Structural analysis of the comet 45P/Honda based on isophote modeling

The work focuses on using the isophote method to construct a 45P/Honda comet model. At the same time, important problems were solved for modeling the physical surface of a comet and studying the structure of the cometary nucleus. This is due to the fact that, on the basis of modern studies of meteoroids, complex internal processes and dynamic phenomena on their surface have been discovered. The study of comet nuclei is of great importance, since, according to the theory of their formation, they were formed from the matter of the protoplanetary disk. Thus, modeling and analysis of the structure of various comets make it possible to create a more accurate theory of their evolution. This made it possible to evaluate the structural parameters more accurately and reliably. This allowed for the evaluation of the structural parameters more accurately and reliably. Isophotes of the nucleus, coma and tail of comet 45P/Honda were determined. Depending on the point where the comet is located on the trajectory of its orbit, one can see structural changes in the comet’s brightness from the nucleus to the peripheral region. Near the cometary nucleus, the isophotes are circular in shape. If in the center of the model the isophotes have a shape close to narrow rings, then elongations in the direction of the cometary tail and thickening of their structure appear towards the peripheral regions. Large and small tail rays can be distinguished, and the nucleus is well marked. In the future, the author’s method for modeling isophotes, developed in this work, will allow studying the structure of various cometary objects, and, based on the results, determine the degree of comet activity. On the other hand, about the development of the theory of dynamic processes and the evolution of the Solar system, one can use the data on changes in cometary activity in the process of its movement around the Sun.

Sun Planet Interactions Digital Environment on Request (VESPASPIDER) for Europlanet RI H2024: status after 2 years

<p>The H2020 Europlanet-2020 programme, which ended on Aug 31<sup>st</sup>, 2019, included an activity called PSWS (Planetary Space Weather Services), which provided 12 services distributed over four different domains (A. Prediction, B. Detection, C. Modelling, D. Alerts) and accessed through the PSWS portal (http://planetaryspaceweather-europlanet.irap.omp.eu/):</p> <p>A1. 1D MHD Solar Wind Prediction Tool – HELIOPROPA,</p> <p>A2. Propagation Tool,</p> <p>A3. Meteor showers,</p> <p>A4. Cometary tail crossings – TAILCATCHER,</p> <p>B1. Lunar impacts – ALFIE,</p> <p>B2. Giant planet fireballs – DeTeCt3.1,</p> <p>B3. Cometary tails – WINDSOCKS,</p> <p>C1. Earth, Mars, Venus, Jupiter coupling- TRANSPLANET,</p> <p>C2. Mars radiation environment – RADMAREE,</p> <p>C3. Giant planet magnetodiscs – MAGNETODISC,</p> <p>C4. Jupiter’s thermosphere, D. Alerts.</p> <p>In the framework of the ongoing Europlanet-2024 programme, SPIDER will extend PSWS domains (A. Prediction, C. Modelling, E. Databases) services and give the European planetary scientists, space agencies and industries access to 6 unique, publicly available and sophisticated services in order to model planetary environments and solar wind interactions through the deployment of a dedicated run on request infrastructure and associated databases.</p> <p>C5. A service for runs on request of models of Jupiter’s moon exospheres as well as the exosphere of Mercury,</p> <p>C6. A service to connect the open-source Spacecraft-Plasma Interaction Software (SPIS) software with models of space environments in order to compute the effect of spacecraft potential on scientific instruments onboard space missions. Pre-configured simulations will be made for Bepi-Colombo and JUICE missions,</p> <p>C7. A service for runs on request of particle tracing models in planetary magnetospheres,</p> <p>E1. A database of the high-energy particle flux proxy at Mars, Venus and comet 67P using background counts observed in the data obtained by the plasma instruments onboard Mars Express (operational from 2003), Venus Express (2006–2014), and Rosetta (2014–2015);</p> <p>E2. A simulation database for Mercury and Jupiter’s moons magnetospheres and link them with prediction of the solar wind parameters from Europlanet-RI H2020 PSWS services.</p> <p>A1. An extension of the Europlanet-RI H2020 PSWS Heliopropa service in order to ingest new observations from Solar missions like the ESA Solar Orbiter or NASA Solar Parker Probe missions and use them as input parameters for solar wind prediction;</p> <p>The developments performed during the second year of the project will be discussed in the presentation.</p> <p>The Europlanet 2020 Research Infrastructure project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 654208.</p>

Effects of radiation pressure on the evaporative wind of HD 209458b

ABSTRACT The role of radiation pressure in shaping exoplanet photoevaporation remains a topic of contention. Radiation pressure from the exoplanet’s host star has been proposed as a mechanism to drive the escaping atmosphere into a ‘cometary’ tail and explain the high velocities observed in systems where mass-loss is occurring. In this paper, we present results from high-resolution 3D hydrodynamic simulations of a planet similar to HD 209458b. We self-consistently launch a wind flowing outwards from the planet by calculating the ionization and heating resulting from incident high-energy radiation, and account for radiation pressure. We first present a simplified calculation, setting a limit on the Lyman-α flux required to drive the photoevaporated planetary material to larger radii and line-of-sight velocities. We then present the results of our simulations, which confirm the limits determined by our analytic calculation. We thus demonstrate that, within the limits of our hydrodynamic simulation and for the Lyman-α fluxes expected for HD 209458, radiation pressure is unlikely to significantly affect photoevaporative winds or to explain the high velocities at which wind material is observed, though further possibilities remain to be investigated.

Determination of some characteristics of comet’s gases by photometry method for comet Hyakutake

The present paper focuses on the study of some characteristics ofcomets ions by photometry method which represent by CCD camerawhich it provide seeing these images in a graded light. From 0-255when Zero (low a light intensity) and 255 (highlight intensity). Thesedifferences of photonic intensity can be giving us a curve whichappear from any line of this image.From these equations the focus is concentrating on determine thetemperature distribution, velocity distribution, and intensity numberdistribution which is give number of particles per unit volume.The results explained the interaction near the cometary nucleuswhich is mainly affected by the new ions added to the density of thesolar wind, the average molecular weight increase and result in manyunique characteristics of the cometary tail.

The Cosmic Skidmark: witnessing galaxy transformation at z = 0.19

We present an early-look analysis of the “Cosmic Skidmark”. Discovered following visual inspection of the Geach, Murphy & Bower (2011) SDSS Stripe 82 cluster catalogue generated by ORCA (an automated cluster algorithm searching for red-sequences; Murphy, Geach & Bower 2012), this z = 0.19 1.4L⋆ galaxy appears to have been caught in the rare act of transformation while accreting onto an estimated 1013–1014h−1 M⊙-mass galaxy group. SDSS spectroscopy reveals clear signatures of star formation whilst deep optical imaging reveals a pronounced 50 kpc cometary tail. Pending completion of our ALMA Cycle 2 and IFU observations, we show here preliminary analysis of this target.

Probing the Solar Magnetic Field with a Sun-Grazing Comet

On 15 and 16 December 2011, Sun-grazing comet C/2011 W3 (Lovejoy) passed deep within the solar corona, effectively probing a region that has never been visited by spacecraft. Imaged from multiple perspectives, extreme ultraviolet observations of Lovejoy's tail showed substantial changes in direction, intensity, magnitude, and persistence. To understand this unique signature, we combined a state-of-the-art magnetohydrodynamic model of the solar corona and a model for the motion of emitting cometary tail ions in an embedded plasma. The observed tail motions reveal the inhomogeneous magnetic field of the solar corona. We show how these motions constrain field and plasma properties along the trajectory, and how they can be used to meaningfully distinguish between two classes of magnetic field models.