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X-WR-CALNAME:Osservatorio Astrofisico di Catania
X-ORIGINAL-URL:https://www.oact.inaf.it
X-WR-CALDESC:Eventi per Osservatorio Astrofisico di Catania
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DTSTART:20230101T000000
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BEGIN:VEVENT
DTSTART;TZID=UTC:20260122T110000
DTEND;TZID=UTC:20260122T120000
DTSTAMP:20260418T092026
CREATED:20260115T110917Z
LAST-MODIFIED:20260120T171121Z
UID:19332-1769079600-1769083200@www.oact.inaf.it
SUMMARY:Magnetic activity nesting on the Sun and low-mass stars: Results from nearly continuous monitoring of solar active nests with ESA’s Solar Orbiter
DESCRIPTION:Recording: https://www.oact.inaf.it/seminars/ \nDATE: Thursday\, January 22\, 11:30 a.m. \nORGANIZER: INAF-OACT \nLOCATION: AULA OVEST (INAF-OACT) + remote \nLink for the remote audience:https://meet.google.com/wvf-uwxo-oyj \nSPEAKER: Adam Finley (ESA Noordwijk) \nABSTRACT:The magnetic activity of low-mass stars\, driven by the interplay of convection and rotation in their interiors\, is fundamental to their evolution and significantly affects the search for habitable exoplanets. Magnetic activity manifests at the surface as “spots” (or active regions) that influence the circumstellar environment through energetic radiation and eruptive events (flares and coronal mass-ejections\, collectively termed “space weather”). The Sun exhibits a well-known 11-year activity cycle where spot emergence drifts from mid to low latitudes. However\, one puzzling feature of the solar dynamo is the repeated emergence of spots in close proximity\, which leads to long-lived sources of magnetic activity known as active nests. Nesting is observed on other low-mass stars\, suggesting it is an innate\, universal feature of stellar dynamos. It is theorized that non-axisymmetries in the generation and storage of the magnetic field preference the emergence of spots at specific latitudes and longitudes\, leading to nesting. This phenomenon has consequences for predicting space weather near Earth and understanding the secular evolution of exoplanetary atmospheres. Studies of solar active nests have been limited by our single viewpoint from Earth. But with ESA’s Solar Orbiter now monitoring the Sun’s far-side for several months each year\, multi-viewpoint observations provide a pathway to study the formation and evolution of active nests. So far we have identified an active nest in 2022 that was responsible for 50–70% of all solar flares across the entire solar surface over five months (a prolific flare factory). In addition\, we saw a dramatic intensification of solar flare activity in 2024 following the collision of two active nests. These continuous\, multi-viewpoint observations strengthen the connection between solar activity and the nesting observed on other low-mass stars\, a link that will be further explored with ESA’s PLATO mission. \n  \nA few rules:— before joining\, make sure you are using your institutional inaf.it account if you have one (otherwise we will grant you permission to join)— please do not forget to mute your microphone and switch off your webcam when access the virtual room— for questions leave a message in the chat\, the answers at the end of the webinar— the seminar will be recorded\, so if you are interested in it\, please contact us to get the link to the registration.
URL:https://www.oact.inaf.it/event/magnetic-activity-nesting-on-the-sun-and-low-mass-stars-results-from-nearly-continuous-monitoring-of-solar-active-nests-with-esas-solar-orbiter/
LOCATION:Sede A. Riccò\, Via Santa Sofia 78\, Catania
CATEGORIES:Eventi & Seminari
ATTACH;FMTTYPE=image/jpeg:https://www.oact.inaf.it/wp-content/uploads/2026/01/Finley_titleslide.jpg
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BEGIN:VEVENT
DTSTART;TZID=UTC:20241004T110000
DTEND;TZID=UTC:20241004T120000
DTSTAMP:20260418T092027
CREATED:20241001T090846Z
LAST-MODIFIED:20241001T090849Z
UID:16879-1728039600-1728043200@www.oact.inaf.it
SUMMARY:Unraveling Space Weathering on Planetary and Astrophysical Surfaces
DESCRIPTION:Recording: https://www.oact.inaf.it/seminars/ \nDATE:  Friday\, October 4\, 11:00 a.m. \nORGANIZER: INAF-OACT \nLOCATION: AULA OVEST (INAF-OACT) + remote \nLink for the remote audience:https://meet.google.com/wvf-uwxo-oyj \nSPEAKER: Prof. Thomas M. Orlando (School of Chemistry and Biochemistry and School of Physics\, Georgia Institute of Technology\, Atlanta\, GA\, USA) \nABSTRACT:It is well known that the interaction of energetic ions\, electrons and photons with surfaces and interfaces leads to non-thermal desorption via a process typically referred to as desorption induced by electronic transitions (DIET).  When DIET involves either electrons or photons\, these processes are generally referred to as electron-stimulated desorption and photon-stimulated desorption (PSD)\, respectively.  Recent attention has focused on understanding the role of non-thermal “space weathering” in the processing of interstellar grains and ices.Specifically\, there is deep interest in understanding the radiation processing of carbon grains in the solar nebula and unraveling the H2O formation mechanisms in solar nebula and planetary systems\, including the Moon. Using graphite grains\, the VUV photon-simulated oxidation of carbon grains via reactive scattering of water fragments produced by dissociative electron attachment at the buried interface was examined. The results suggested that VUV PSD at the buried water:carbon grain interface may help control the carbon inventory during planet formation. The inverse process\, (i.e\, the formation of water) may happen on metal-oxide samples such as mineral grains and lunar regolith samples\, that contain or are terminated by hydroxyl groups. Solar wind spaceweathering experiments of several Apollo lunar samples demonstrated that thermally activated recombinative desorption (RD) can be H2O sources [2\,3] and that electron-stimulated reactive scattering to produce water may also be occurring\, especially when the Moon is in the magnetopause[4].  RD can occur on a diurnal basis on the Moon and is prevalentduring meteoroid impacts. The latter is simulated by laser irradiation studies followed by state and velocity resolved detection of the produced water.  Finally\, evidence of space weathering and surface alteration has also been revealed using spatially resolved\, high-resolution nanoscale Fourier transform infrared imaging/spectroscopy correlated with photoluminescence (PL) on Apollo samples with different origins and history. \n[1]  J. Shi\, G. A. Greives\, and T. M. Orlando\, Astrophys. J 80(1) 24 (2015).[2] B. M. Jones\, et. al\, Geophys. Res. Lett.\, 45\, (2018) 10\,959–10\,967[3] B. M. Jones\, et. al\, Astrophys. J. Lett.\, 891 (2020) L43[4] 7. S. Li\, A. R. Poppe\, T. M. Orlando\, B. M. Jones\, O. J. Tucker\, W. M. Farrell\, and A. R. Hendrix\,”\, Nat. Astron. (2023) \n  \nA few rules:— in case of large in-person attendance\, attendees may be asked to wear a face mask— before joining\, make sure you are using your institutional inaf.it account if you have one (otherwise we will grant you permission to join)— please do not forget to mute your microphone and switch off your webcam when access the virtual room— for questions leave a message in the chat\, the answers at the end of the webinar— the seminar will be recorded\, so if you are interested in it\, please contact us to get the link to the registration.
URL:https://www.oact.inaf.it/event/unraveling-space-weathering-on-planetary-and-astrophysical-surfaces/
LOCATION:Sede A. Riccò\, Via Santa Sofia 78\, Catania
CATEGORIES:Eventi & Seminari
ATTACH;FMTTYPE=image/jpeg:https://www.oact.inaf.it/wp-content/uploads/2024/10/OrlandoCataniaSlide.jpg
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BEGIN:VEVENT
DTSTART;TZID=UTC:20231206T113000
DTEND;TZID=UTC:20231206T123000
DTSTAMP:20260418T092027
CREATED:20231130T090026Z
LAST-MODIFIED:20231205T183935Z
UID:15074-1701862200-1701865800@www.oact.inaf.it
SUMMARY:Space-Weathering on Primitive Asteroids
DESCRIPTION:Recording: https://www.oact.inaf.it/seminars/ \nDATE:  Wednesday\, December 6\, 11:30 a.m. \nORGANIZER: INAF OACT \nLOCATION: AULA OVEST (INAF-OACT) + remote \nLink for the remote audience:https://meet.google.com/wvf-uwxo-oyj \nSPEAKER: Dr. Stefano Rubino (INAF-IAPS) \nABSTRACT:Studying small bodies in our solar system is fundamental for understanding its youth and evolution. These small “primitive” bodies are “undifferentiated” (they did not undergo phase density separation\, irreversibly altering their mineralogy). They have evolved little since their creation\, spurring a composition relatively close to the primordial proto-planetary disk. However\, other processes\, such as thermal alteration\, aqueous alteration\, shocks\, or space-weathering\, can affect these bodies’ surfaces. This issue is because remote-sensed data acquired while studying these bodies target these surfaces. If these surfaces have been altered\, they can induce a particular bias in the study of the composition of these small bodies. Therefore\, it is paramount to understand the processes affecting the surface of primitive asteroids to assess their composition correctly.There are several ways to study the surface of primitive asteroids\, such as remotely\, from the Earth or a satellite orbiting the body of interest\, by acquiring spectroscopic data (gaining access to surface chemical and mineralogical composition). It is also possible to study these bodies in a laboratory environment by working on analogous materials\, such as certain classes of “primitive” meteorites (carbonaceous chondrites)\, on terrestrial analogs (simpler to study than meteorites but less closely related to extraterrestrial materials)\, or directly on extraterrestrial materials brought back by sample return missions.In this work\, we replicate the effects of space weathering (SpWe) on the surface of primitive asteroids in a laboratory environment. More specifically\, we focus on the effects of solar wind\, the dominant SpWe process on “young” surfaces of the solar system. We have chosen three terrestrial minerals analogous to a “primitive” surface – three hydrated minerals (two serpentines and one saponite) – of which we have produced several pellets which have been bombarded using He and Ar ions\, to investigate the effects of two different solar wind. In doing so\, we made analogous materials of weathered primitive surface matter.These analogs were then characterized by infrared spectroscopy\, from the visible to the far-infrared range\, to study chemical changes prompted by ion bombardment. This was done by investigating how certain spectroscopic features – characteristic of hydrated silicates – changed upon ion bombardment. We detected several effects\, such as darkening in the visible range\, visible slope reddening and bluing\, and a systematic shift towards longer wavelength affecting the position of several spectroscopic features.This spectroscopic characterization was followed by a study at a smaller scale using electron microscopy. We first characterized the surface of our weathered analogs using scanning electron microscopy. Then\, we investigated the morphological and physicochemical changes in the bombarded layer\, at a nanometer scale using transmission electron microscopy. Strong vesiculation effects of various kinds were identified in the ion-bombarded amorphized layers\, textural changes\, and some elemental concentration evolution (such as the loss of oxygen in the utmost top surfaces\, preferential amorphization of magnesium\, etc.). The coupling between these two techniques\, IR spectroscopy\, and electron microscopy acting at different scales\, has allowed for a better understanding of SpWe effects on primitive bodies and will be able to support current and future studies of primitive bodies\, whether they are carried out remotely or in a laboratory environment on returned samples. \n  \n  \nA few rules:— in case of large in-person attendance\, attendees may be asked to wear a face mask— before joining\, make sure you are using your institutional inaf.it account if you have one (otherwise we will grant you permission to join)— please do not forget to mute your microphone and switch off your webcam when access the virtual room— for questions leave a message in the chat\, the answers at the end of the webinar— the seminar will be recorded\, so if you are interested in it\, please contact us to get the link to the registration.
URL:https://www.oact.inaf.it/event/space-weathering-on-primitive-asteroids/
LOCATION:Sede A. Riccò\, Via Santa Sofia 78\, Catania
CATEGORIES:Eventi & Seminari
ATTACH;FMTTYPE=image/jpeg:https://www.oact.inaf.it/wp-content/uploads/2023/11/Rubino_locandina_6.12.23jpg.jpg
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