It's Gänseliesel day in Göttingen! Freshly minted PhD graduate Johannes Hölken attended the official ceremony at the Aula, has been picked up by us and ferried to the Gänseliesel fountain in the city center, and is about to bring the goose girl on the top of the fountain some flowers. Meanwhile, other carts around us are also interesting to look at!
#IMPRS #phd #Göttingen #germandoctoralhat #solarphysics #mpsgoettingen #unigoettingen
📄 Benchmarking CME Arrival Time and Impact: Progress on Metadata, Metri…
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Verbeke, C. et al. (2019) · Space Weather
Reads: 95 · Citations: 55
DOI: 10.1029/2018SW002046
🔗 https://ui.adsabs.harvard.edu/abs/2019SpWea..17....6V/abstract
#Astronomy #Astrophysics #SolarPhysics #CoronalMassEjectionsCmes #ModelValidation
Accurate forecasting of the arrival time and subsequent geomagnetic impacts of coronal mass ejections (CMEs) at Earth is an important objective for space weather forecasting agencies. Recently, the CME Arrival and Impact working team has made significant progress toward defining community-agreed metrics and validation methods to assess the current state of CME modeling capabilities. This will allow the community to quantify our current capabilities and track progress in models over time. First, it is crucial that the community focuses on the collection of the necessary metadata for transparency and reproducibility of results. Concerning CME arrival and impact we have identified six different metadata types: 3-D CME measurement, model description, model input, CME (non)arrival observation, model output data, and metrics and validation methods. Second, the working team has also identified a validation time period, where all events within the following two periods will be considered: 1 January 2011 to 31 December 2012 and January 2015 to 31 December 2015. Those two periods amount to a total of about 100 hit events at Earth and a large amount of misses. Considering a time period will remove any bias in selecting events and the event set will represent a sample set that will not be biased by user selection. Lastly, we have defined the basic metrics and skill scores that the CME Arrival and Impact working team will focus on.
📄 The Future of Solar System Exploration (2003-2013) -- Community Contr…
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Sykes, Mark V. et al. (2002) · The Future of Solar System Exploration (2003-2013) -- First Decadal Study contributions
Reads: 0 · Citation…
🔗 https://ui.adsabs.harvard.edu/abs/2002ASPC..272.....S/abstract
#Astronomy #Astrophysics #SolarPhysics #SolarSystemExploration #SpacePolicy
Between June 2001 and January 2002, planetary scientists from around the United States and other nations created 24 self-selected panels to discuss issues facing solar system exploration in 2003-2013 and how those issues should be addressed. Each panel generated a white paper, containing their conclusions and recommendations. These were forwarded to the National Research Council as community input in support of the Solar System Exploration Decadal Survey and comprise the chapters of this book.
📄 The Hinode (Solar-B) Mission: An Overview
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Kosugi, T. et al. (2007) · Solar Physics
Reads: 9 · Citations: 1641
DOI: 10.1007/s11207-007-9014-6
🔗 https://ui.adsabs.harvard.edu/abs/2007SoPh..243....3K/abstract
#Astronomy #Astrophysics #SolarPhysics #SolarOpticalTelescope #HinodeMission
The Hinode satellite (formerly Solar-B) of the Japan Aerospace Exploration Agency's Institute of Space and Astronautical Science (ISAS/JAXA) was successfully launched in September 2006. As the successor to the Yohkoh mission, it aims to understand how magnetic energy gets transferred from the photosphere to the upper atmosphere and results in explosive energy releases. Hinode is an observatory style mission, with all the instruments being designed and built to work together to address the science aims. There are three instruments onboard: the Solar Optical Telescope (SOT), the EUV Imaging Spectrometer (EIS), and the X-Ray Telescope (XRT). This paper provides an overview of the mission, detailing the satellite, the scientific payload, and operations. It will conclude with discussions on how the international science community can participate in the analysis of the mission data.
📄 Impact of near-degeneracy effects on linear rotational inversions for…
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Ahlborn, F. et al. (2025) · Astronomy and Astrophysics
Reads: 8138 · Citations: 1
DOI: 10.1051/0004-6361/202555537
🔗 https://ui.adsabs.harvard.edu/abs/2025A&A...704A.230A/abstract
#Astronomy #Astrophysics #SolarPhysics #Asteroseismology #StarsInteriors
Context.Accurate estimates of internal red giant rotation rates are crucial for constraining and improving current models of stellar rotation. Asteroseismic rotational inversions provide a means of estimating these internal rotation rates. Aims. In this work, we focus on the observed differences in the rotationally induced frequency shifts between prograde and retrograde modes. These effects have been overlooked in previous studies estimating internal rotation rates of red giants using inversions. We systematically study the limits of applicability of linear rotational inversions as a function of the evolution on the red giant branch and of the underlying rotation rates. Methods. We determine oscillation mode frequencies in the presence of rotation using the lowest-order perturbative approach and describe the differences between prograde and retrograde modes arising from the coupling of multiple mixed modes, also known as near-degeneracy effects. We computed synthetic rotational splittings, taking these near-degeneracy effects into account. We used red giant models with one solar mass, a large frequency separation between 16 and 9 μHz, and core rotation rates between 500 and 1500 nHz, covering the regime of observed parameters of Kepler red giant stars. Finally, we used these synthetic data to quantify the systematic errors in the internal rotation rates estimated by means of rotational inversions in the presence of near-degeneracy effects. Results. We show that the systematic errors in the estimated rotation rates introduced by near-degeneracy effects surpass the observational uncertainties for more evolved and faster-rotating stars. For a core rotation rate of 500 nHz, linear inversions remain applicable over the range of models considered here, while for a core rotation rate of 1000 nHz, systematic errors become significant below a large frequency separation of 13 μHz. Conclusions. The estimated rotation rates of some previously analysed red giants suffer from significant systematic errors that have not yet been accounted for. Nonetheless, reliable analyses with existing inversion methods are feasible for a number of red giants, and we expect there to be unexplored targets within the parameter ranges determined here. Finally, exploiting the observational potential of near-degeneracy effects is an important step towards obtaining more accurate estimates of internal red-giant rotation rates.
📄 The Spitzer Space Telescope Mission
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Werner, M. W. et al. (2004) · The Astrophysical Journal Supplement Series
Reads: 108 · Citations: 2799
DOI: 10.1086/422992
🔗 https://ui.adsabs.harvard.edu/abs/2004ApJS..154....1W/abstract
#Astronomy #Astrophysics #SolarPhysics #SpaceVehiclesInstruments #Telescopes
The Spitzer Space Telescope, NASA's Great Observatory for infrared astronomy, was launched 2003 August 25 and is returning excellent scientific data from its Earth-trailing solar orbit. Spitzer combines the intrinsic sensitivity achievable with a cryogenic telescope in space with the great imaging and spectroscopic power of modern detector arrays to provide the user community with huge gains in capability for exploration of the cosmos in the infrared. The observatory systems are largely performing as expected, and the projected cryogenic lifetime is in excess of 5 years. This paper summarizes the on-orbit scientific, technical, and operational performance of Spitzer. Subsequent papers in this special issue describe the Spitzer instruments in detail and highlight many of the exciting scientific results obtained during the first 6 months of the Spitzer mission.
📄 Differences between CME-driven storms and CIR-driven storms
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Borovsky, Joseph E. et al. (2006) · Journal of Geophysical Research (Space Physics)
Reads: 2 · Citations: 470
DOI: 10.1029/2005JA011447
🔗 https://ui.adsabs.harvard.edu/abs/2006JGRA..111.7S08B/abstract
#Astronomy #Astrophysics #SolarPhysics #MagnetosphericPhysicsMagneticStormsAndSubstorms7954 #I…
Twenty one differences between CME-driven geomagnetic storms and CIR-driven geomagnetic storms are tabulated. (CME-driven includes driving by CME sheaths, by magnetic clouds, and by ejecta; CIR-driven includes driving by the associated recurring high-speed streams.) These differences involve the bow shock, the magnetosheath, the radiation belts, the ring current, the aurora, the Earth's plasma sheet, magnetospheric convection, ULF pulsations, spacecraft charging in the magnetosphere, and the saturation of the polar cap potential. CME-driven storms are brief, have denser plasma sheets, have strong ring currents and Dst, have solar energetic particle events, and can produce great auroras and dangerous geomagnetically induced currents; CIR-driven storms are of longer duration, have hotter plasmas and stronger spacecraft charging, and produce high fluxes of relativistic electrons. Further, the magnetosphere is more likely to be preconditioned with dense plasmas prior to CIR-driven storms than it is prior to CME-driven storms. CME-driven storms pose more of a problem for Earth-based electrical systems; CIR-driven storms pose more of a problem for space-based assets.
📄 Modules for Experiments in Stellar Astrophysics (MESA)
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Paxton, Bill et al. (2011) · The Astrophysical Journal Supplement Series
Reads: 482 · Citations: 4139
DOI: 10.1088/0067-0049/192/1/3
🔗 https://ui.adsabs.harvard.edu/abs/2011ApJS..192....3P/abstract
#Astronomy #Astrophysics #SolarPhysics #MethodsNumerical #StarsEvolution
Stellar physics and evolution calculations enable a broad range of research in astrophysics. Modules for Experiments in Stellar Astrophysics (MESA) is a suite of open source, robust, efficient, thread-safe libraries for a wide range of applications in computational stellar astrophysics. A one-dimensional stellar evolution module, MESAstar, combines many of the numerical and physics modules for simulations of a wide range of stellar evolution scenarios ranging from very low mass to massive stars, including advanced evolutionary phases. MESAstar solves the fully coupled structure and composition equations simultaneously. It uses adaptive mesh refinement and sophisticated timestep controls, and supports shared memory parallelism based on OpenMP. State-of-the-art modules provide equation of state, opacity, nuclear reaction rates, element diffusion data, and atmosphere boundary conditions. Each module is constructed as a separate Fortran 95 library with its own explicitly defined public interface to facilitate independent development. Several detailed examples indicate the extensive verification and testing that is continuously performed and demonstrate the wide range of capabilities that MESA possesses. These examples include evolutionary tracks of very low mass stars, brown dwarfs, and gas giant planets to very old ages; the complete evolutionary track of a 1 M <SUB>sun</SUB> star from the pre-main sequence (PMS) to a cooling white dwarf; the solar sound speed profile; the evolution of intermediate-mass stars through the He-core burning phase and thermal pulses on the He-shell burning asymptotic giant branch phase; the interior structure of slowly pulsating B Stars and Beta Cepheids; the complete evolutionary tracks of massive stars from the PMS to the onset of core collapse; mass transfer from stars undergoing Roche lobe overflow; and the evolution of helium accretion onto a neutron star. MESA can be downloaded from the project Web site (<A href="http://mesa.sourceforge.net/">http://mesa.sourceforge.net/</A>).
📄 Field testing and evaluation of a solar-blind UV communication link f…
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Shaw, Gary A. et al. (2004) · Unattended/Unmanned Ground, Ocean, and Air Sensor Technologies and Applications VI
Reads: 0 · Citations: 13
…
🔗 https://ui.adsabs.harvard.edu/abs/2004SPIE.5417..250S/abstract
Non-line-of-sight ultraviolet (UV) communication technology to support unattended ground sensor communication is described. The concept exploits atmospheric scattering of ultraviolet light to achieve modest data rates under non line-of-sight (ground-to-ground) and obstructed line-of-sight (foliage penetration) conditions. The transmitter consists of a digitally modulated UV source and the receiver employs a sharp cutoff solar-blind absorption filter coupled to a channel photomultiplier module. Prototype semiconductor UV sources with center wavelengths in the solar blind region (<280nm) already offer higher power efficiency than lasers, along with advantages in size, simplicity, and flexibility relative to both lasers and traditional mercury sources. Once commercialized, semiconductor UV sources will also offer significant cost savings over traditional gas-discharge and solid-state UV sources. In this paper, the temporal and spectral properties of a number of prototype semiconductor UV sources are presented and compared to a low-pressure mercury vapor source. Efficient modulation and data coding methods compatible with the output characteristics of both sources are discussed, and measurements from recent test bed experiments are presented.
Phil 📸
IMPRS Solar System School
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