M. Hofmann
A5048489329- Astro and Planetary Science
- Planetary Science and Exploration
- Isotope Analysis in Ecology
- Geology and Paleoclimatology Research
- Dementia and Cognitive Impairment Research
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Alzheimer's disease research and treatments
- Landslides and related hazards
- Nuclear Physics and Applications
- Cryospheric studies and observations
- Schizophrenia research and treatment
- Tryptophan and brain disorders
- AI-based Problem Solving and Planning
- 3D Surveying and Cultural Heritage
- Astronomical and nuclear sciences
- Parkinson's Disease Mechanisms and Treatments
- Cholinesterase and Neurodegenerative Diseases
- Advanced Measurement and Metrology Techniques
- Augmented Reality Applications
- Geotechnical and Geomechanical Engineering
- Spacecraft and Cryogenic Technologies
- Memory and Neural Mechanisms
- Ecology, Conservation, and Geographical Studies
- Speech and dialogue systems
Kantonsspital Baden
2022
Hasomed (Germany)
2017-2020
Max Planck Institute for Solar System Research
2014-2018
Max Planck Society
2014-2017
University of Trento
2017
John Wiley & Sons (United States)
2015
Charles River Laboratories (Netherlands)
2015
Fraunhofer Society
2008-2009
University of Zurich
2003
Technical University of Munich
2002
During its 2 yr mission around comet 67P/Churyumov–Gerasimenko, ESA's Rosetta spacecraft had the unique opportunity to follow closely a in most active part of orbit. Many studies have presented typical features associated with activity nucleus, such as localized dust and gas jets. Here, we report on series more energetic transient events observed during 3 months surrounding comet's perihelion passage 2015 August. We detected characterized 34 outbursts cameras, one every 2.4 nucleus...
Dust jets, i.e. fuzzy collimated streams of cometary material arising from the nucleus, have been observed in-situ on all comets since Giotto mission flew by comet 1P/Halley in 1986. Yet their formation mechanism remains unknown. Several solutions proposed, localized physical mechanisms surface/sub-surface (see review Belton (2010)) to purely dynamical processes involving focusing gas flows local topography (Crifo et al. 2002). While latter seems be responsible for larger features, high...
We collect observational evidence that supports the scheme of mass transfer on nucleus comet 67P/Churyumov-Gerasimenko. The obliquity rotation axis 67P causes strong seasonal variations. During perihelion southern hemisphere is four times more active than north. Northern territories are widely covered by granular material indicates back fall originating from south. Decimetre sized chunks contain water ice and their trajectories influenced an anti-solar force instigated sublimation. OSIRIS...
Rosetta observes sublimating surface ices Comets are “dirty snowballs” made of ice and dust, but they dark because the sublimates away, leaving some dust behind on surface. The spacecraft has provided a close-up view comet 67P/Churyumov-Gerasimenko as it passes through its closest point to Sun (see Perspective by Dello Russo). Filacchione et al. detected spectral signature solid CO 2 (dry ice) in small patches nucleus emerged from local winter. By modeling how sublimates, constrain...
Abstract The Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) experiment onboard the Rosetta spacecraft currently orbiting comet 67P/Churyumov‐Gerasimenko has yielded unprecedented views of a comet's nucleus. We present here first ever observations meter‐scale fractures on surface comet. Some these form polygonal networks. an initial assessment their morphology, topology, regional distribution. Fractures are ubiquitous Furthermore, they occur in various settings show...
Context. OSIRIS, the scientific imaging system onboard ESA Rosetta spacecraft, has been nucleus of comet 67P/Churyumov-Gerasimenko and its dust gas environment since March 2014. The images serve different goals, from morphology composition studies surface, to motion trajectories grains, general structure coma, intensity jets, distribution, mass loss, production rates.
The Rosetta spacecraft spent ~2 years orbiting comet 67P/Churyumov-Gerasimenko, most of it at distances that allowed surface characterization and monitoring submeter scales. From December 2014 to June 2016, numerous localized changes were observed, which we attribute cometary-specific weathering, erosion, transient events driven by exposure sunlight other processes. While the suggest compositional or physical heterogeneity, their scale has not resulted in substantial alterations comet's...
On 2016 Feb 19, nine Rosetta instruments serendipitously observed an outburst of gas and dust from the nucleus comet 67P/Churyumov-Gerasimenko. Among these were cameras spectrometers ranging UV over visible to microwave wavelengths, in situ gas, plasma instruments, one collector. At 09:40 a cloud developed at edge image shadowed region nucleus. Over next two hours recorded signature that significantly exceeded background. The enhancement ranged 50 per cent neutral density factors >100...
We present observations of sunset jets on comet 67P/Churyumov-Gerasimenko by Rosetta/OSIRIS camera. In late April 2015, when the was at a heliocentric distance ~1.8 AU, clusters dust that originated in Ma'at region comet's small lobe were identified from multipleimages and apparently sustained for about an hour beyond local sunset. Emanating shadowed nucleus, these became visible solar illumination their apparent sources up to only few tens meters above nucleus surface. investigate...
We present OSIRIS/NAC observations of decimetre-sized, likely ice-containing aggregates ejected from a confined region on the surface comet 67P/Churyumov-Gerasimenko. The images were obtained in January 2016 when was at 2 AU Sun out-bound perihelion. measure acceleration individual through two-hour image series. Approximately 50% are accelerated away nucleus, and towards it, likewise either horizontal direction. accelerations up to one order magnitude stronger than local gravity, most simply...
On 3 July 2016, several instruments on board ESA's Rosetta spacecraft detected signs of an outburst event comet 67P, at a heliocentric distance 3.32 AU from the sun, outbound perihelion. We here report inferred properties ejected dust and surface change site outburst. The activity coincided with local sunrise continued over time interval 14 - 68 minutes. It left 10m-sized icy patch surface. material comprised refractory grains hundred microns in size, sub-micron-sized water ice grains. high...
Context. Dust deposits or dust cover are a prevalent morphology in the northern hemi-nucleus of comet 67P/Churyumov-Gerasimenko (67P). The evolution was captured by OSIRIS camera system onboard Rosetta spacecraft having escorted for over two years. observations shed light on fundamental role cometary activity shaping and transforming surface morphology.
The OSIRIS (optical, spectroscopic and infrared remote imaging system) instrument on board the ESA Rosetta spacecraft collected data of 67P/Churyumov–Gerasimenko for over 2 yr. consists two cameras, a Narrow Angle Camera Wide Camera. For specific sequences related to observation dust aggregates in 67P's coma, cameras were operating simultaneously. are mounted 0.7 m apart from each other, as result this baseline yields parallax shift apparent particle trails analysed images directly...
Aims.We carried out an investigation of the surface variegation comet 67P/Churyumov-Gerasimenko, detection regions showing activity, determination active and inactive with spectral methods, fallback material.
By using the imagery acquired by Optical, Spectroscopic, and Infrared Remote Imaging System Wide-Angle Camera (OSIRIS WAC), we prepare a high-resolution morphological map of Rosetta Sais final landing site, characterized an outcropping consolidated terrain unit, coarse boulder deposit fine particle deposit. Thanks to 0.014 m resolution images, derive pebbles/boulders size-frequency distribution (SFD) area in size range 0.07–0.70 m. Sais' SFD is best fitted with two-segment differential power...
We perform a thermo-physical analysis on water activity of comet 67P/Churyumov-Gerasimenko (67P). The sublimation is assumed to occur from beneath global, desiccated dust mantle over the irregular-shaped nucleus. concept two thermal models, recipe model formulation and strategy application 67P are described. For an accurate efficient evaluation energy input by insolation self-heating nucleus, Landscape data base devised based polyhedral shape models apply investigate impact certain...
We present a statistical analysis of the distribution large-scale topographic features on comet 67P/Churyumov–Gerasimenko. observe that cumulative cliff height across surface follows power law with slope equal to −1.69 ± 0.02. When this is studied independently for each region, we find good correlation between and orbital erosion rate surface. For instance, Northern hemisphere topography dominated by structures 100 m scale, while Southern topography, illuminated at perihelion, 10 scale...
Because of the diurnal thermal cycle and irregular shape nucleus, gas outflow comet 67P/Churyumov–Gerasimenko could be highly anisotropic as indicated by colliminated dust jet structures on sunlit side. Based OSIRIS imaging observations outgassing effect, a simple model surface sublimation can constructed taking into account dependence solar insolation. With preliminary information time variability global production rate, sequence coma models generated at different epochs before after...
To report the outcomes of active surveillance (AS) for low-risk prostate cancer (PCa) in a single-center cohort.This is prospective, single-center, observational study. The cohort included all patients who underwent AS PCa between December 1999 and 2020 at our institution. Follow-up appointments (FU) ended February 2021.A total 413 men were enrolled study, 391 had least one FU. Of those followed up, 267 diagnosed by transrectal ultrasound (TRUS)-guided biopsy (T1c: 68.3%), while 124 after...