Report - School of Physics

siting extra-solar planets are expected to be found in the next several years with
both ground-based and space-based telescopes (including Kepler). The short wavelength
end is especially important for detecting scattered light and characterising
planetary albedos. In particular, NIRSpec’s long-slit configuration is essential for
these observations. Thus JWST, even more so than HST, has considerable potential
for follow-up observations of transiting systems discovered by other methods,
for example by Kepler. This issue is developed further in Section 4.
Spitzer: Spitzer (ex-SIRTF, http://www.spitzer.caltech.edu/) is an 85 cm aperture,
liquid helium cooled telescope in an Earth-trailing heliocentric orbit. Launched in
August 2003, it has a projected lifetime (minimum) of 2.5 years with a goal of
5 years or more. The instrument complement provides the capabilities for imaging/photometry
from 3–180 µm, spectroscopy from 5–40 µm and spectrophotometry
from 50–100 µm. Spitzer’s expected contribution to the field of exo-planet research
lies in its ability to measure excess radiation from dust disks over the critical midinfrared
wavelength range. The imaging capability is determined by the diffraction
limit of the relatively small telescope (1.5 arcsec at 6.5 µm). The sensitivity, however,
allows the detection of dust masses to below the mass in small grains inferred
in our Kuiper Belt (6 × 10 22 gm) surrounding a Solar-type star at 30 pc.
One of the six Legacy Programs is concerned explicitly with the formation and
evolution of planetary systems (see: ‘The Formation and Evolution of Planetary
Systems: Placing Our Solar System in Context’ http://feps.as.arizona.edu/). This
uses 350 hr of photometric and spectroscopic Spitzer time to detect and characterise
the dust disk emission from two samples of solar-like stars, the first consisting of
objects within 50 pc spanning an age range from 100–3000 Myr and the second
containing objects between 15–180 pc spanning ages from 3–100 Myr.
The first call for Guest Observer programmes resulted in 8 accepted exo-planet
proposals out of a total of 202 programmes in all subject areas. This includes one
to characterise the atmosphere and evolution of the transiting extra-solar planet
HD 209458b. The Cycle 2 call for proposals had a deadline of 12 Feb 2005. The
accepted Guest Observer proposals related to exo-planets were:
* Ultracool Brown Dwarfs and Massive Planets Around Nearby White Dwarfs
* The SIM/TPF Sample: Comparative Planetology of Neighbouring Solar Systems
* Evolution of Gaseous Disks and Formation of Giant and Terrestrial Planets
* Searching the Stellar Graveyard for Planets and Brown Dwarfs with SST
* A Search for Planetary Systems around White Dwarf Merger Remnants
* Characterising the Atmosphere and Evolution of HD 209458b
* Survey for Planets and Exozodiacal Dust Around White Dwarfs
* Mineralogy, Grain Growth and Dust Settling in Brown Dwarf Disks
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