A test for the search for life on extrasolar planets
نویسندگان
چکیده
We report spectroscopic observations (400−800 nm, R ≈ 100) of Earthshine in June, July and October 2001 from which normalised Earth albedo spectra have been derived. The resulting spectra clearly show the blue colour of the Earth due to Rayleigh diffusion in its atmosphere. They also show the signatures of oxygen, ozone and water vapour. We tried to extract from these spectra the signature of Earth vegetation. A variable signal (4 to 10± 3%) around 700 nm has been measured in the Earth albedo. It is interpreted as being due to the vegetation red edge, expected to be between 2 to 10% of the Earth albedo at 700 nm, depending on models. We discuss the primary goal of the present observations: their application to the detection of vegetation-like biosignatures on extrasolar planets.
منابع مشابه
[Extrasolar terrestrial planets and possibility of extraterrestrial life].
Recent development of research on extrasolar planets are reviewed. About 120 extrasolar Jupiter-mass planets have been discovered through the observation of Doppler shift in the light of their host stars that is caused by acceleration due to planet orbital motions. Although the extrasolar planets so far observed may be limited to gas giant planets and their orbits differ from those of giant pla...
متن کاملDarwin--a mission to detect and search for life on extrasolar planets.
The discovery of extrasolar planets is one of the greatest achievements of modern astronomy. The detection of planets that vary widely in mass demonstrates that extrasolar planets of low mass exist. In this paper, we describe a mission, called Darwin, whose primary goal is the search for, and characterization of, terrestrial extrasolar planets and the search for life. Accomplishing the mission ...
متن کاملA search for water masers toward extrasolar planets
Context. Water is the most common triatomic molecule in the universe and the basis of life on Earth. Astrophysical masers have been widely studied in recent years and have been shown to be invaluable probes of the details of the environment in which they are found. Water masers, for instance, are often detected toward low-mass star-forming regions. Doppler radial-velocity surveys have detected ...
متن کاملThe search for Earth-like planets
Improved technology is leading to interesting new findings regarding extrasolar planets. NASA’s current list of exoplanets includes 403 objects. Research efforts including the Spitzer Space Telescope, the Wide Area Search for Planets (WASP), and Kepler have recently helped discover extrasolar planets that challenge naturalistic origins theories. Great efforts are underway to find exoplanets tha...
متن کاملImpact of Orbital Eccentricity on the Detection of Transiting Extrasolar Planets
For extrasolar planets with orbital periods, P>10 days, radial velocity surveys find non-circular orbital eccentricities are common, 〈e〉 ∼ 0.3. Future surveys for extrasolar planets using the transit technique will also have sensitivity to detect these longer period planets. Orbital eccentricity affects the detection of extrasolar planets using the transit technique in two opposing ways: an enh...
متن کاملUsing Transit Timing Observations to Search for Trojans of Transiting Extrasolar Planets
Theoretical studies predict that Trojans are likely a frequent byproduct of planet formation and evolution. We examine the sensitivity of transit timing observations for detecting Trojan companions to transiting extrasolar planets. We demonstrate that this method offers the potential to detect terrestrial-mass Trojans using existing ground-based observatories. We compare the transit timing vari...
متن کامل