Search Publications
Search for methane on Mars: Observations, interpretation and future work
Encrenaz, Thérèse
The detection of methane on Mars has been reported by three different teams in 2004. Two of them used ground-based high-resolution spectroscopy in the near infrared range. The third one used the Planetary Fourier Spectrometer aboard Mars Express. Among the data sets, two of them reported a mean CH4 mixing ratio of 10 ppb. However, these…
A conceptual model for explanation of Albedo changes in Martian craters
Yue, Z.; Zhu, M.; Xie, H. +3 more
We propose a conceptual model to interpret AM/PM high albedo events (HAEs) in crater interiors at the Martian seasonal polar caps. This model consists of two components: (1) a relatively permanent high-albedo water-ice body exposed in a crater interior and (2) a variable crater albedo in response to aerosol optical depth, dust contamination, and H…
Conjugate observation of sharp dynamical boundary in the inner magnetosphere by Cluster and DMSP spacecraft and ground network
Nakamura, R.; Sergeev, V. A.; Baumjohann, W. +9 more
We investigate an unusual sharp boundary separating two plasma populations (inner magnetospheric plasma with high fluxes of energetic particles and plasma sheet) observed by the Cluster quartet near its perigee on 16 December 2003. Cluster was in a pearl-on-string configuration at 05:00 MLT and mapped along magnetic field lines to ~8 9 RE
RR Lyrae stars in M31 globular clusters: B514
Clementini, G.; Marconi, M.; Cacciari, C. +8 more
We present preliminary results of a variable star search in the metal-poor globular cluster B514 of the Andromeda galaxy (M31), based on Hubble Space Telescope Wide Field Planetary Camera 2 and Advanced Camera for Surveys observations. A large number of RR Lyrae stars have been identified for the first time in a globular cluster of M31. The averag…
EUV spectral energy distribution of quasars restored from associated absorbers
Reimers, D.; Levshakov, S. A.; Agafonova, I. I. +2 more
Aims: We reconstruct the spectral shape of the quasar ionizing radiation in the extreme-UV range (1 Ryd ≤ E < 10 Ryd) from the analysis of narrow absorption lines (NAL) of the associated systems.
Methods: The computational technique for inverse spectroscopic problems - a Monte Carlo Inversion augmented by the spectral shape recovering proce…
Structure of the near-Earth plasma sheet during tailward flows
Balogh, A.; Nakamura, R.; Fujimoto, M. +10 more
A detailed analysis of successive tailward flow bursts in the near-Earth magnetotail (X~-19 RE) plasma sheet is performed on the basis of in-situ multi-point observations by the Cluster spacecraft on 15 September 2001. The tailward flows were detected during a northward IMF interval, 2.5 h after a substorm expansion. Each flow burst (V<…
Modeling PSBL high speed ion beams observed by Cluster and Double Star
Bosqued, Jean-Michel; El-Alaoui, Mostafa; Walker, Raymond J. +3 more
On October 8, 2004, the Cluster and Double Star spacecraft crossed the near-Earth (12 19 RE) magnetotail neutral sheet during the recovery phase of a small, isolated substorm. Although they were separated in distance by ∼7 RE and in time by ∼30 min, both Cluster and Double Star observed steady, but highly structured Earthward…
The Non-Thermal Radio Jet Toward the NGC 2264 Star Formation Region
Rodríguez, Luis F.; Trejo, Alfonso
We report sensitive VLA 3.6 cm radio observations toward the head of the Cone Nebula in NGC 2264, made in 2006. The purpose of these observations was to study a non-thermal radio jet recently discovered, which appears to emanate from the head of the Cone Nebula. The jet is highly polarized, with well-defined knots, and one-sided. Comparison of our…
Confirmation of the binary status of Chamaeleon Hα 2 - a very young low-mass binary in Chamaeleon
Neuhäuser, R.; Schmidt, T. O. B.; Vogt, N. +3 more
Context: Neuhäuser & Comerón (1998, Science, 282, 83; 1999, A&A, 350, 612) presented direct imaging evidence, as well as first spectra, of several young stellar and sub-stellar M6- to M8-type objects in the Cha I dark cloud. One of these objects is Cha Hα 2, classified as brown dwarf candidate in several publications and suggested as possi…
Refining the Parallax in Visual Double Stars Using Orbital and Spectral Data: Application to the System of the K0 Giants, A 1808
Docobo, J. A.; Andrade, M.; Tamazian, V. S. +2 more
In this paper, we show how Hipparcos parallaxes of distant visual binaries (πHip <~ 10 mas) can be refined. This is accomplished by using relevant orbital and spectral data. To this end, we study the pair of K0 giants, A 1808. A revised orbit of this system is presented that was calculated by taking into account a set of interferomet…