A novel SETI strategy targeting the solar focal regions of the most nearby stars

Many hypotheses have been raised to explain the famous Fermi paradox. One of them is that self-replicating probes could have explored the whole Galaxy, including our Solar System, and that they are still to be detected. In this scenario, it is proposed here that probes from neighboring stellar systems could use the stars they orbit as gravitational lenses to communicate efficiently with each other. Under this hypothesis, a novel SETI approach would be to monitor the solar focal regions of the most nearby stars to search for communication devices. The envisioned devices are probably not detectable by imagery or stellar occultation, but an intensive multi-spectral monitoring campaign could possibly detect some communication leakages. Another and more direct option would be to message the focal regions of nearby stars in an attempt to initiate a reaction.     

Observational signatures of nanoflare heated solar stellar coronae

Using time-dependent dynamical models of the radiating gas in coronal flux tubes, we identify features in UV spectral line profiles that can reveal the direction in which energy flows through the solar transition region, in observations without temporal or spatial resolution. The profile features survive spatial and temporal averaging through non-linear dependencies of the line emission coefficients on thermal properties of the plasma that are correlated with the material velocity. This approach requires only low noise data of high spectral resolution and could naturally be applied to stars as well as the solar corona. We make predictions for the SUMER instrument that can in principle test whether energy propagates upwards or downwards in coronal flux tubes, suggesting a new angle of attack on the long standing problem of determining coronal heating mechanisms.     

Comparative study of the influence of natural convection on directional solidification of Al–3.5 wt% Ni and Al–7 wt% Si alloys

We present numerical simulations of thermosolutal convection for directional solidification of Al–3.5 wt% Ni and Al–7 wt% Si. Numerical results predict that fragmentation of dendrite arms resulting from dissolution could be favored in Al–7 wt% Si, but not in Al–3.5 wt% Ni. Corresponding experiments are in qualitative agreement with the numerical predictions. Distinguishing the two fragmentation mechanisms, namely dissolution and remelting, is critical during experiments on earth, when fluid flow is dominant.     

First laser measurements to space debris in Poland

The Borowiec Satellite Laser Ranging station (BORL 7811, Borowiec) being a part of the Space Research Centre of the Polish Academy of Sciences (SRC PAS) went through modernization in 2014–2015. One of the main tasks of the modernization was the installation of a high-energy laser module dedicated to space debris tracking. Surelite III by Continuum is a Nd:YAG pulse laser with 10?Hz repetition rate, a pulse width of 3–5?ns and a pulse energy of 450?mJ for green (532?nm). This new laser unit was integrated with the SLR system at Borowiec performing standard satellite tracking. In 2016 BORL 7811 participated actively to the observational campaigns related to the space debris targets from LEO region managed by the Space Debris Study Group (SDSG) of the International Laser Ranging Service (ILRS).Currently, Borowiec station regularly tracks 36 space debris from the LEO regime, including typical rocket bodies (Russian/Chinese) and cooperative targets like the inactive TOPEX/Poseidon, ENVISAT, OICETS and others. In this paper the first results of space debris laser measurements obtained by the Borowiec station in period August 2016 – January 2017 are presented. The results gained by the SRC PAS Borowiec station confirm the rotation of the defunct TOPEX/Poseidon satellite which spins with a period of approximately 10?s. The novelty of this work is the presentation of the sample results of the Chinese CZ-2C R/B target (NORAD catalogue number 31114) which is equipped (probably) with retroreflectors. Laser measurements to space debris is a very desirable topic for the next years, especially in the context of the Space Surveillance and Tracking (SST) activity. Some targets are very easy to track like defunct ENVISAT or TOPEX/Poseidon. On the other hand, there is a big population of different LEO targets with different orbital and physical parameters, which are challenging for laser ranging like small irregular debris and rocket boosters.     

Study of the NGC 2770 interstellar medium through Hα, millimetric and optical polarimetric data of SN 2008D and SN 2007uy

We present the preliminary results of the recent H_α narrow-band imaging carried out for NGC 2770 with the Gran Telescopio Canarias (GTC) equipped with OSIRIS. We put the polarization measurements reported in Gorosabel et al. (2010) for SN 2007uy and SN 2008D in the context of the morphological information inferred from the H_α imaging. We estimated the orientation of the interstellar polarization (ISP) at the position of SN 2007uy and, most interestingly, at the site of SN 2008D which has been subject of an intensive debate due to its possible connection with Gamma-Ray Bursts (GRBs). The H_α imaging reveals a clumpy interstellar medium (ISM) composed of hundreds of compact emitting regions, for which we determined their sizes. The derived size for the H_α emitting region coincident with SN 2008D is consistent with the ISM cell size limits imposed by Gorosabel et al. (2010) based on millimetric data. A deeper data analysis is under way and will be published elsewhere. This article represents the first attempt to study the site of a possible GRB-like event combining millimetric, polarimetric and narrow-band data.     

Determination of surface global radiation from meteosat images using relative brightness as new parameter to characterize the cloudiness

For the investigation of radiative properties of clouds using satellite images an objective parameter is required which is independent of conditions of illumination and of recorders. We found a new parameter - the relative brightness - which seems to serve this purpose. Using the relative brightness the daily amount of surface global radiation can be determined easily by linear regression with sufficient accuracy from METEOSAT images. Period between November 1981 and July 1983 was studied and our results are not worse than the ones using more complicated methods.     

Observing Chaos in External Spiral Galaxies

The feasibility of observing chaotic behavior in the stellar component of spiral galaxies is discussed. Three sources for development of chaos are considered namely: steep potential gradients, resonances and growing spiral perturbations. Several regions where chaos could be expected are identified such as the very central region, the end of the bar, the start of the main spiral pattern and the termination of strong spiral arms.The main observational signature is likely to be an increased velocity dispersion while multiple peaks in the velocity profile due to bifurcation of the main family of periodic orbits near resonances could be viewed as an indicator of increased stochasticity. It is non-trivial to distinguish between a higher velocity dispersion due to chaotic motions and non-periodic orbits trapped around the central family of stable periodic orbits. This requires a good dynamic model which can be obtained by combining near-infrared K surface photometry maps and kinematic information.The ESO VLT 8m unit telescopes were taken as a reference to judge if it is feasible to observe chaos in disk galaxies with current state-of-the-art equipment. Whereas surface photometry map easily can be obtained with smaller telescopes, detailed line-of-sight velocity profiles from absorption lines are difficult to observed below an isophotal level of I20 mag/ even with an 8m class telescope. This suggests that it would be possible to observe chaotic behavior in spiral galaxies out to the end of the bar or start of the main spiral pattern but not further out in the spiral arms.     

Atmospheric Science with InSight

In November 2018, for the first time a dedicated geophysical station, the InSight lander, will be deployed on the surface of Mars. Along with the two main geophysical packages, the Seismic Experiment for Interior Structure (SEIS) and the Heat-Flow and Physical Properties Package (HP³), the InSight lander holds a highly sensitive pressure sensor (PS) and the Temperature and Winds for InSight (TWINS) instrument, both of which (along with the InSight FluxGate (IFG) Magnetometer) form the Auxiliary Sensor Payload Suite (APSS). Associated with the RADiometer (RAD) instrument which will measure the surface brightness temperature, and the Instrument Deployment Camera (IDC) which will be used to quantify atmospheric opacity, this will make InSight capable to act as a meteorological station at the surface of Mars. While probing the internal structure of Mars is the primary scientific goal of the mission, atmospheric science remains a key science objective for InSight. InSight has the potential to provide a more continuous and higher-frequency record of pressure, air temperature and winds at the surface of Mars than previous in situ missions. In the paper, key results from multiscale meteorological modeling, from Global Climate Models to Large-Eddy Simulations, are described as a reference for future studies based on the InSight measurements during operations. We summarize the capabilities of InSight for atmospheric observations, from profiling during Entry, Descent and Landing to surface measurements (pressure, temperature, winds, angular momentum), and the plans for how InSight’s sensors will be used during operations, as well as possible synergies with orbital observations. In a dedicated section, we describe the seismic impact of atmospheric phenomena (from the point of view of both “noise” to be decorrelated from the seismic signal and “signal” to provide information on atmospheric processes). We discuss in this framework Planetary Boundary Layer turbulence, with a focus on convective vortices and dust devils, gravity waves (with idealized modeling), and large-scale circulations. Our paper also presents possible new, exploratory, studies with the InSight instrumentation: surface layer scaling and exploration of the Monin-Obukhov model, aeolian surface changes and saltation / lifing studies, and monitoring of secular pressure changes. The InSight mission will be instrumental in broadening the knowledge of the Martian atmosphere, with a unique set of measurements from the surface of Mars.     

Planned Products of the Mars Structure Service for the InSight Mission to Mars

Space Science Reviews - The InSight lander will deliver geophysical instruments to Mars in 2018, including seismometers installed directly on the surface (Seismic Experiment for Interior Structure,...