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During recent years considerable efforts have been aimed at the development and use of photometric systems, applicable to very large samples of stars and under the constraints of space-based observations. These systems should be capable of recognizing stars of most spectral types and peculiarities in case of high and non-uniform values of interstellar absorption. In general, these are multi-color intermediate-band systems assuring stellar photometry of very high precision, robustness of the system transformability against different implementations and capability of determining stellar parameters precisely.

The HH 110 jet presents a complex morphology in the optical images, with noticeable wiggles along the length of the jet. New proper motions have been calculated from [SII] CCD images obtained with a time baseline of ~ 15 yr. As a general trend, the HH 110 proper motions show a westward tilt with respect to the jet axis direction. Our results show evidence of an anomalously strong interaction between the outow and the surrounding environment. These results reinforce the scenario proposed by several authors, in which HH 110 emerges as the result of a grazing collision of the HH 270 jet (another jet, at 3′ to the NE of HH 110) with a dense clump of molecular gas.

Cosmic ray (CR) nuclei are accelerated particles which move randomly through the interstellar medium (ISM), where they suffer scattering, reacceleration and energy loss processes before reaching Earth. Spallation processes also take place forming secondary nuclei by fragmentation of heavier ones. Due to the impossibility of observing directly their original direction, the determination of possible sources where these particles originated requires the use of codes to simulate the propagation of CR within the Galaxy. This consists of a spiral disk with a thickness of 2h ~ 200 pc, where CR are created, and a halo with a height H, where they diffuse.

ISOGAL is a 7 and 15 μm survey of the inner Galactic disk, combined with DENIS near-infrared data [4]. The observed area covers ~16 deg of the Galactic disk and bulge, with a sensitivity ~10 mJy, nearly 100 times better than . A catalogue of ~10 infrared point sources was extracted from these data [6]. Most of them are evolved stars on the asymptotic giant branch (), but a few percent are interpreted as young stellar objects (). In particular, this survey covers the inner Galactic bulge (|| ≤ 1.5°, || ≤ 0.5°) almost completely.

Cosmic masers became a powerful tool for study of stellar evolution in the Galaxy, bursts of star-formation in external galaxies, and accretion disks around central black holes in active galaxies. Due to the small size and narrow line width of maser spots it is possible to measure transversal and radial velocity with high accuracy. Kinematics of the maser spots often reveals expansion and outflow of the matter from proto-stars and new-born stars, or rotation of circumstellar and circumnuclear disks. Stellar may disks contain proto-planets, and maser spots can trace their orbits. Parameters of the circumnuclear disks measured with maser spot motion are directly related to the mass of the central black hole. Another result of the study of maser kinematics is determination of distance to proto-stars and to galaxies. In the latter case the distance determination is independent of the red shift distance and may be used for the determination of the geometry of the Universe. The accuracy of the kinematic measurements of masers is limited by the available angular resolution, time span and sensitivity of VLBI systems used for such observations. The available time span is limited by the fast time variations of masers, especially variations in HO masers. Many of the masers studied with VLBI have unresolved maser spots, even at the highest resolution. Examples of OH masers unresolved on the space-ground baselines of the Japanese interferometer HALCA are given in [1,2]. In HO maser W3(OH) the fringe amplitude remains constant from zero baseline up to 635 , which corresponds to the angular size of less than 0.06 milliarcsec [3]. High angular resolution images of methanol maser spots reveal presence of the position-velocity gradient across the spots from 3.3 to 50 AU/km s . Bandwidth smearing of maser spot images may cause apparent increase of the size when measured with low spectral resolution. In NGC7538 0.1 km s spectral resolution will cause increase of the angular size to 1.9 mas [4]. In W3(OH) the same spectral resolution will smear 12 GHz methanol maser spot images to the size from 0.15 to 2 mas [5]. Similar gradient may be present in OH and HO masers. It is interesting that the position-velocity gradient of the same magnitude is required by OH maser pump models in order to provide non-local overlap of far-infrared rotational lines [6]. observations with high spectral resolution like those described in [5] show that when the spectral resolution is sufficient to avoid bandwidth smearing the maser spots remain unresolved. Therefore more angular resolution is needed in order to image maser spots. For the masers the only way to increase angular resolution is to increase the baseline, up to the space baselines. The imaging of the maser spots is one of the goals of the space-ground interferometer .

Various techniques are being used to search for extra-solar planetary signatures, including accurate measurement of positional (astrometric) displacements, gravitational microlensing, and photometric transits. Planned space experiments promise a huge increase in the detections and statistical knowledge arising from transit and astrometric measurements. Direct detection of even nearby Earth-mass planets in the habitable zone and the measurement of their spectral characteristics, typified by the TPF and Darwin missions, represents a considerable challenge. Beyond TPF/Darwin, Life Finder would aim to produce confirmatory evidence of the presence of life, while an Earth ‘imager’, some massive interferometric array providing resolved images of a distant Earth, appears only as a distant vision. A 10 nano-arcsec astrometric mission would detect ‘Earths’ systematically out to 100 pc.

Realistic models of Extremely Large Telescopes (ELTs), including adaptive optics system and segmented mirrors, ranging from 10 to 100m diameter have been used to simulate observations of extra-solar systems. It appears from these simulations that a 100m diameter OWL will permit detailed observations of a large number of Extra Solar Planets (ESPs), including Earth-like, a 60m would be much more limited, and a 30m could observe ESPs only if we are lucky enough to find such objects in the very near neighborhood.

High-precision astrometry, applied to extrasolar planet detection, promises to be the most suitable technique to complement the increasing population of exoplanets detected by radial velocity surveys. At radio-wavelengths, present ground-based arrays already provide astrometric precisions at μas levels, comparable to those planned by future space-based instruments. The necessary boost in sensitivity will come from future instruments, such as the Square Kilometer Array, which will provide both the sensitivity and resolution needed for a survey of stars to contribute significantly to the planetary search.

We are currently investigating the possibilities for a high-contrast, adaptive optics assisted instrument to be placed as a 2nd-generation instrument on ESO’s VLT. This instrument will consist of an “extreme-ao” system capable of producing very high Strehl ratios, a contrast-enhancing device and an integral-field spectroscopic detection system. It will be designed directly take images of sub-stellar companions of nearby (< 100 pc) stars. We will present our current design study for such an instrument and discuss the various ways to tell stellar from companion photons. Results of our latest simulations regarding the instrument will be presented and the expected performance discussed. Derived from the simulated performance we will also give details about the expected science impact of the planet finder. This will comprise the chances of finding different types of exo-planets, the scientific return of such detections and follow-up examinations, as well as other topics like star-formation, debris disks, and planetary nebulae.

Deriving orbital parameters and masses of extrasolar planets by means of measuring the variation of the host star positions requires an astrometric accuracy of 10 microarcsec. To achieve this goal, a consortium with partners from Germany, the Netherlands, and Switzerland, in agreement with ESO, will enhance the PRIMA facility at the VLTI with Differential Delay Lines (DDLs). We give an overview of the PRIMADDL project, which consists of developing hardware, astrometric operation tools, and data reduction software, and outline the anticipated astrometric planet search program to be carried out with this facility.