TY - THES A1 - Washüttl, Albert T1 - EI Eridani and the art of doppler imaging : a long-term study N2 - Das Verständnis magnetisch verursachter Aktivität auf Sternen sowie der zugrundeliegenden Dynamoprozesse ist von fundamentaler Bedeutung für das Verständnis von Entstehung und Entwicklung von Sternen sowie des Lebens im Universum. Sichtbare Erscheinungen dieser stellaren Aktivität sind u.a. Sternflecken, welche als Indikatoren des zugrundeliegenden Magnetfeldes dienen. Solche Flecken können auf anderen Sternen als der Sonne nicht direkt beobachtet werden, zumal mit den heutigen technischen Mitteln eine Auflösung der Oberfläche selbst der benachbarten Sterne unmöglich ist. Eine indirekte Rekonstruktionsmethode namens 'Doppler Imaging' erlaubt es jedoch, auf die Temperaturverteilung auf der Sternoberfläche zu schließen. Für diese Arbeit wurden elf Jahre kontinuierlicher spektroskopischer Beobachtungen des aktiven Doppelsterns EI Eridani herangezogen, um insgesamt 34 Dopplerkarten zu erstellen. In der Folge wird versucht, eine Grundlage zu schaffen für die Analyse des zweidimensionalen Informationsgehalts dieser Karten. Drei Oberflächenkartenparameter werden vorgeschlagen: gemittelte Temperatur, getrennt für verschiedenen stellare Breitenbänder; relative Fleckenhäufigkeit; und, zum Zwecke der Auswertung der strukturellen Temperaturverteilung, Längen- und Breiten-Ortsfunktion der Sternfleckenhäufung. Die resultierenden Werte zeigen deutlich, daß kein zeitlicher Zusammenhang mit dem photometrischen Aktivitätszyklus besteht. Die Morphologie der Fleckenverteilung bleibt während des kompletten Beobachtungszeitraums im wesentlichen konstant. Im Gegensatz zur Sonne gibt es also, im beobachteten Zeitraum und innerhalb der bestehenden Genauigkeit, keinen Fleckenzyklus auf dem aktiven Stern EI Eri. Darüberhinaus wurde eine ausführliche Studie der stellaren Parameter von EI Eri und eine vorläufige Abschätzung der differentiellen Rotation auf EI Eri durchgeführt, die eine anti-solare Ausrichtung aufzuweisen scheint, d.h. der Pol rotiert schneller als der Äquator. N2 - Understanding stars, their magnetic activity phenomena and the underlying dynamo action is the foundation for understanding 'life, the universe and everything' - as stellar magnetic fields play a fundamental role for star and planet formation and for the terrestrial atmosphere and climate. Starspots are the fingerprints of magnetic field lines and thereby the most important sign of activity in a star's photosphere. However, they cannot be observed directly, as it is not (yet) possible to spacially resolve the surfaces of even the nearest neighbouring stars. Therefore, an indirect approach called 'Doppler imaging' is applied, which allows to reconstruct the surface spot distribution on rapidly rotating, active stars. In this work, data from 11 years of continuous spectroscopic observations of the active binary star EI Eridani are reduced and analysed. 34 Doppler maps are obtained and the problem of how to parameterise the information content of Doppler maps is discussed. Three approaches for parameter extraction are introduced and applied to all maps: average temperature, separated for several latitude bands; fractional spottedness; and, for the analysis of structural temperature distribution, longitudinal and latitudinal spot-occurrence functions. The resulting values do not show a distinct correlation with the proposed activity cycle as seen from photometric long-term observations, thereby suggesting that the photometric activity cycle is not accompanied by a spot cycle as seen on the Sun. The general morphology of the spot pattern on EI Eri remains persistent for the whole period of 11 years. In addition, a detailed parameter study is performed. Improved orbital parameters suggest that EI Eri might be complemented by a third star in a wide orbit of about 19 years. Preliminary differential rotation measurements are carried out, indicating an anti-solar orientation. T2 - EI Eridani and the art of doppler imaging : a long-term study KW - Sterne KW - Aktivität KW - Sternflecken KW - Zyklus KW - stars KW - activity KW - spots KW - cycle KW - binaries KW - late-type Y1 - 2004 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-0001714 ER - TY - JOUR A1 - Verma, Meetu A1 - Kummerow, P. A1 - Denker, Carsten T1 - On the extent of the moat flow in axisymmetric sunspots JF - Astronomische Nachrichten = Astronomical notes N2 - Unipolar, axisymmetric sunspots are figuratively called “theoretician's sunspots” because their simplicity supposedly makes them more suitable for theoretical descriptions or numerical models. On November 18, 2013, a very large specimen (active region NOAA 11899) crossed the central meridian of the sun. The moat flow associated with this very large spot is quantitatively compared to that of a medium and a small sunspot to determine the extent of the moat flow in different environments. We employ continuum images and magnetograms of the Helioseismic and Magnetic Imager (HMI) as well as extreme ultraviolet (EUV) images at λ160 nm of the Atmospheric Imaging Assembly (AIA), both on board the Solar Dynamics Observatory (SDO), to measure horizontal proper motions with Local Correlation Tracking (LCT) and flux transport velocities with the Differential Affine Velocity Estimator (DAVE). We compute time-averaged flow maps (±6 hr around meridian passage) and radial averages of photometric, magnetic, and flow properties. Flow fields of a small- and a medium-sized axisymmetric sunspot provide the context for interpreting the results. All sunspots show outward moat flow and the advection of moving magnetic features (MMFs). However, the extent of the moat flow varies from spot to spot, and a correlation of flow properties with size is tenuous, if at all present. The moat flow is asymmetric and predominantly in the east–west direction, whereby deviations are related to the tilt angle of the sunspot group as well as to the topology and activity level of the trailing plage. KW - activity KW - data analysis KW - image processing KW - photosphere KW - sunspots Y1 - 2018 U6 - https://doi.org/10.1002/asna.201813482 SN - 0004-6337 SN - 1521-3994 VL - 339 IS - 4 SP - 268 EP - 276 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Poppenhäger, Katja T1 - How stars and planets interact BT - A look through the high-energy window JF - Astronomische Nachrichten = Astronomical notes N2 - The architecture of exoplanetary systems is often different from the solar system, with some exoplanets being in close orbits around their host stars and having orbital periods of only a few days. In analogy to interactions between stars in close binary systems, one may expect interactions between the star and the exoplanet as well. From theoretical considerations, effects on the host star through tidal and magnetic interaction with the exoplanet are possible; for the exoplanet, some interesting implications are the evaporation of the planetary atmosphere and potential effects on the planetary magnetism. In this review, several possible interaction pathways and their observational prospects and existing evidence are discussed. A particular emphasis is put on observational opportunities for these kinds of effects in the high-energy regime. KW - magnetic fields KW - planet-star interactions KW - stars KW - activity KW - X-rays Y1 - 2019 U6 - https://doi.org/10.1002/asna.201913619 SN - 0004-6337 SN - 1521-3994 VL - 340 IS - 4 SP - 329 EP - 333 PB - Wiley-VCH CY - Weinheim ER - TY - GEN A1 - Kowalski, Gabriele Joanna A1 - Grimm, Volker A1 - Herde, Antje A1 - Guenther, Anja A1 - Eccard, Jana T1 - Does Animal Personality Affect Movement in Habitat Corridors? BT - Experiments with Common Voles (Microtus arvalis) Using Different Corridor Widths T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - Animal personality may affect an animal’s mobility in a given landscape, influencing its propensity to take risks in an unknown environment. We investigated the mobility of translocated common voles in two corridor systems 60 m in length and differing in width (1 m and 3 m). Voles were behaviorally phenotyped in repeated open field and barrier tests. Observed behavioral traits were highly repeatable and described by a continuous personality score. Subsequently, animals were tracked via an automated very high frequency (VHF) telemetry radio tracking system to monitor their movement patterns in the corridor system. Although personality did not explain movement patterns, corridor width determined the amount of time spent in the habitat corridor. Voles in the narrow corridor system entered the corridor faster and spent less time in the corridor than animals in the wide corridor. Thus, landscape features seem to affect movement patterns more strongly than personality. Meanwhile, site characteristics, such as corridor width, could prove to be highly important when designing corridors for conservation, with narrow corridors facilitating faster movement through landscapes than wider corridors. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 747 KW - activity KW - animal personality KW - wildlife corridors KW - habitat connectivity KW - individual differences KW - rodents Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-435770 SN - 1866-8372 IS - 747 ER - TY - JOUR A1 - Kowalski, Gabriele Joanna A1 - Grimm, Volker A1 - Herde, Antje A1 - Guenther, Anja A1 - Eccard, Jana T1 - Does Animal Personality Affect Movement in Habitat Corridors? BT - Experiments with Common Voles (Microtus arvalis) Using Different Corridor Widths JF - Animals N2 - Animal personality may affect an animal’s mobility in a given landscape, influencing its propensity to take risks in an unknown environment. We investigated the mobility of translocated common voles in two corridor systems 60 m in length and differing in width (1 m and 3 m). Voles were behaviorally phenotyped in repeated open field and barrier tests. Observed behavioral traits were highly repeatable and described by a continuous personality score. Subsequently, animals were tracked via an automated very high frequency (VHF) telemetry radio tracking system to monitor their movement patterns in the corridor system. Although personality did not explain movement patterns, corridor width determined the amount of time spent in the habitat corridor. Voles in the narrow corridor system entered the corridor faster and spent less time in the corridor than animals in the wide corridor. Thus, landscape features seem to affect movement patterns more strongly than personality. Meanwhile, site characteristics, such as corridor width, could prove to be highly important when designing corridors for conservation, with narrow corridors facilitating faster movement through landscapes than wider corridors. KW - activity KW - animal personality KW - wildlife corridors KW - habitat connectivity KW - individual differences KW - rodents Y1 - 2019 U6 - https://doi.org/10.3390/ani9060291 SN - 2076-2615 VL - 9 IS - 6 PB - MDPI CY - Basel ER - TY - JOUR A1 - Gonzalez-Chavarria, Ivan A1 - Duprat, Felix A1 - Roa, Francisco J. A1 - Jara, Nery A1 - Toledo, Jorge R. A1 - Miranda, Felipe A1 - Becerra, Jose A1 - Inostroza, Alejandro A1 - Kelling, Alexandra A1 - Schilde, Uwe A1 - Heydenreich, Matthias A1 - Paz, Cristian T1 - Maytenus disticha extract and an isolated β-Dihydroagarofuran induce mitochondrial depolarization and apoptosis in human cancer cells by increasing mitochondrial reactive oxygen species JF - Biomolecules N2 - Maytenus disticha (Hook F.), belonging to the Celastraceae family, is an evergreen shrub, native of the central southern mountains of Chile. Previous studies demonstrated that the total extract of M. disticha (MD) has an acetylcholinesterase inhibitory activity along with growth regulatory and insecticidal activities. beta-Dihydroagarofurans sesquiterpenes are the most active components in the plant. However, its activity in cancer has not been analyzed yet. Here, we demonstrate that MD has a cytotoxic activity on breast (MCF-7), lung (PC9), and prostate (C4-2B) human cancer cells with an IC50 (mu g/mL) of 40, 4.7, and 5 mu g/mL, respectively, an increasing Bax/Bcl2 ratio, and inducing a mitochondrial membrane depolarization. The beta-dihydroagarofuran-type sesquiterpene (MD-6), dihydromyricetin (MD-9), and dihydromyricetin-3-O-beta-glucoside (MD-10) were isolated as the major compounds from MD extracts. From these compounds, only MD-6 showed cytotoxic activity on MCF-7, PC9, and C4-2B with an IC50 of 31.02, 17.58, and 42.19 mu M, respectively. Furthermore, the MD-6 increases cell ROS generation, and MD and MD-6 induce a mitochondrial superoxide generation and apoptosis on MCF-7, PC9, and C4-2B, which suggests that the cytotoxic effect of MD is mediated in part by the beta-dihydroagarofuran-type that induces apoptosis by a mitochondrial dysfunction. KW - Maytenus disticha KW - beta-dihydroagarofuran-type sesquiterpene KW - dihydromyricetin KW - dihydromyricetin-3-O-beta-glucoside KW - cytotoxic KW - activity KW - Mitochondrial ROS Y1 - 2020 U6 - https://doi.org/10.3390/biom10030377 SN - 2218-273X VL - 10 IS - 3 PB - MDPI CY - Basel ER - TY - JOUR A1 - Hawro, Tomasz A1 - Przybylowicz, Katarzyna A1 - Spindler, Max A1 - Hawro, Marlena A1 - Steć, Michał A1 - Altrichter, Sabine A1 - Weller, Karsten A1 - Magerl, Markus A1 - Reidel, Ulrich A1 - Alarbeed, Ezzat A1 - Alraboni, Ola A1 - Maurer, Marcus A1 - Metz, Martin T1 - The characteristics and impact of pruritus in adult dermatology patients BT - a prospective, cross-sectional study JF - Journal of the American Academy of Dermatology N2 - Background: Pruritus often accompanies chronic skin diseases, exerting considerable burden on many areas of patient functioning; this burden and the features of pruritus remain insufficiently characterized. Objective: To investigate characteristics, including localization patterns, and burden of pruritus in patients with chronic dermatoses. Methods: We recruited 800 patients with active chronic skin diseases. We assessed pruritus intensity, localization, and further characteristics. We used validated questionnaires to assess quality of life, work productivity and activity impairment, anxiety, depression, and sleep quality. Results: Nine out of every 10 patients had experienced pruritus throughout their disease and 73% in the last 7 days. Pruritus often affected the entire body and was not restricted to skin lesions. Patients with moderate to severe pruritus reported significantly more impairment to their sleep quality and work productivity, and they were more depressed and anxious than control individuals and patients with mild or no pruritus. Suicidal ideations were highly prevalent in patients with chronic pruritus (18.5%) and atopic dermatitis (11.8%). Conclusions: Pruritus prevalence and intensity are very high across all dermatoses studied; intensity is linked to impairment in many areas of daily functioning. Effective treatment strategies are urgently required to treat pruritus and the underlying skin disease. ( J Am Acad Dermatol 2021;84:691-700.) KW - activity KW - anxiety KW - depression KW - pruritus KW - quality of life KW - sleep quality KW - suicidal ideations KW - work productivity Y1 - 2021 U6 - https://doi.org/10.1016/J.JAAD.2020.08.035 SN - 0190-9622 SN - 1097-6787 VL - 84 IS - 3 SP - 691 EP - 700 PB - Elsevier CY - Amsterdam [u.a.] ER - TY - THES A1 - Hoffmann, Julia T1 - Influence of artificial light at night on the behavior of small mammals T1 - Der Einfluss von künstlicher nächtlicher Beleuchtung auf das Verhalten von Kleinsäugern N2 - Artificial light at night (ALAN), one form of human-induced rapid environmental change, is continuously spreading in space and time and increasing in intensity as part of the ongoing urbanization. A vast range of animals is known to be affected by ALAN as, among other things, it can mask natural light cues and change both the perceived as well as the actual predation risk. Since ALAN per se is restricted to the night, the majority of studies so far have focused on nocturnal species or behavioral changes during the night. How polyphasic species respond to ALAN has been largely overlooked, although they can possibly carry over effects of nighttime illumination into the day. Additionally, individuals within a species are known to consistently differ in their personality which includes risk-taking behavior. While this implies that ALAN can lead to varying anti-predatory responses in animals within a population, knowledge on this topic is still very limited. This thesis aims at investigating what initial behavioral reaction is caused by ALAN in polyphasic small mammals while also incorporating an animal’s personality. Nighttime and daytime activity, movement and foraging behavior of the bank vole (Myodes glareolus) were investigated in regards to effects of different light intensities and partial illumination in the laboratory. Additionally, changes in intra- and interspecific interactions of bank voles and striped field mice (Apodemus agrarius) subjected to ALAN were studied in experimental populations in semi-natural outdoor enclosures. Chapter I explores whether behavioral responses to ALAN of varying intensity are related to animal personality. Results showed that bank voles reduced movement and foraging already under dim light and that bold animals generally moved and foraged more than shy animals. Exclusively under bright illumination did bold animals exploit the food patches more than shy animals. The results demonstrate that bank voles are affected by light intensities prevalent in urban habitats. Additionally, certain light scenarios might lead to an advantage of and a shift towards certain personality types. Chapter II focusses on the effects of partial ALAN on foraging behavior of animals with varying animal personalities while extending the view towards possible carry-over effects of ALAN into the daytime. While bank voles reduced foraging behavior in illuminated areas at night, they increased foraging behavior in those areas at the subsequent day. Bold individuals generally had lower giving-up densities than shy individuals but this difference was especially pronounced during daytime at formerly illuminated food patches. Thus, ALAN can have carry-over effects into the daytime in polyphasic animals and thus has the potential to affect daytime intra- and interspecific interactions. Chapter III broadens the view from the individual to the population level. Experimental populations consisting of bank voles and striped field mice were established in large outdoor enclosures successively experienced natural and artificial light conditions at night. VHF telemetry data revealed that animals were predominantly active during the day under natural conditions. This difference between day and night vanished under ALAN. Additionally, conspecifics reduced home range overlap, proximity and activity synchrony while boldness was not associated with behavioral changed due to ALAN. The results suggest that ALAN has the potential to alter intraspecific interactions and thus can have fitness consequences on the population level. Overall, the present thesis shows that ALAN can affect nighttime and daytime behavior as well as intraspecific interactions of polyphasic small mammals. Differences in risk- taking behavior of individuals may vary in importance depending on other environmental variables. Thus, this thesis hopefully triggers broadening the view regarding the role of an animal’s personality in coping with ALAN and the effects on daytime behavior and diurnal species. N2 - Künstliche Beleuchtung bei Nacht ist eine Form schnell eintretender Umweltveränderung, die durch den Menschen verursacht wird. Sie breitet sich in Raum und Zeit kontinuierlich aus und nimmt, als Teil der fortschreitenden Urbanisierung, stetig an Intensität zu. Ein breites Spektrum an Tieren wird von künstlicher Beleuchtung beeinflusst, da sie unter anderem natürliche Lichtsignale maskieren und sowohl das wahrgenommene als auch das reale Prädationsrisiko verändern kann. Da künstliche Beleuchtung an sich auf die Nacht beschränkt ist, hat sich ein Großteil der bisher durchgeführten Studien auf ihre Effekte auf nachtaktive Tierarten bzw. nächtliche Verhaltensweisen beschränkt. Jedoch wurde bisher kaum untersucht, auf welche Weise Tiere mit einem polyphasischen Aktivitätsrhythmus auf künstliche Beleuchtung reagieren, obwohl sie möglicherweise Effekte von künstlicher Beleuchtung bei Nacht auf den Tag übertragen können. Zusätzlich ist bekannt, dass sich Individuen einer Art konsistent in ihrer Tierpersönlichkeit unterscheiden, welche ihr Risikoverhalten einschließt. Während dies darauf hindeutet, dass künstliche Beleuchtung bei Nacht unterschiedliche antiprädatorische Verhaltensanpassungen bei Tieren innerhalb einer Population hervorrufen kann, sind die Kenntnisse über diesen Themenkomplex bisher sehr gering. Diese Doktorarbeit hat zum Ziel, die anfänglichen Verhaltensänderungen von polyphasischen Kleinsäugern, welche durch künstliche Beleuchtung bei Nacht hervorgerufen werden, zu untersuchen. Zusätzlich wird die Persönlichkeit der Tiere berücksichtigt. Es wurden Aktivität, Bewegungsmuster und Nahrungssuchverhalten in der Nacht und am Tag von Rötelmäusen (Myodes glareolus) in Bezug auf die Effekte verschiedener Lichtintensitäten und partieller Beleuchtung bei Nacht untersucht. Während diese Versuche im Labor stattfanden, wurde zusätzlich ein Versuch in semi- natürlichen Außengehegen durchgeführt. In diesem lag der Fokus auf Veränderungen in intra- und interspezifischen Interaktionen innerhalb künstlicher Populationen bestehend aus Rötelmäusen und Brandmäusen (Apodemus agrarius), welche bei Nacht künstlicher Beleuchtung ausgesetzt waren. Kapitel I untersucht inwiefern Verhaltensänderungen aufgrund künstlicher Beleuchtung bei Nacht mit der Persönlichkeit der Tiere in Verbindung stehen. Die Ergebnisse zeigen, dass Rötelmäuse ihre Bewegung und die Nahrungssuche bereits unter schwacher nächtlicher Beleuchtung reduzierten. Risikofreudigere Tiere bewegten sich mehr und suchten häufiger nach Nahrung als weniger risikofreudige Tiere. Diese Resultate verdeutlichen, dass Rötelmäuse durch solche Lichtintensitäten beeinträchtigt werden, wie sie für urbane Habitate typisch sind. Bestimmte Lichtszenarien könnten zudem zu einem Vorteil für und eine Selektion auf bestimmte Persönlichkeitstypen führen. Kapitel II konzentriert sich auf die Effekte, welche eine partielle Beleuchtung auf das Nahrungssuchverhalten von Tieren haben kann, welche sich hinsichtlich ihrer Persönlichkeit unterscheiden. Zusätzlich wird untersucht, inwiefern künstliche Beleuchtung bei Nacht auch am Tag zu Verhaltensveränderungen führen kann. Während die Rötelmäuse bei Nacht ihre Nahrungssuche in beleuchteten Bereichen einschränkten, zeigten sie dort eine gesteigerte Nahrungssuche am folgenden Tag. Risikofreudigere Tiere beuteten die Futterstellen stärker aus als weniger risikofreudige Tiere, wobei dieser Unterschied am Tag in den ehemals beleuchteten Futterstellen besonders stark war. Somit kann künstliche Beleuchtung in der Nacht auch Effekte auf das Verhalten von polyphasischen Tieren am Tag haben. Sie hat somit das Potential am Tag vorkommende intra- und interspezifische Interaktionen zu beeinflussen. Kapitel III weitet schließlich den Blickwinkel von der Individuen- hin zur Populationsebene. Es wurden experimentelle Populationen bestehend aus Rötelmäusen und Brandmäusen in großen Außengehegen etabliert, welche zuerst natürliche Lichtbedingungen und anschließend künstliche Beleuchtung bei Nacht erfuhren. Durch die Nutzung von UKW-Telemetriedaten konnte gezeigt werden, dass die Tiere unter natürlichen Lichtbedingungen vorwiegend tagaktiv waren. Dieser Unterschied in der Aktivität zwischen Tag und Nacht verschwand bei künstlicher Beleuchtung bei Nacht. Zusätzlich reduzierten Artgenossen die Überlappung ihrer Aktionsräume, ihre Nähe zueinander und die Synchronität ihrer Aktivitätszeiten. Risikobereitschaft beeinflusste die gezeigten Verhaltensveränderungen unter künstlicher Beleuchtung bei Nacht nicht. Die Resultate deuten darauf hin, dass künstliche Beleuchtung bei Nacht intraspezifische Interaktionen beeinflussen kann und somit potentiell Konsequenzen für die Fitness auf der Populationsebene haben kann. Zusammenfassend kann diese Doktorarbeit zeigen, dass künstliche Beleuchtung bei Nacht sowohl das Verhalten bei Nacht und bei Tag als auch intraspezifische Interaktionen von polyphasischen Kleinsäugern beeinflussen kann. Wie stark Unterschiede im Risikoverhalten von Individuen eine Rolle spielen, könnte von anderen Umweltfaktoren abhängen, welche mit der künstlichen Beleuchtung interagieren. Diese Arbeit bewirkt so hoffentlich eine Erweiterung des Blickwinkels, indem zukünftig die Rolle von Tierpersönlichkeiten im Umgang mit künstlicher Beleuchtung bei Nacht und die Effekte dieser Beleuchtung auf das Verhalten am Tag sowie tagaktive Arten berücksichtigt werden. KW - light pollution KW - human-induced rapid environmental change KW - urbanization KW - movement KW - activity KW - Lichtverschmutzung KW - anthropogene Umweltveränderungen KW - Urbanisation KW - Fortbewegung KW - Aktivität Y1 - 2021 ER - TY - JOUR A1 - Foster, Grace A1 - Poppenhäger, Katja T1 - Identifying interesting planetary systems for future X-ray observations JF - Astronomische Nachrichten = Astronomical notes N2 - X-ray observations of star-planet systems are important to grow our understanding of exoplanets; these observations allow for studies of photoevaporation of the exoplanetary atmosphere, and in some cases even estimations of the size of the outer planetary atmosphere. The German-Russian eROSITA instrument onboard the SRG (Spectrum Roentgen Gamma) mission is performing the first all-sky X-ray survey since the 1990s, and provides X-ray fluxes and spectra of exoplanet host stars over a much larger volume than was accessible before. Using new eROSITA data as well as archival data from XMM-Newton, Chandra, and ROSAT, we estimate mass-loss rates of exoplanets under an energy-limited escape scenario and identify several exoplanets with strong X-ray irradiation and expected mass loss that are amenable to follow-up observations at other wavelengths. We model sample spectra using a toy model of an exoplanetary atmosphere to predict what exoplanet transit observations with future X-ray missions such as Athena will look like and estimate the observable X-ray transmission spectrum for a typical hot Jupiter-type exoplanet. KW - planets and satellites KW - general KW - stars KW - activity KW - coronae KW - planetary systems KW - X-rays Y1 - 2022 U6 - https://doi.org/10.1002/asna.20220007 SN - 1521-3994 VL - 343 IS - 4 PB - Wiley-VCH CY - Berlin ER - TY - JOUR A1 - Dineva, Ekaterina A1 - Pearson, Jeniveve A1 - Ilyin, Ilya A1 - Verma, Meetu A1 - Diercke, Andrea A1 - Strassmeier, Klaus A1 - Denker, Carsten T1 - Characterization of chromospheric activity based on Sun-as-a-star spectral and disk-resolved activity indices JF - Astronomische Nachrichten = Astronomical notes N2 - The strong chromospheric absorption lines Ca ii H & K are tightly connected to stellar surface magnetic fields. Only for the Sun, spectral activity indices can be related to evolving magnetic features on the solar disk. The Solar Disk-Integrated (SDI) telescope feeds the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) of the Large Binocular Telescope (LBT) at Mt. Graham International Observatory, Arizona, U.S.A. We present high-resolution, high-fidelity spectra that were recorded on 184 & 82 days in 2018 & 2019 and derive the Ca ii H & K emission ratio, that is, the S-index. In addition, we compile excess brightness and area indices based on full-disk Ca ii K-line-core filtergrams of the Chromospheric Telescope (ChroTel) at Observatorio del Teide, Tenerife, Spain and full-disk ultraviolet (UV) 1600 angstrom images of the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). Thus, Sun-as-a-star spectral indices are related to their counterparts derived from resolved images of the solar chromosphere. All indices display signatures of rotational modulation, even during the very low magnetic activity in the minimum of Solar Cycle 24. Bringing together different types of activity indices has the potential to join disparate chromospheric datasets yielding a comprehensive description of chromospheric activity across many solar cycles. KW - astronomical databases KW - miscellaneous KW - methods KW - data analysis KW - activity KW - Sun KW - atmosphere KW - chromosphere KW - techniques KW - spectroscopic Y1 - 2022 U6 - https://doi.org/10.1002/asna.20223996 SN - 0004-6337 SN - 1521-3994 VL - 343 IS - 5 PB - Wiley-VCH CY - Weinheim ER -