Search Publications
Global Helioseismic Evidence for a Deeply Penetrating Solar Meridional Flow Consisting of Multiple Flow Cells
Roth, M.; Schad, A.; Timmer, J.
We use a novel global helioseismic analysis method to infer the meridional flow in the deep Solar interior. The method is based on the perturbation of eigenfunctions of Solar p modes due to meridional flow. We apply this method to time series obtained from Dopplergrams measured by the Michelson Doppler Imager aboard the Solar and Heliospheric Obse…
Enceladus: An Active Ice World in the Saturn System
Nimmo, Francis; Spencer, John R.
Enceladus, one of the mid-sized icy moons of Saturn, has an importance to planetary science far greater than its modest 504-km diameter would suggest. Intensive exploration of Enceladus by the Cassini Saturn orbiter has revealed that it is the only known icy world in the solar system with ongoing deep-seated geological activity. Active tectonic fr…
Macroclumping as solution of the discrepancy between Hα and P v mass loss diagnostics for O-type stars
Hamann, W. -R.; Oskinova, L. M.; Aret, A. +3 more
Context. Recent studies of O-type stars have demonstrated that discrepant mass-loss rates are obtained when different diagnostic methods are employed. Fitting the unsaturated UV resonance lines (e.g., P v) gives drastically lower values than obtained from the Hα emission. Wind inhomogeneity (so-called "clumping") may be the main cause of this disc…
Improved photometric calibration of the SNLS and the SDSS supernova surveys
Kessler, R.; Marriner, J.; Sako, M. +13 more
Context. We present a combined photometric calibration of the Supernova Legacy Survey (SNLS) and the SDSS supernova survey, which results from a joint effort of the SDSS and the SNLS collaborations.
Aims: Our primary motivation is to eventually sharpen cosmological constraints derived from type Ia supernova measurements by improving the accur…
Hubble Space Telescope detection of oxygen in the atmosphere of exoplanet HD 189733b
Ballester, G. E.; Ben-Jaffel, L.
Detecting heavy atoms in the inflated atmospheres of giant exoplanets that orbit close to their parent stars is a key factor for understanding their bulk composition, their evolution, and the processes that drive their expansion and interaction with the impinging stellar wind. Unfortunately, very few detections have been made thus far. Here, we us…
The Dynamic Quasiperpendicular Shock: Cluster Discoveries
Bale, S. D.; Krasnoselskikh, V.; Walker, S. N. +9 more
The physics of collisionless shocks is a very broad topic which has been studied for more than five decades. However, there are a number of important issues which remain unresolved. The energy repartition amongst particle populations in quasiperpendicular shocks is a multi-scale process related to the spatial and temporal structure of the electrom…
Young Stellar Objects in Lynds 1641: Disks, Accretion, and Star Formation History
Fang, Min; Henning, Thomas; van Boekel, Roy +3 more
We investigate the young stellar objects (YSOs) in the Lynds 1641 (L1641) cloud using multi-wavelength data including Spitzer, WISE, the Two Micron All Sky Survey, and XMM covering ~1390 YSOs across a range of evolutionary stages. In addition, we targeted a sub-sample of YSOs for optical spectroscopy with the MMT/Hectospec and the MMT/Hectochelle.…
Embedded Protostars in the Dust, Ice, and Gas In Time (DIGIT) Herschel Key Program: Continuum SEDs, and an Inventory of Characteristic Far-infrared Lines from PACS Spectroscopy
Herczeg, Gregory J.; Lee, Jeong-Eun; Dunham, Michael M. +18 more
We present 50-210 µm spectral scans of 30 Class 0/I protostellar sources, obtained with Herschel-PACS, and 0.5-1000 µm spectral energy distributions, as part of the Dust, Ice, and Gas in Time Key Program. Some sources exhibit up to 75 H2O lines ranging in excitation energy from 100 to 2000 K, 12 transitions of OH, and CO rot…
Forecasting a Coronal Mass Ejection's Altered Trajectory: ForeCAT
Kay, C.; Opher, M.; Evans, R. M.
To predict whether a coronal mass ejection (CME) will impact Earth, the effects of the background on the CME's trajectory must be taken into account. We develop a model, ForeCAT (Forecasting a CME's Altered Trajectory), of CME deflection due to magnetic forces. ForeCAT includes CME expansion, a three-part propagation model, and the effects of drag…
Planck intermediate results. VIII. Filaments between interacting clusters
Böhringer, H.; Kneissl, R.; Bernard, J. -P. +205 more
Context. About half of the baryons of the Universe are expected to be in the form of filaments of hot and low-density intergalactic medium. Most of these baryons remain undetected even by the most advanced X-ray observatories, which are limited in sensitivity to the diffuse low-density medium.
Aims: The Planck satellite has provided hundreds …