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Investigating the behaviour of neutral hydrogen Lyα spectral line width in polar coronal holes at solar minimum
Susino, R.; Antonucci, E.; Spadaro, D. +2 more
We investigate the behaviour of the H I Lyα spectral line widths measured by UVCS/SOHO in polar coronal holes at minimum of solar magnetic activity. The line widths are reported to significantly increase up to 3 R⊙, while above 3 R⊙ there is observational evidence of either nearly constant or slightly decreasing values. We ad…
Nanograin Density Outside Saturn’s A Ring
Persoon, A. M.; Johnson, Robert E.; Tseng, Wei-Ling +1 more
The observed disparity between the radial dependence of the ion and electron densities measured by the Cassini plasma (CAPS) and radio (RPWS) science instruments are used to show that the region between the outer edge of Saturn’s main rings and its tenuous G ring is permeated with small charged grains (nanograins). These grains emanate from the ed…
Temporal relations between magnetic bright points and the solar sunspot cycle
Van Doorsselaere, Tom; Utz, Dominik; Muller, Richard
The Sun shows a global magnetic field cycle traditionally best visible in the photosphere as a changing sunspot cycle featuring roughly an 11-year period. In addition we know that our host star also harbours small-scale magnetic fields often seen as strong concentrations of magnetic flux reaching kG field strengths. These features are situated in …
Exploring accretion disk physics and black hole growth with regular monitoring of ultrafast active galactic nucleus winds
Pounds, K.; Lobban, A.; Nixon, C.
Fifteen years of XMM-Newton observations have established that ultrafast highly ionized winds (UFOs) are common in radio-quiet active galactic nucleus (AGN). A simple theory of Eddington-limited accretion correctly predicts the typical velocity (∼0.1c) and high ionization of such winds, with observed flow energy capable of ejecting star-forming ga…
Ion-Scale Sideband Waves and Filament Formation: Alfvénic Impact on Heliospheric Plasma Turbulence
Motschmann, Uwe; Narita, Yasuhito
A mini-review is given about two recent discoveries in the solar wind turbulence research on ion-kinetic scales: the existence of sideband waves (or breakdown of the linear mode wave picture) and the wavevector anisotropy leading to a persistent filament formation in a wide range of plasma beta.
Decay of COSAC and Ptolemy mass spectra at comet 67P/Churyumov-Gerasimenko
Krüger, Harald; McKenna-Lawlor, Susan; Gautier, Thomas +11 more
Context. The Rosetta lander Philae successfully landed on the nucleus of comet 67P/Churyumov-Gerasimenko on 12 November 2014. Philae is equipped with two gas analysers: The Cometary Sampling and Composition experiment (COSAC) and the gas chromatograph and mass spectrometer Ptolemy.
Aims: COSAC is designed for in situ analysis of organic molec…
The formation of superdense plasma sheet in association with the IMF turning from northward to southward
Lavraud, Benoit; Thomsen, Michelle F.; Liang, En-Wei +3 more
We have studied two events in which relatively superdense plasma appeared near geosynchronous orbit after the interplanetary magnetic field (IMF) changed from a long period of northward condition to southward condition. We used the magnetosphere MHD model Open Geospace General Circulation Model to simulate these two events and compared the simulat…
The Luminous Blue Variable RMC 127 as Seen with ALMA and ATCA
Paladini, R.; Umana, G.; Bauer, F. E. +12 more
We present ALMA and ATCA observations of the luminous blue variable RMC 127. The radio maps show for the first time the core of the nebula and evidence that the nebula is strongly asymmetric with a Z-pattern shape. Hints of this morphology are also visible in the archival Hubble Space Telescope {{H}}α image, which overall resembles the radio emiss…
3XMM J181923.7-170616: An X-Ray Binary with a 408 s Pulsar
Qiu, Hao; Zhou, Ping; Xu, Xiaojie +2 more
We carry out a dedicated study of 3XMM J181923.7-170616 with an approximate pulsation period of 400 s using the XMM-Newton and Swift observations spanning across nine years. We have refined the period of the source to 407.904(7) s (at epoch MJD 57142) and constrained the 1σ upper limit on the period derivative \dot{P}≤slant 1.1× {10}-8 …
The lack of X-ray pulsations in the extreme helium star BD+37°442 and its possible stellar wind X-ray emission
Mereghetti, Sandro; Esposito, Paolo; Tiengo, Andrea +1 more
We report the results of a new XMM-Newton observation of the helium-rich hot subdwarf BD+37°442 carried out in 2016 February. The possible periodicity at 19 s seen in a 2011 shorter observation is not confirmed, thus dismissing the evidence for a binary nature. This implies that the observed soft X-ray emission, with a luminosity of a few 103…