Search Publications
A gas-phase primordial origin of O2 in comet 67P/Churyumov-Gerasimenko
Williams, D. A.; Wilson, T. G.; Rawlings, J. M. C.
Recent observations made by the Rosetta/ROSINA instrument have detected molecular oxygen in the coma of comet 67P/Churyumov-Gerasimenko with abundances at the 1-10 per cent level relative to H2O. Previous studies have indicated that the likely origin of the O2 may be surface chemistry of primordial (dark cloud) origin, requir…
X-Ray Observations of an Intermediate Polar V2400 Oph
Pandey, J. C.; Singh, Harinder P.; Joshi, Arti
Based on the X-ray observations from XMM-Newton and Suzaku satellites at four different epochs, we present temporal and spectral properties of an intermediate polar (IP) V2400 Oph (=RX J1712.6-2414). The X-ray variations are found to occur at the spin and synodic periods and are derived to be 929 s and 1003 s, respectively. The X-ray spectrum is s…
Eclipsing Binaries in the Open Cluster Ruprecht 147. II. Epic 219568666
Torres, Guillermo; Vanderburg, Andrew; Beichman, Charles A. +7 more
We report our spectroscopic monitoring of the detached, grazing, and slightly eccentric 12 day double-lined eclipsing binary EPIC 219568666 in the old nearby open cluster Ruprecht 147. This is the second eclipsing system to be analyzed in this cluster, following our earlier study of EPIC 219394517. Our analysis of the radial velocities combined wi…
A multiwavelength study of the debris disc around 49 Cet
Henning, Thomas; Lee, Eve J.; Boccaletti, Anthony +17 more
In a multiwavelength study of thermal emission and scattered light images we analyse the dust properties and structure of the debris disc around the A1-type main-sequence star 49 Cet. As a basis for this study, we present new scattered light images of the debris disc known to possess a high amount of both dust and gas. The outer region of the disc…
Some relationships between radiative and atmospheric quantities through 1D NLTE modeling of prominences in the Mg II lines
Vial, J. -C.; Zhang, P.; Buchlin, É.
Context. With more than four years of IRIS observations, and in order to avoid building customized diagnostics for each observation, it is useful to derive some simple relations between spectra and physical quantities. This is even more useful for the k and h lines of Mg II, which require complex non-local-thermodynamic-equilibrium NLTE treatments…
Metallicity estimates of young clusters in the Magellanic Clouds from Strömgren photometry of supergiant stars
Piatti, Andrés E.; Pietrzyński, Grzegorz; Graczyk, Dariusz +2 more
We present results obtained from Strömgren photometry of 13 young (∼30-220 Myr) Magellanic Cloud (MC) clusters, most of them lacking in the literature from direct metallicity measurements. We derived for them [Fe/H] values from a high-dispersion spectroscopy-based empirical calibration of the Strömgren metallicity sensitive index m1 for…
The Rocky-Like Behavior of Cometary Landslides on 67P/Churyumov-Gerasimenko
Bertaux, Jean-Loup; Da Deppo, Vania; Naletto, Giampiero +36 more
Landslides have been identified on several solar system bodies, and different mechanisms have been proposed to explain their runout length. We analyze images from the Rosetta mission and report the global characterization of such features on comet 67P/Churyumov-Gerasimenko's surface. By assuming the height to runout length as an approximation for …
Hubble Space Telescope photometry of multiple stellar populations in the inner parts of NGC 2419
Hernandez, Svea; Brodie, Jean; Larsen, Søren S. +2 more
We present new deep imaging of the central regions of the remote globular cluster NGC 2419, obtained with the F343N and F336W filters of the Wide Field Camera 3 on board the Hubble Space Telescope. The new data are combined with archival imaging to constrain nitrogen and helium abundance variations within the cluster. We find a clearly bimodal dis…
Chandra, MDM, Swift, and NuSTAR Observations Confirming the SFXT Nature of AX J1949.8+2534
Halpern, Jules P.; Hare, Jeremy; Rahoui, Farid +3 more
AX J1949.8+2534 is a candidate supergiant fast X-ray transient (SFXT) observed in outburst by the International Gamma-ray Astrophysics Laboratory (IGR J19498+2534). We report on the results of six Neil Gehrels Swift-XRT, one Chandra, and one Nuclear Spectroscopic Telescope Array observation of the source. We find evidence of rapid X-ray variabilit…
Impact of Data Assimilation on Thermal Tides in the Case of Venus Express Wind Observation
Sugimoto, Norihiko; Takagi, Masahiro; Kouyama, Toru
Impacts of horizontal winds assimilation on thermal tides are investigated by using the Venus atmospheric general circulation model for the Earth Simulator local ensemble transform Kalman filter data assimilation system. The assimilated data are horizontal winds derived from Venus ultraviolet images taken by the Venus Monitoring Camera onboard the…