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Fig. 3.5 The relationship between planetary mass and distance from the star (top) for the first 100 objects After Udry et al. (2003) the limit for detection at 10m.s_1 corresponds to the sensitivity limit for instruments in 2003 (bottom) for the objects currently listed limit), and by the fact that the sensitivity of our instruments has increased, we are forced to admit that the observations in 2002-2003 remain completely valid. An explanation of these observations may derive from the analysis...

Velocimetry

Velocimetry, which has enabled the detection of most of the known exoplanets, should continue to provide a series of results in future, all the more so, given that the technique has not yet been pushed to its limits. In addition, long-term monitoring of stars is essential to detect long-period planets. There are about ten current instruments or instrumental projects to detect planets by the radial-velocity method (cf. Chap. 2). Although each instrument is based on specific technical choices and...

How Should Life be Defined

Before undertaking a discussion on the search for extraterrestrial life, it is just as well to define what we mean by life. Perforce, the criteria are chosen based on the sole example at our disposal, that of life on Earth. Biologists agree on using the following criteria M. Ollivier et al., Planetary Systems. Astronomy and Astrophysics Library, DOI 978-3-540-75748-1.9, Springer-Verlag Berlin Heidelberg 2009 auto-reproduction (i.e., reproduction of identical organisms) evolution by mutations...

Plato

PLATO is a post-CoRoT and post-Kepler mission among the call for proposals for ESA's 2015-2025 (Cosmic Vision) programme. The main idea is that the formation and evolution of stars, their magnetic fields and their planets are intrinsically linked and should be studied simultaneously. PLATO therefore proposes to select a large sample of stars of all masses and ages (the sample including more than 100000 objects) to search for planets and define their characteristics by the transit method to...

Tfp0

TPF-O (Terrestrial Planet Finder - Occulter, Fig. 8.22) concept came from the realization than an internal coronagraph (as in the TPF-C design) requires both the wavefront correction and control to be of very high quality to avoid leakage of the stellar light. The consequence is a complex design with adaptive optics to correct wavefront residuals. By contrast, the use of an external occulter permits the elimination of the major part of the light before it enters the telescope. The main...

Migration in Exosystems

From the time of the first discoveries, the properties of exoplanets contradicted the scheme that had been developed of the formation of the Solar System. For example, several planets were discovered 0.05 AU from their star, where the temperature of the protoplanetary disk would not allow ices to condense, nor even refractory materials such as silicates. So the formation of a solid core was not possible. Yet a number of extrasolar planets were found at this distance from their stars (see Chap....

Z 20 10

Another interpretation that is possible from these data rests on the fact that systems of high metallicity preferentially form more massive planets, which are thus easier to detect with current methods. Finally, we should note that the Solar System is actually located in the metallicity zone where the probability of finding planets is low Another theory proposed to explain the excess metallicity is the presence of planets that have been engulfed and increased the metallic concentration of the...

The Environment of the Primitive Earth The Hydrosphere and Atmosphere

9.4.2.1 A Primordial Reducing Atmosphere The question of the composition of the primordial atmosphere remains far from being settled. Sources of hydrogen and of reduced compounds must have been significant on the early Earth. There would have been emission of volcanic H2 oxidation of iron by water, liberating H2 and the formation of CH4, NH3, and more complex organic molecules in the presence of H2 in hydrothermal systems. CH4 and NH3 are extremely fragile molecules once in the atmosphere,...

Naosconica

NAOS (Nasmyth Adaptive Optics System, Fig. 8.16) is the first set of adaptive optics mounted on one (Yepun) of the four 8.2-m telescopes of the European VLT on the summit of Mount Paranal in Chile. The instrument is coupled with the CONICA infrared camera (1-5 m). The system, which has a deformable mirror with 185 actuators, a special tip tilt wavefront correction system, and two wavefront analyzers (one in the visible region, and one in the near infrared), has been available to the scientific...

The Appearance of Life on the Primitive Earth 941 Favourable Conditions

Lying 1 AU from the Sun, Earth has benefited, ever since its formation, with a temperature that enabled liquid water to exist. Subsequently, it also acquired the conditions that allowed it to preserve this favourable environment. One essential process is plate tectonics, which ensures that atmospheric carbon dioxide is recycled. Plate tectonics, driven by the Earth's internal energy (whose origin is the radioactive decay of unstable isotopes within the interior), recycles oceanic crust by...

O5 B5 A5 F5 G5 K5 M5

A.2 An example of an HR diagram the main sequence is circled HOT Color index (B-V) COOL Fig. A.2 An example of an HR diagram the main sequence is circled This classification, solely based on the temperature of stars, divides them into 9 categories, of which the first 7 (O, B, A, F, G, K, and M) cover about 99 per cent of the stars in the sky. Table A.1 describes the different categories in the Harvard classification. This classification is now extended to the...

The Synthesis of Organic Molecules Miller and Ureys Experiment

How do we get from organic interstellar molecules to the amino acids necessary for the development of life One element of the answer was provided by the decisive experiment carried out in 1953 by Stanley Miller and Harold Urey. Several decades earlier, Oparin had suggested that micro-organisms could appear, in a reducing medium, at the end of a long series of chemical reactions involving complex organic molecules. Miller and Urey undertook to simulate the atmosphere of the primordial Earth by...

A2 Gravitation and Keplers Laws

Kepler's three laws, although predating Newton's theory, result from the law of universal gravitation, which postulates that 2 masses m1 and m2, separated by a distance R, exert on one another an attractive force F, parallel to the radius vector R that joins their respective centres of mass (this force being described as 'central'). This force is expressed by the relationship where G is the universal constant of gravitation ( 6.67 x 10 n N.m2.kg 2). Kepler's laws are always valid for a system...