Abstract: We present new, high angular resolution images of HD 199143 in the Capricornus association, obtained with the adaptive optics system ADONIS+SHARPII at the ESO 3.6 m Telescope of La Silla Observatory. HD 199143 and its neighbour star HD 358623 (separation ~$5'$ away) have previously been imaged with adaptive optics. For each star, a companion has been detected in the J and K bands at respective separations of $1.1''$ and $2.2''$ (Jayawardhana & Brandeker [CITE]). Our new photometry of HD 199143 B suggests that it is a M2 star and that the presence of circumstellar dust proposed by van den Ancker et al. ([CITE]) is no longer necessary. We show that the 12 μm flux detected by IRAS previously interpreted as an IR excess, can be explained by the presence of the late-type companion.

Abstract: The Submillimetron is the international project of the space telescope for full sky survey in submillimeter region 0.15-1.5 mm using facilities of the Russian segment of the International Space Station (ISS). A free flying module for the project is under development in corporation Energia. Periodic docking of the module to the ISS gives possibility to combine low cost with reliability, refilling, repairment and maintenance. The concept of the telescope combines a 0.6 m mirror cooled to liquid helium temperature with a novel type of microbolometers arrays developed at Chalmers University (Sweden). This combination gives unique possibility to realize background limited sensitivity about 10-18 W/Hz-1/2 in the spectral minimum of the extraterrestrial background near frequency 1 THz between peaks of galactic dust emission and CMB. The angular resolution of the instrument is about 1 arcmin, field of view ~1°.

Abstract: Accretion disks are pivotal elements in the formation and early evolution of solar-like stars. On top of supplying the raw material, their internal conditions also regulate the formation of planets. Their study therefore holds the key to solve this long standing mystery: how did our Solar System form? This chapter focuses on observational studies of the circumstellar environment, and in particular of circumstellar disks, associated with pre-main sequence solar-like stars. The direct measurement of disk parameters poses an obvious challenge: at the distance of the typical star forming regions ( e.g. ~140 pc for Taurus), a planetary system like ours (with diameter ≅50 AU out to Pluto, but excluding the Kuiper belt which could extend much farther out) subtends only 0.35''. Yet its surface brightness is low in comparison to the bright central star and high angular and high contrast imaging techniques are required if one hopes to resolve and measure these protoplanetary disks. Fortunately, capable instruments providing 0.1'' resolution or better and high contrast have been available for just about 10 years now. They are covering a large part of the electromagnetic spectrum, from the UV/Optical with HST and the near-infrared from ground-based adaptive optics systems, to the millimetric range with long-baseline radio interferometers. It is therefore not surprising that our knowledge of the structure of the disks surrounding low-mass stars has made a gigantic leap forward in the last decade. In the following pages we will attempt to describe, in a historical perpective, the road that led to the idea that most solar-like stars are surrounded by an accretion disk at one point in their early life and how, nowadays, their structural and physical parameters can be estimated from direct observations. We will follow by a short discussion of a few of the constraints available regarding the evolution and dissipation of these disks. This last topic is particularly relevant today to understand the mechanism leading to the formation of planets.