In this contribution, we estimate the temperature at the surface of known exoplanets and of their putative satellites for two albedo extreme cases (Venus and Mars) and present a selection of extremophiles living on Earth that can live under those conditions. We examine also the possibility of survival of microorganisms in planetary systems of variable stars.

In the frame of Symposium 264 which concerns Solar and Stellar Variability we address the space solar missions devoted to the various aspects of solar activity. We describe them in three time categories: missions ready for launch, missions which will operate in the 2012-2015 time frame and ambitious missions to be launched after 2015. We focus on the contributions of these missions according to the following criteria: Understanding mechanisms of activity, Improving detection and characterisation, Working out some prediction. Major activity contributors and manifestations are addressed: Coronal Mass Ejections, Flares, Solar winds, Magnetism (including dynamo), Irradiance.

The Kepler mission will obtain high precision, continuous lightcurves for more than ~150,000 stars over the next four years. Prior to primary mission operations, ten days of commissioning data were obtained for the ~52,000 brightest targets in the Kepler field. While Kepler's main goal is the discovery of transiting low mass planets, it will also provide a rich dataset for studies of variable stars. These commissioning data give a first glimpse of the amazing diversity of stellar variability Kepler will observe. Here, we discuss the tools we are currently developing to quantify variability in the Kepler data, and show initial results on the distribution of target stars in these metrics. Ultimately these measures will be used both to characterize the data and to select active rotationally modulated stars for rotation period determination.

The lunar regolith (soil) has recorded a history of the early Moon, the Earth, and the entire solar system. A major goal of the developing lunar exploration program should be to find and play back existing fragments of that tape. By playing back the lunar tape, we can uncover a record of planetary bombardment, as well as solar and stellar variability. The Moon can tell us much about our place in the solar system and in the Universe. The lunar regolith has likely recorded the original meteoritic bombardment of Earth and Moon, a violent cataclysm that may have peaked around 4 GY, and the less intense bombardment occurring since that time. Decrease in bombardment allowed life to develop on Earth. This impact history is preserved as megaregolith layers, ejecta layers, impact melt rocks, and ancient impact breccias. The impact history for the Earth and Moon possibly had profound effects on the origin and development of life. Life may have arrived via meteorite transport from a more quiet body, such as Mars. The solar system may have experienced bursts of severe radiation from the Sun, other stars or from unknown sources. The lunar regolith has also recorded a radiation history in the form of implanted and trapped solar wind and solar flare materials and radiation damage. The Moon can be considered as a giant tape recorder containing the history of the solar system. Lunar soil generated by small impacts will be found sandwiched between layers of basalt or pyroclastic deposits. This filling constitutes a buried time capsule that is likely to contain well-preserved ancient regolith. Study of such samples will show us how the solar system has evolved and changed over time. The lunar recording can provide detailed snapshots of specific portions of solar and stellar variability.

Extreme Ultraviolet (EUV) and X-ray emission is of great importance in several phenomena related to the formation of planetary systems and the atmospheres of planets. The atmospheric composition, and the mass of an exoplanet, are partly dependent on the X-ray and EUV radiation received during the first stages of formation and even during main sequence of the star. Biological life developing on exoplanets would depend severely on the high energy radiation arriving from its parent star.

Here we present a database of the X-ray and EUV emission of all the stars currently known to host exoplanets. The archive is public and accessible through the Spanish Virtual Observatory (SVO). The database gives the user the option to download observed X-rays and EUV spectra. Synthetic spectra covering the spectral range 1–912 Å are also available (present day telescopes do not give access to the EUV range at λ > 180 Å). These spectra are created using coronal models after fitting observed spectra.

Brazilian Solar Spectroscope (BSS) carry out high time (0.01–0.1 s) resolution solar spectral investigations within the frequency range 1–2.5 GHz on a daily basis. At the moment, a new site is imposed to this facility. This site change became necessary due to both factors: the growing level of radio frequency interference (RFI) signals at actual site and requirements of rising up a new building at the BSS antenna location. We present results of RFI signals search at INPE-Cachoeira Paulista area as purpose to define a new BSS site.

The Observatório Nacional at Rio de Janeiro has developed a new heliometer to perform accurate measurements of the solar diameter. The equipment makes use of split parabolic mirrors, rather than split achromatic lenses as objective. In its first campaign this reflector heliometer generated a few thousands of images of the Sun through which we evaluate the precision of the solar diameter measurements as been 5 mas. The mechanical and thermal stability of the instrument is guaranteed by the use of a telescope tube manufactured in carbon fiber. The tube firmly holds the heliometric mirrors and the CCD camera that collects the images. The perfect lodging between the two half-mirrors over its supporting plate defines the angular instrumental separation between the two images of the sun. The heliometric mirrors and supporting plate have been made in ceramic material in order to ensure the stability of the optical configuration and to maintain the two images of the solar disk displaced by a fixed angle in relation to each other. To verify the stability of the instrument we designed the procedures of collimation and comparison. The collimation consists of using the heliometer for measuring the diameter of an artificial solar image specifically created for this purpose. The comparison is performed by measuring the residual unfold of a punctual image after been unfold by two opposed heliometers. The heliometric approach allows the measurement of the solar diameter at any heliolatitude and can be undertaken as often as desired. Computer programs have been developed for automated image acquisition and analysis. The optical and mechanical design has been performed by using 3D computer aided design software.

The configuration of the second phase of the Brazilian Decimetric Array (BDA), installed at Cachoeira Paulista, Brazil (Longitude 45° 0′ 20″ W and Latitude 22° 41′ 19″ S), is a T-shaped array where 21 antennas are being added to existing 5 antennas of the first phase. In the third phase, in each arm of the T array, four more antennas will be added and baselines will be increased to 2.5 × 1.25 km in east-west and south directions, respectively. The antennas will be equally spaced at the distances of 250 meters from the central antenna of the T-array. Also, the frequency range will be increased to 1.2–1.7, 2.8 and 5.6 GHz. The Second phase of the BDA should be operational by the middle of 2010 and will operate in the frequency range of (1.2–1.7) GHz for solar and non solar observations. Here, we present the characteristics of the second phase of the BDA project, details of the array configuration, the u-v coverage, the synthesized beam obtained for the proposed configuration.

To study effects of stellar variability, it is necessary to have complete lists of variable stars with good coordinates, correct variability ranges, reliable classification. The General Catalogue of Variable Stars (GCVS) is one of the main sources of information of this kind. Recently, the flow of information on stellar variability has increased strongly, requiring new approaches to GCVS compilation. New classification schemes are needed for variable stars, taking into account the development of our knowledge. We present information on the current state of the GCVS, its web data base, new Name-Lists containing thousands of new variables. We also discuss the problems of developing a new classification system for variable stars, of implementing catalogs of variable stars based on automatic surveys into the GCVS, of cooperation and interaction between the GCVS and other important sources of information on variable stars.

The Indian National Large Solar Telescope (NLST) will be a state-of-the-art 2-m class telescope for carrying out high resolution studies of the solar atmosphere. Sites in the Himalayan region at altitudes greater than 4000-m that have extremely low water vapor content and are unaffected by monsoons are under evaluation. This project is led by the Indian Institute of Astrophysics and has national and international partners.

NLST is an on-axis alt-azimuth Gregorian multi-purpose open telescope with the provision of carrying out night time stellar observations using a spectrograph. The telescope utilizes an innovative design with low number of reflections to achieve a high throughput and low instrumental polarization. High order adaptive optics is integrated into the design that works with a modest Fried's parameter of 7-cm to give diffraction limited performance. The telescope will be equipped with a suite of post-focus instruments including a high resolution spectrograph and a polarimeter. A detailed concept design of the telescope is presently being finalized and fabrication is expected to begin in 2010 with first light in 2014.

The symposium has shown the dynamism of this rapidly evolving discipline. I shall concentrate here on some highlights and some complementary informations. I conclude on open questions with some perspectives on solar & stellar activity and related planets.