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Spatially Highly Resolved Solar-wind-induced Magnetic Field on Venus
He, Maosheng; Vogt, Joachim; Zhang, Tielong +2 more
The current work investigates the Venusian solar-wind-induced magnetosphere at a high spatial resolution using all Venus Express (VEX) magnetic observations through an unbiased statistical method. We first evaluate the predictability of the interplanetary magnetic field (IMF) during VEX's Venusian magnetospheric transits and then map the induced f…
Albert Galeev: The Problem of Metastability and Explosive Reconnection
Popov, V. Yu.; Zelenyi, L. M.; Grigorenko, E. E. +2 more
−Albert Abubakirovich Galeev is a Soviet and Russian expert in plasma physics who actively contributed to fusion research. In the early 1970s, he became a head of department at the Space Research Institute of the Academy of Sciences of USSR and began devoting most of his time to the problems of the physics of space plasma and made a very important…
Exploring the robustness of Keplerian signals to the removal of active and telluric features
Butler, R. P.; Jones, H. R. A.; Vogt, S. +2 more
We examine the influence of activity- and telluric-induced radial velocity (RV) signals on high-resolution spectra taken with an iodine absorption cell. We exclude 2- $\mathring{\rm A}$ spectral chunks containing active and telluric lines based on the well-characterized K1V star α Centauri B and illustrate the method on Epsilon Eridani - an active…
Light Element Abundances and Multiple Populations in M53
Vesperini, Enrico; Gerber, Jeffrey M.; Friel, Eileen D.
We present results from a study of 94 red giant stars in the globular cluster M53. We use low-resolution spectra to measure the strength of CN and CH features at ∼3800 and 4300 Å, respectively. The strengths of these features are used to classify stars into a CN-enhanced and CN-normal population and to measure C and N abundances in all 94 stars. W…
A possible far-ultraviolet flux-dependent core mass function in NGC 6357
Giannetti, A.; Massi, F.; Wouterloot, J. G. A. +2 more
Context. NGC 6357 is a galactic star-forming complex (d ~ 1.7 kpc) composed of several HII regions, a few young stellar clusters, and giant molecular clouds. In particular, the HII regions G353.2+0.9, G353.1+0.6, and G353.2+0.7 are associated with three young clusters; the most prominent of these, Pismis 24, contains some of the most massive stars…
Detection of H2 in the TWA 7 System: A Probable Circumstellar Origin
France, Kevin; Johns-Krull, Christopher M.; Carpenter, John M. +4 more
Using HST-COS far-UV spectra, we have discovered warm molecular hydrogen in the TWA 7 system. TWA 7, a ~9 Myr old M2.5 star, has a cold debris disk and has previously shown no signs of accretion. Molecular hydrogen is expected to be extremely rare in a debris disk. While molecular hydrogen can be produced in starspots or the lower chromospheres of…
An investigation of planetary nebulae accompanying PG 1159 central stars, based on Gaia DR2 measurements
Ali, Alaa; Alharbi, Wedad R.
This article discusses the physical and kinematical characteristics of planetary nebulae accompanying PG 1159 central stars. The study is based on the parallax and proper motion measurements recently offered by the Gaia space mission. Two approaches were used to investigate the kinematical properties of the sample. The results revealed that most o…
Dynamics of nanodust in the vicinity of a stellar corona: Effect of plasma corotation
Czechowski, A.; Mann, I.
Context. In the vicinity of the Sun or other stars, the motion of the coronal and stellar wind plasma must include some amount of corotation, which could affect the dynamics of charged dust particles. In the case of the Sun, this region is now investigated in situ by the Parker Solar Probe. Charged dust particles coming from the vicinity of the Su…
SOFIA upGREAT/FIFI-LS Emission-line Observations of Betelgeuse during the Great Dimming of 2019/2020
Harper, Graham M.; Guinan, Edward F.; Fadda, Dario +12 more
We report NASA-DLR SOFIA upGREAT circumstellar [O I] 63.2 µm and [C II] 157.7 µm emission profiles and FIFI-LS [O I] 63.2 µm, [O I] 145.5 µm, and [C II] 157.7 µm fluxes obtained shortly after Betelgeuse's 2019/2020 Great Dimming event. Haas et al. noted a potential correlation between the [O I] 63.2 µm flux and …
A time-series VI study of the variable stars of the globular cluster NGC 6397
Arellano Ferro, A.; Calderón, J. H.; Lázaro, C. +4 more
We present a new time-series VI CCD photometry of the globular cluster NGC 6397, from which we obtained and analysed the light curves of 35 variables carefully identified in the cluster field. We assessed the membership of the variables with an astrometric analysis based on Gaia DR2 data. The cluster colour-magnitude diagram was differentially der…