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"What is the most widely accepted theory on how photosynthesis evolved from non-photosynthesis based life?"
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Seminar Detail
Infrared Spectra of Extrasolar Planets
Presenter: Drake Deming ()
March 26, 2007 11:00 AM Pacific
Two independent scientific groups have recently reported the first spectroscopy of planets orbiting other stars, using the Spitzer Space Telescope. The planets (HD 209458b and HD 189733b) are "hot Jupiters" orbiting within 0.05 AU of solar-type stars, and with orbital periods from 2.2 to 3.5 days. Their orbital planes are close to our line of sight, so both planets pass in front of ("transit"), and disappear behind their stars, once each orbit. The Spitzer measurements were made by subtracting the spectrum of each star - with the planet in eclipse - from the combined infrared light of the system, to yield the infrared spectrum of the planet alone. Theorists expected that absorption by hot water vapor would dominate the spectra of these planets in the 7- 14-micron wavelength region. However, neither planet shows this expected signature, indicating that some process is masking the water absorption. One planet (HD 209458b) shows spectral features appearing in emission above a hot thermal continuum, indicating the likely presence of silicate clouds, and possibly more exotic compounds, at high altitudes in the planet's atmosphere.
The future launch of the James Webb Space Telescope will allow us to extend these measurements to spectra of transiting terrestrial planets in the habitable zones around lower main sequence stars.
Participation Instructions
With a Polycom....RSVP to Marco Boldt (Marco.Boldt@nasa.gov) and connect to WebEx as instructed below. If you need Polycom help during the live event, call the videoconferencing help-desk at (650) 604-6412
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Enter the meeting number: 928 244 611 Hit the "join now" button.
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Without a Polycom...There are two ways to participate:
1) You can listen to the seminar on the telephone while viewing the slides in WebEx (see WebEx instructions above). The NASA conference phone number will be displayed when joining the WebEx meeting.
2) You can watch the Realplayer webcast at: http://vanseg-1.arc.nasa.gov/2007/AB070326-01.ram and view the slides in WebEx (see WebEx instructions above) There is a 30 second delay for the webcast, so you will need to control the slides manually using the arrow buttons in WebEx. Questions for the speaker can be posted in the WebEx chat area to be answered at the end of the talk. Do not try to watch the Realplayer webcast at the same time as the Polycom or the phone. Due to the delay in the webcast, it will sound awful, unless you like dissonance.December 21, 2007
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- The NAI Director’s Seminar Series will resume in Fall 2009.