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http://www.france24.com/france24Public/en/news/world/20070422-Astronomy-red-dwarf-mother-earth.html
this item first appeared in the Malaysia Sun AFAIK
this item first appeared in the Malaysia Sun AFAIK
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PARIS, April 24, 2007 (AFP) - Astronomers reported on Wednesday they had discovered a "super-Earth" more than 20 light years away that is the most intriguing world found so far in the search for extraterrestrial life.
neutrino said:Alright, it seems to official now. :)
http://www.space.com/scienceastronomy/070424_hab_exoplanet.html
http://news.yahoo.com/s/ap/20070424/ap_on_sc/habitable_planetBesides having the right temperature, the new planet is probably full of liquid water, hypothesizes Stephane Udry, the discovery team's lead author and another Geneva astronomer
Well, it's PopSci - science for appeal to the general public, so the statements are designed to capture the imagination.OSalcido said:where the heck did he pull this from? how can he say it is "probably full of water"? I mean, Venus and Mars are in the solar system's goldilocks zone... and there's no appreciable amount of water on either one of them. that's a 66% chance of not having water, right? am i missing something?
Good points, and it is about 0.073 AU or 11 million km from the red dward, yet the astronomers are apparently projecting average surface temperature of 0–40 °C (32–104 °F). The atmosphere would certainly be denser than earth's.It's orbiting a tiny Red Dwarf and it's much closer to it's star. I know some reddwarfs are prone to violent solar flares that would blast this planet into a barren moonscape if it ever got hit by one.
dimensionless said:I would say that it is worthy of reporting. I would also point out that water is very plentiful in this solar system.
In terms of relative abundance in the 'cosmic mix', the most abundant element is hydrogen (~75%), then helium {~23%) and the next most abundant element is oxygen (~1%), after which comes carbon (~0.5%). Everything else, including the silicon and iron of our own Earth planet, is to be found in the remaining ~ 0.5%! (% by mass).matt.o said:Actually, water is one of the most abundant molecules in the Universe. It is found in star formation regions and cold molecular clouds. The 22GHz water maser line is the strongest spectral line observed in the radio Universe.
I agree that the signature of free oxygen is life's 'smoking gun' to look out for.Wallace said:Slightly tangential question here, but is anyone aware of the state of spectral observations of extra solar planets? I know it's never been done but I think there are efforts to try and do it, but I'm not much of an observer so I'm not sure of the state of the art.
It seems logical to me that the presence of [tex]O_2[/tex] in the atmosphere is a far clearer indicator of life than the existence of liquid water on the surface, but much harder to infer of course!
The field of extrasolar planets has rapidly expanded to include the detection of planets with masses smaller than that of Uranus. Many of these are expected to have little or no hydrogen and helium gas and we might find Earth analogs among them. In this paper we describe our detailed interior models for a rich variety of such massive terrestrial and ocean planets in the 1-to-10 earth-mass range (super-Earths). The grid presented here allows the characterization of the bulk composition of super-Earths detected in transit and with a measured mass. We show that, on average, planet radius measurements to better than 5%, combined with mass measurements to better than 10% would permit us to distinguish between an icy or rocky composition. This is due to the fact that there is a maximum radius a rocky terrestrial planet may achieve for a given mass. Any value of the radius above this maximum terrestrial radius implies that the planet contains a large (> 10%) amount of water (ocean planet).
Wallace said:Slightly tangential question here, but is anyone aware of the state of spectral observations of extra solar planets? I know it's never been done but I think there are efforts to try and do it, but I'm not much of an observer so I'm not sure of the state of the art.
It seems logical to me that the presence of [tex]O_2[/tex] in the atmosphere is a far clearer indicator of life than the existence of liquid water on the surface, but much harder to infer of course!
THE INFRARED SPECTRUM OF EXOPLANETS
M. Ollivier
Institut d’Astrophysique Spatiale - Université de Paris-Sud (marc.ollivier@ias.u-psud.fr)
At a time where a program of space mission dedicated to the direct detection and spectral analysis of extrasolar planets is under development both at ESA and NASA
(Darwin/TPF), the choice of the observation spectral window is still not completely clear between near and thermal infrared. In this paper, I review the question of infrared spectrum of both giant and telluric exoplanets, in these two spectral windows. Particularly, I focus on the information the continuum and the spectral features can provide, in term of size and temperature of the planet, composition and depth of its atmosphere. I show that spectra in the thermal infrared (between 6 and 20 microns) at
a typical spectral resolution of 20 to 50 are sufficient to determine roughly the nature of the atmosphere (reducing or oxidizing) and its major components. As a conclusion, I show that thermal infrared is also suited to identify molecular species that can be used as bio-tracers in the atmosphere of telluric extrasolar planets.
EXOPLANETS:
a picture at last?
For the first time, an international team has apparently managed to photograph a planet in orbit around a star other than our Sun. But until their initial results are confirmed by other observations, the researchers are remaining very cautious...
Planet in view?
Then in April 2004, the researchers observed a very cold and very faint body near to brown dwarf 2M1207, only just perceptible through the telescope’s infrared camera. Spectral analysis, carried out with great difficulty because of the object’s low luminosity, showed that it held water! The body was provisionally named GPCC, “Giant Planet Candidate Companion”…
The discovery of the most earthlike exoplanet is significant because it brings us one step closer to finding a habitable planet outside of our solar system. This planet, known as LHS 1140b, has many similarities to Earth, including its size and distance from its star, making it a prime candidate for potential life.
The ESO team used the High Accuracy Radial velocity Planet Searcher (HARPS) instrument to measure the mass of the planet and its distance from its star. They also observed the planet passing in front of its star, which allowed them to calculate its size. These measurements, along with other data, led to the conclusion that LHS 1140b is the most earthlike exoplanet yet.
While LHS 1140b has many earthlike characteristics, it is still unknown if it can support life. The planet orbits a red dwarf star, which is known to have high levels of radiation and can be unstable. Additionally, the planet's atmosphere and other factors are still being studied to determine its habitability.
LHS 1140b is located about 40 light years away from Earth. This may seem like a vast distance, but in the grand scheme of the universe, it is relatively close. With advancements in technology, it may be possible to send spacecraft to this exoplanet in the future.
The discovery of LHS 1140b is a major step forward in the search for extraterrestrial life. It shows that there are other planets in the universe that have similar characteristics to Earth, increasing the likelihood that there may be other forms of life out there. It also provides scientists with a target for further study and potential future exploration.