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Electric thruster mode-pruning strategies for trajectory-propulsion co-optimization
Arya, Vishala; Taheri, Ehsan; Junkins, John
Application of idealized constant-specific-impulse, constant-thrust electric thruster performance models or curve-fitted polynomials is quite common for spacecraft trajectory design. However, incorporation of realistic performance models of multi-mode electric thrusters leads to notable challenges, and at the same time, offers unprecedented system…
Search for giant planets around seven white dwarfs in the Hyades cluster with the Hubble Space Telescope
Brandner, Wolfgang; Kopytova, Taisiya; Zinnecker, Hans
Only a small number of exoplanets have been identified in stellar cluster environments. We initiated a high angular resolution direct imaging search using the Hubble Space Telescope (HST) and its Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) instrument for self-luminous giant planets in orbit around seven white dwarfs in the 625 Myr …
BAT99 126: A multiple Wolf-Rayet system in the Large Magellanic Cloud with a massive near-contact binary
Shenar, T.; Sana, H.; Mahy, L. +3 more
Context. BAT99 126 is a multiple system in the Large Magellanic Cloud containing a Wolf-Rayet (WR) star, which has a reported spectroscopic (orbital) period of 25.5 days and a photometric (orbital) period of 1.55 days, and hence is potentially one of the shortest WR binaries known to date. Such short-period binary systems that contain a WR star in…
A Long Term Study of Mars Mesospheric Clouds Seen at Twilight Based on Mars Express VMC Images
Hueso, R.; Sánchez-Lavega, A.; Titov, D. +5 more
We present the first systematic study of clouds observed during twilight on Mars. We analyze images obtained by the Visual Monitoring Camera on Mars Express between 2007 and 2020. Using an automated retrieval algorithm, we found 407 cases of clouds observed at twilight, in which the geometry of the observations allows to derive the minimum altitud…
Comparison of active region upflow and core properties using simultaneous spectroscopic observations from IRIS and Hinode
Barczynski, Krzysztof; Brooks, David H.; Kleint, Lucia +2 more
Context. The origin of the slow solar wind is still an open issue. It has been suggested that upflows at the edge of active regions are a possible source of the plasma outflow and therefore contribute to the slow solar wind.
Aims: We investigate the origin and morphology of the upflow regions and compare the upflow region and the active regio…
The eROSITA Final Equatorial-Depth Survey (eFEDS). An X-ray-bright, extremely luminous infrared galaxy at z = 1.87
Nandra, Kirpal; Ueda, Yoshihiro; Terashima, Yuichi +15 more
In this study, we investigate the X-ray properties of WISE J090924.01+000211.1 (WISEJ0909+0002), an extremely luminous infrared (IR) galaxy (ELIRG) at zspec = 1.871 in the eROSITA Final Equatorial-Depth Survey. WISEJ0909+0002 is a WISE 22 µm source, located in the GAMA-09 field, which was detected by eROSITA during the performance…
The first GeV flare of the radio-loud narrow-line Seyfert 1 galaxy PKS 2004-447
Buson, S.; Wilms, J.; Kadler, M. +8 more
Context. On 2019 October 25, the Fermi-Large Area Telescope observed the first ever γ-ray flare from the radio-loud narrow-line Seyfert 1 galaxy PKS 2004−447 (z = 0.24). Prior to this discovery, only four sources of this type had shown a flare at gigaelectronvolt energies.
Aims: We report on follow-up observations in the radio, optical-UV, an…
Cold ion energization at separatrices during magnetic reconnection
Divin, A.; Deca, J.; Markidis, S. +5 more
Separatrices of magnetic reconnection host intense perpendicular Hall electric fields. The fields are produced by the decoupling of the ion and electron components and are associated with the in-plane electrostatic potential drop between the inflow and outflow regions. The width of these structures is typically less than the ion inertial length, w…
Sympathetic Standard and Blowout Coronal Jets Observed in a Polar Coronal Hole
Shen, Yuandeng; Zhou, Chengrui; Zhou, Xinping +4 more
We present the sympathetic eruption of a standard and a blowout coronal jet originating from two adjacent coronal bright points (CBP1 and CBP2) in a polar coronal hole, using soft X-ray and extreme-ultraviolet observations respectively taken by the Hinode and the Solar Dynamics Observatory. In the event, a collimated jet with obvious westward late…
The Structural Connection between Coronal Mass Ejection Flux Ropes near the Sun and at 1 au
Gopalswamy, N.; Xie, H.; Akiyama, S.
We have performed the first comprehensive statistical analysis comparing flux rope (FR) structures of coronal mass ejections (CMEs) near the Sun and at 1 au, using Solar and Heliospheric Observatory and Solar Terrestrial Relations Observatory measurements for the two full solar cycles 23 and 24. This study aims to investigate the physical connecti…