…
First detection of the methylidyne cation (CH+) fundamental rotational line with the Herschel/SPIRE FTS
Miville-Deschênes, M. -A.; Boulanger, F.; Abergel, A. +42 more
Aims: To follow the species chemistry arising in diverse sources of the Galaxy with Herschel.
Methods: SPIRE FTS sparse sampled maps of the Orion bar & compact HII regions G29.96-0.02 and G32.80+0.19 have been analyzed.
Results: Beyond the wealth of atomic and molecular lines detected in the high-resolution spectra obtained with…
A Late Amazonian alteration layer related to local volcanism on Mars
Mangold, N.; Le Mouélic, S.; Mustard, J. F. +7 more
Hydrated minerals on Mars are most commonly found in ancient terrains dating to the first billion years of the planet's evolution. Here we discuss the identification of a hydrated light-toned rock unit present in one Chasma of the Noctis Labyrinthus region. Stratigraphy and topography show that this alteration layer is part of a thin unit that dra…