Search Publications
Solar flares observed by Rosetta at comet 67P/Churyumov-Gerasimenko
Henri, P.; Edberg, N. J. T.; Simon Wedlund, C. +6 more
Context. The Rosetta spacecraft made continuous measurements of the coma of comet 67P/Churyumov-Gerasimenko (67P) for more than two years. The plasma in the coma appeared very dynamic, and many factors control its variability.
Aims: We wish to identify the effects of solar flares on the comet plasma and also their effect on the measurements b…
Multiwavelength Stereoscopic Observation of the 2013 May 1 Solar Flare and CME
Krucker, Säm; Masuda, Satoshi; Mitrofanov, Igor +7 more
A M-class behind-the-limb solar flare on 2013 May 1 (SOL2013-05-01T02:32), accompanied by a (∼400 km s-1) coronal mass ejection (CME), was observed by several space-based observatories with different viewing angles. We investigated the RHESSI-observed occulted hard X-ray (HXR) emissions that originated at least 0.1 {R}{{S}} a…
Faint solar analogues at the limit of no reddening. Precise atmospheric parameters from moderate low-resolution spectra
Porto de Mello, G. F.; Lorenzo-Oliveira, D.; Giribaldi, R. E. +2 more
Context. The flux distribution of solar analogues is required for calculating the spectral albedo of solar system bodies such as asteroids and trans-Neptunian objects. Ideally a solar analogue should be comparatively faint as the target of interest, but very few analogues fainter than V = 9 mag have been identified so far. Only atmospheric paramet…
Heavy Ion Flows in the Upper Ionosphere of the Venusian North Pole
Fedorov, A.; Barabash, S.; Futaana, Y. +5 more
We investigate the heavy ion density and velocity in the Venusian upper ionosphere near the North Pole, using the Ion Mass Analyzer, a part of the Analyzer of Space Plasmas and Energetic Atoms 4, together with the magnetic field instruments on Venus Express. The measurements were made during June-July 2014, covering the aerobraking campaign with l…
Can High-Mode Magnetohydrodynamic Waves Propagating in a Spinning Macrospicule Be Unstable Due to the Kelvin-Helmholtz Instability?
Zhelyazkov, I.; Chandra, R.
We investigate the conditions at which high-mode magnetohydrodynamic (MHD) waves propagating in a spinning solar macrospicule can become unstable with respect to the Kelvin-Helmholtz instability (KHI). We consider the macrospicule as a weakly twisted cylindrical magnetic flux tube moving along and rotating around its axis. Our study is based on th…
Evolution of the Three-dimensional Shape of Passively Evolving and Star-forming Galaxies at z < 1
Kajisawa, Masaru; Satoh, Yuki K.; Himoto, Kazuharu G.
Using the HST/ACS I F814W-band data, we investigated the distribution of apparent axial ratios of ∼21,000 galaxies with M V < -20 at 0.2 < z < 1.0 in the COSMOS field as a function of stellar mass, specific star formation rate (sSFR), and redshift. We statistically estimated intrinsic 3D shapes of these galaxies by…
Spatially resolving the atmosphere of the non-Mira-type AGB star SW Vir in near-infrared molecular and atomic lines with VLTI/AMBER
Ohnaka, K.; Hadjara, M.; Maluenda Berna, M. Y. L.
Aims: We present a near-infrared spectro-interferometric observation of the non-Mira-type, semiregular asymptotic giant branch star SW Vir. Our aim is to probe the physical properties of the outer atmosphere with spatially resolved data in individual molecular and atomic lines.
Methods: We observed SW Vir in the spectral window between 2…
Current Density in Saturn's Equatorial Current Sheet: Cassini Magnetometer Observations
Arridge, C. S.; Martin, C. J.
The equatorial current sheet at Saturn is the result of a rapidly rotating magnetosphere. The sheet itself exhibits periodic seasonal and diurnal movements as well as aperiodic movements of a currently unknown origin, along with periodic thickening and thinning of the magnetodisc, and azimuthal changes in the thickness due to local effects in the …
Observing Exoplanets in the Near-Infrared from a High Altitude Balloon Platform
Parmentier, Vivien; Lewis, Nikole K.; Pascale, Enzo +8 more
Although there exists a large sample of known exoplanets, little data exists that can be used to study their global atmospheric properties. This deficiency can be addressed by performing phase-resolved spectroscopy — continuous spectroscopic observations of a planet’s entire orbit about its host star — of transiting exoplanets. Planets with charac…
On the structure of the Pleiades cluster
Krełowski, J.; Galazutdinov, G. A.; Strobel, A. +2 more
The data available on the distances (both from Gaia DR2 and those determined from interstellar Ca II lines) to the brightest stars in the Pleiades (`Seven Sisters' and their `parents') suggest that these stars highly likely do not form a compact cluster but are localized in front of the main (Pleiades) cluster - at a distance close to that given b…