Infrared spectral analys is and paleo-environment reconstruction on Mars

Connecting surface imaging and topography with IR spectral mineral identification provides better possibility for paleo-environment reconstruction. A project to compile a database of such indicators is started, the system’s background is outlined

Analysing high resolution digital Mars images using machine learning

The search for ephemeral liquid water on Mars is an ongoing activity. After the recession of the seasonal polar ice cap on Mars, small water ice patches may be left behind in shady places due to the low thermal conductivity of the Martian surface and atmosphere. During late spring and early summer, these patches may be exposed to direct sunlight and warm up rapidly enough for the liquid phase to emerge. To see the spatial and temporal occurrence of such ice patches, optical images should be searched for and checked. Previously a manual image analysis was conducted on 110 images from the southern hemisphere, captured by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter space mission. Out of these, 37 images were identified with smaller ice patches, which were distinguishable by their brightness, colour and strong connection to local topographic shading. In this study, a convolutional neural network (CNN) is applied to find further images with potential water ice patches in the latitude band between -40{\deg} and -60{\deg}, where the seasonal retreat of the polar ice cap happens. Previously analysed HiRISE images were used to train the model, where each image was split into hundreds of pieces (chunks), expanding the training dataset to 6240 images. A test run conducted on 38 new HiRISE images indicates that the program can generally recognise small bright patches, however further training might be needed for more precise identification. This further training has been conducted now, incorporating the results of the previous test run. To retrain the model, 18646 chunks were analysed and 48 additional epochs were ran. In the end the model produced a 94% accuracy in recognising ice, 58% of these images showed small enough ice patches on them. The rest of the images was covered by too much ice or showed CO2 ice sublimation in some places

Geomorphologic analysis of drainage networks on Mars

Altogether 327 valleys and their 314 cross-sectional profiles were analyzed on Mars, including width, depth, length, eroded volume, drainage and spatial density, as well as the network structure. According to this systematic analysis, five possible drainage network types were identified such as (a) small valleys, (b) integrated small valleys, (c) individual, medium-sized valleys, (d) unconfined, anastomosing outflow valleys, and (e) confined outflow valleys. Measuring their various morphometric parameters, these five networks differ from each other in terms of parameters of the eroded volume, drainage density and depth values. This classification is more detailed than those described in the literature previously and correlated to several numerical parameters for the first time. These different types were probably formed during different periods of the evolution of Mars, and sprung from differently localized water sources, and they could be correlated to similar fluvial network types from the Earth

Possibility for albedo estimation of exomoons: Why should we care about M dwarfs?

Occultation light curves of exomoons may give information on their albedo and hence indicate the presence of ice cover on the surface. Icy moons might have subsurface oceans thus these may potentially be habitable. The objective of our paper is to determine whether next generation telescopes will be capable of albedo estimations for icy exomoons using their occultation light curves. The success of the measurements depends on the depth of the moon's occultation in the light curve and on the sensitivity of the used instruments. We applied simple calculations for different stellar masses in the V and J photometric bands, and compared the flux drop caused by the moon's occultation and the estimated photon noise of next generation missions with 5 $\sigma$ confidence. We found that albedo estimation by this method is not feasible for moons of solar-like stars, but small M dwarfs are better candidates for such measurements. Our calculations in the J photometric band show that E-ELT MICADO's photon noise is just about 4 ppm greater than the flux difference caused by a 2 Earth-radii icy satellite in a circular orbit at the snowline of an 0.1 stellar mass star. However, considering only photon noise underestimates the real expected noise, because other noise sources, such as CCD read-out and dark signal become significant in the near infrared measurements. Hence we conclude that occultation measurements with next generation missions are far too challenging, even in the case of large, icy moons at the snowline of small M dwarfs. We also discuss the role of the parameters that were neglected in the calculations, e.g. inclination, eccentricity, orbiting direction of the moon. We predict that the first albedo estimations of exomoons will probably be made for large icy moons around the snowline of M4 -- M9 type main sequence stars.Comment: 13 pages, 6 figures, accepted for publication in A&

A marsi hidroszféra jellemzői

A Mars fejlődéstörténetének korai időszakából az elméleti modellek mellett többféle morfológiai és ásványtani nyom utal a globális hidroszféra létére. Az egykori globális rendszer a későbbiekben függőleges irányban ketté vagy rétegzetté vált, a felszín alatti és feletti térség elszigetelődött egymástól, és kommunikációjuk a H2O mozgását tekintve erősen csökkent. Időszakosan még ezt követően is „feléledt” a rendszer, de többnyire csak regionálisan és csak átmenetileg jelentek meg vízzel kapcsolatos kölcsönhatások és változások: helyi vízfeltörések, felszíni áramlás és tározódás, csapadékhullás, valamint vízzel kapcsolatos anyagszállítás és kémiai kiválások formájában. Ezek a periódusok térben korlátozva, időben egymástól elkülönülve, nem folyamatosan léteztek, amelyek nyomai az általánosan gyenge felszínalakulás révén tartósan fennmaradtak. Jelenleg nem egyértelmű, hogy ezeket a periódusokat tekinthetjük-e a hidroszféra rövid megjelenésének a bolygón, mivel nem mutatják a földi esetben jellemző globális kapcsolatrendszert – további elemzésük közelebb vihet egy bolygóméretű rendszer működésének jobb megértéséhez ilyen szempontból

Fluvial geomorphology of Mars: background to separate biogenic and abiogenic effects and to identify climate change related features

Biogenic effects might also influence the geomorphology of fluvial systems. An important issue in this aspect is the separation of abiogenic effects, what is quite difficult on the Earth as small level of bacterial influence is present almost at all locations. One possible solution would be the analysis of fluvial systems beyond the Earth. Here Martian fluvial structures are overviewed in this aspect, comparing the related effects and consequences on the two planets. Although our knowledge in this topic is not enough yet for firm conclusions, it is worth evaluating this question already. Based on the review presented here higher fluctuations of discharges, elevated influence of subsurface waters, and weaker bank stability is expected without biogenic effects. Beside these issues Martian systems also provide useful information on the connection between climate change and fluvial systems, as the range of climatic fluctuations were much larger on Mars than here on Earth

Deliquescence probability maps of Mars and key limiting factors using GCM model calculations

There may be a chance of small-scale ephemeral liquid water formation on present day Mars, even though the current climate does not support the existence of larger bodies of water. Through a process called deliquescence, hygroscopic salts can enter solution by absorbing water vapor directly from the atmosphere. Due to the absence of in-situ deliquescence experiments so far, the most reliable way to forecast deliquescence is through atmospherical modeling, however, the locations and times when salty liquid water could emerge are not yet well known. In this paper we present our results of likely brine formation on Mars, their proposed locations and seasons, as well as the possible limiting factors. For our calculations we used the data of Laboratoire de M\'et\'eorologie Dynamique Mars General Circulation Model version 5. The results show that from L$_s$ 35$^\circ$ - L$_s$ 160$^\circ$, between 9 PM and 11 PM there is a good chance for calcium perchlorate deliquescence above 30$^\circ$ N, while in this zone the ideal regions are concentrated mostly to Acidalia Planitia and Utopia Planitia between 1 AM and 3 AM. We found that in the Southern Hemisphere, between L$_s$ 195$^\circ$ and L$_s$ 320$^\circ$, there is a noticeable, but weaker band in the vicinity of 60$^\circ$ S, and both Argyre Planitia and Hellas Planitia show some chance for brine formation. According to our statistics the key limiting factor of deliquescence could be relative humidity in most cases. Our results suggest that during summer -- early fall seasons, there could be deliquescence in both hemispheres in specific areas from the late evening until the early morning hours. There are only few studies detailing the geological and temporal distribution of brine formation through deliquescence, thus this work could be used as a good guide for future landing site analysis or in choosing a specific location for further research.Comment: Accepted for publication in Icarus (arXiv version is Review 1, final version will be online soon on Icarus website