Garik Israelian

Extensive spectroscopic studies of stars with and without planetary systems have concluded that planet host stars are more metal-rich than those without detectable planets. More subtle trends of different chemical elements begin to appear as the number of detected extrasolar planetary systems continues to grow. I review our current knowledge concerning the observed abundance trends of light and heavy elements in planet host stars and their possible implications. These studies may help us to...

Other biosignatures

Oxygenic photosynthesis is only one among many possible metabolisms invented by life on Earth, and during half of its history our planet had an anoxic atmosphere. Other sources of carbon are used (CO, CH4, organic molecules), as well as many sources of hydrogen or electron donors (H2S, S, H2, CH4, organic molecules, NH3, NO2, Fe2+, MN2+, SO42 , to name only a few). The outputs of these various metabolisms are present in our atmosphere as trace materials, with abundances of about, or lower than,...

Martian atmosphere Mumma Formisano Krasnopolsky

These measurements are all on the verge of spectroscopic believability, so one should retain some scepticism about this result. If it is correct, though, it may imply that there are methanogens (or their martian equivalents) living at depth within some subsurface aquifer. This is not inconceivable. Putting a high-resolution spectrometer into orbit around Mars to further test this possibility is an excellent idea. In any case, even though we cannot claim to understand the climate of...

Info

One of the first questions that immediately occurs is whether the discoveries are biased, as is very usual in astronomy because faint things are harder to see. Possible sources of bias introduced by the dominating radial velocity technique are (i) sensitivity of the radial velocity measurements (highest for large masses and short periods) (ii) the planet hunting grounds and hunting tactics (iii) the discovery race and issues of secrecy and selective publishing - in particular the focus on...

DM P Fs

Where 3 is the ratio of the radius at which most XUV radiation is absorbed to the planetary radius, p is the planet density and s is the XUV and Ly a flux at the planet's position. Vidal-Madjar . (2003) have detected a Ly a absorption in the atmosphere of the planet HD 209458b, with a large line width implying a high velocity of the hydrogen atoms escaping the planet. Vidal-Madjar . (2004) have also detected O and C in evaporation. These species must be carried out to the Roche lobe and beyond,...

Extrasolar Planets

XVI Canary Islands Winter School of Astrophysics HANS DEEG, JUAN ANTONIO BELMONTE, and ANTONIO APARICIO Instituto de Astrof sica de Canarias, Tenerife Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, Sao Paulo Cambridge University Press The Edinburgh Building, Cambridge CB2 8RU, UK Published in the United States of America by Cambridge University Press, New York www.cambridge.org Information on this title www.cambridge.org 9780521868082 Cambridge University Press 2008 This...

Laurance R Doyle

In this chapter we will describe in a general manner each planet detection method and examine the fundamental astrophysical parameters each technique measures as well as its present measurement limitations for the detection of inner giant planets, jovian outer planets, and Earthlike planets. We then outline several secondary detection methods that may be instituted in the near future with increased detection sensitivity. We then discuss the ranges of each detection method and sketch several...

Timothy M Brown

Transiting extrasolar planets provide the best current opportunities for characterizing the physical properties of extrasolar planets. In this chapter, I first describe the geometry of planetary transits, and methods for detecting and refining the observations of such transits. I derive the methods by which transit light curves and radial velocity data can be analyzed to yield estimates of the planetary radius, mass and orbital parameters. I also show how visible-light and infrared spectroscopy...

Uraniferous Conglomerate Ga

Stratigraphie sequence from the Huronian Supergroup in southern Canada. The entire sequence was deposited between 2.45 Ga and 2.2 Ga. The three glacial diamictite layers are underlain by sediments containing detrital uraninite and pyrite indicating low atmospheric O2 and are overlain by red beds indicating high O2 . After Young 1991. studied by Roscoe 1969, 1973 . These rocks, which were laid down between 2.45 and 2.2 Ga, contain three glacial layers diamictites . Below the...

Temperature and radius of the planets

Simultaneously with the information on the chemical composition of a planet's atmosphere, it would be very interesting to obtain information on the surface temperature from thermal emission as an indicator of its habitability. What can we know, remotely, about the temperature of an exoplanet This question is far from easy to answer. In theory, spectroscopy can provide some detailed information on the thermal profile of a planetary atmosphere. This, however, requires a spectral resolution and...

Oxygen and ozone as biosignatures

In order to investigate the astrobiological possibilities of the missions, it is necessary to estimate the risk of false positive and false negative detection. A false positive case results from the detection of an abiotic feature that is wrongly attributed to some form of biological activity. On the other hand, a false negative case occurs when an inhabited planet does not present any of the features sought, whether because the dominant metabolisms do not produce the required biosignature or...