Strong gravitational microlensing (GM) events provide us a possibility to determine both the parameters of microlensed source and microlens. GM can be an important clue to understand the nature of dark matter on comparably small spatial and mass scales (i.e. substructure), especially when speaking about the combination of astrometrical and photometrical data about high amplification microlensing events (HAME). In the same time, fitting of HAME lightcurves of microlensed sources is quite time-consuming process. That is why we test here the possibility to apply the statistical machine learning techniques to determine the source and microlens parameters for the set of HAME lightcurves, using the simulated set of amplification curves of sources microlensed by point masses and clumps of DM with various density profiles.

Compressive Sensing is an emerging technology for data compression and simultaneous data acquisition. This is an enabling technique for significant reduction in data bandwidth, and transmission power and hence, can greatly benefit space-flight instruments. We apply this process to detect exoplanets via gravitational microlensing. We experiment with various impact parameters that describe microlensing curves to determine the effectiveness and uncertainty caused by Compressive Sensing. Finally, we describe implications for space-flight missions.

Gravitational microlensing has a unique sensitivity to exoplanets at outside of the snow-line with masses down to the Earth-mass. Because of the rarity and short timescale of the planetary signal, the survey groups, MOA-II in New Zealand and OGLE-IV in Chile carry out the wide field survey observation towards the galactic bulge to issue alerts in real time. Then telescopes of the follow-up groups conduct high cadence follow-up observation to get dense sampling of the short planetary signal. Recent high cadence survey observations by MOA-II and OGLE-IV have started to find exoplanets without follow-up observation systematically. This is a transition to the next generation 24-hour high cadence survey network which can reveal the mass function of exoplanets down to Earth-mass outside of the snow-line. The Wide Field Infrared Survey Telescope (WFIRST) is the highest ranked recommendation for a large space mission in the recent New Worlds, New Horizons (NWNH) in Astronomy and Astrophysics 2010 Decadal Survey. Exoplanet microlensing program is one of the primary science of WFIRST. WFIRST will find about 2,000 bound planets and 1,000 unbound planets by the high precision continuous survey with 15 min. cadence. WFIRST can complete the statistical census of planetary systems in the Galaxy, from the outer habitable zone to gravitationally unbound planets – a discovery space inaccessible to other exoplanet detection techniques.

Microlensing has proven to be a valuable tool to search for extrasolar planets of Jovian- to Super-Earth-mass planets at orbits of a few AU. Since planetary signals are of very short duration, an intense and continuous monitoring is required. This is achieved by ground-based networks of telescopes (PLANET/RoboNET, μFUN) following up targets, which are identified as microlensing events by single dedicated telescopes (OGLE, MOA). Microlensing has led to four already published detections of extrasolar planets, one of them being OGLE 2005-BLG-390Lb, a planet of only ∼5.5 M⊕ orbiting its M-dwarf host star at ∼2.6 AU. Very recent observations (May–September 2007) provided four more planetary candidates, still under study, that will double the number of detections. For non-planetary microlensing events observed from 1995 to 2006 we compute detection efficiency diagrams, which can then be used to derive an estimate of the Galactic abundance of cool planets in the mass regime from Jupiters to Sub-Neptunes.

The large-moon hypothesis states that planetary habitability is enhanced by the presence of a large satellite. This controversial proposal is linked to the equally controversial idea that the axial stability of a planet also enhances habitability. Previous work has shown that, far from encouraging axial stability, large moons actually destabilize obliquity when the effects of tidal drag on the planetary spin rate are taken into account. However, our Moon's mass is remarkably close to the upper limit allowed by axial stability, suggesting that the large-moon hypothesis is actually correct but constrained by an independent requirement for axial stability. This conclusion can be tested by looking at the typical separations between large exo-planets because axial stability is more likely in planetary systems with widely spaced gas giants. Thus, if axial stability really does enhance habitability, Jupiter and Saturn should be unusually widely spaced. This can be tested using data expected from gravitational microlensing planet-search surveys. Unfortunately, in the event of a negative result from this test, it is not possible to distinguish whether this results from large moons and stable axes being unimportant for life or results from large moons and stable axes being widespread.