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Thomas Geballe, 3-5 µm Astronomy from Antarctica
The extremely cold environment at the South Pole makes it a remarkably advantageous location for ground-based infrared astronomy, especially from the long wavelength end of the 2µm (K) atmospheric window through the 5µm (M) window. I will review the prospects for high sensitivity imaging and spectroscopy at the South Pole, making comparisons between the pole and other well-known astronomical sites, comparing the performance of the proposed 2m class telescope with existing telescopes elsewhere, and summarizing some of the key science that can be done from Antarctica.
Paolo Persi, A Mid-Infrared Survey of the Chameleon Dark Clouds Complex
The southern hemisphere Chameleon star formation region consist of at least five dark clouds. This complex is ideal for the study of low-mass young stellar objects given its proximity to the sun (D=140-180 pc) and high Galactic latitude. The results of a limited survey covering approximately 1 sq deg of the three main clouds (Cha I, Cha II and Cha III), obtained with ISOCAM at 6.7 and 14.3 micron, are presented. The importance to extend the mid-IR survey at all the complex region from the Antarctica site is discussed.
Adam Burgasser, Studying L and T Dwarfs at AIRO
The enhanced infrared sensitivities and potential for long-term and deep observations from AIRO makes it aptly suited for the study of the coolest brown dwarfs and low-mass stars, in particular the recently identified L and T dwarf classes. I will discuss a number of potential investigations ideally suited for AIRO, including surveys of young clusters and the Solar Neighborhood, monitoring observations to search for weather or activity, characterization of spectral properties and the chemical evolution of brown dwarf atmospheres, and the discovery of even cooler classes of objects currently unknown.
Almost 80 extrasolar giant planets have been discovered around nearby sun-like stars. Little is known about these planets aside from their minimum mass and orbital parameters. Even though the extrasolar planets cannot be spatially resolved from their parent stars, many useful studies can be made in the combined light of the planet-star system. In November 2001, for the first time ever, an extrasolar planet atmosphere was detected of the transiting planet HD209458b in a very narrow wavelength region. A variety of atmosphere detection methods at a variety of wavelengths are needed to learn about the physical properties of extrasolar giant planets. The most useful science from AIRO would be determining the day- and night-side temperatures of transiting extrasolar giant planets by measuring the primary and secondary eclipses. Other useful science would include photometry and spectroscopy of molecular signatures at 3—5 microns.
Ian Glass, AGB Variables in the LMC and Elsewhere
I discuss firstly LMC Miras and their period luminosity relation, Similar data are available for the Baade's Window clear fields near the Galactic Center and for galactic globular clusters. Mass-loss is not peculiar to Miras but also occurs in semi-regular variables. This has become evident from cross-correlating mid-IR data from ISOGAL with the MACHO database. Mass-losing SRs are interspersed with the Miras in the J-K, K color-magnitude and the J-H, H-K color-color diagrams from 2MASS. In the LMC Wood has shown that AGB variables lie along several sequences in the P-L diagram. I look at the LMC and Galactic variables in the same diagram.
Michael Jura, Reasons for Studying Time-Variable Infrared Emission from Evolved Red Giants
The mass loss mechanism for some red giants is closely coupled to the pulsations of the stars. At least in the case of the nearby semiregular, L2 Pup, the mass loss is highly asymmetric. This asymmetry may be partly explained by non-radial pulsations. The data from the DIRBE mission seem to support this hypothesis. The value of well-sampled infrared light curves at several wavelengths is discussed.
Joel Kastner, Nearby Young Stellar Associations
Recent years have seen the identification of several groups of young stars (ages 5-30 Myr) within 100 PC of the Sun. These nearby "post-T Tauri'' stars, once identified, are well suited to high spatial and spectral resolution studies of stellar and circumstellar environments at the epoch of Jovian planet formation. Most of the recently identified, nearby associations are located in the southern sky, and the proposed Antarctic Infrared Observatory (AIRO) would make important contributions to their study. I summarize progress in identifying nearby stellar associations, present highlights of recent observations of individual stars in these associations, and prognosticate on the potential role(s) that might be played by AIRO.
Charles Lada, Infrared Imaging of Embedded Clusters
In this talk I will illustrate a few examples of how infrared imaging surveys
can address important problems in star and planet formation research. In particular
I will discuss the importance of ground-based L-band observations for investigating
the evolution of proto-planetary, circumstellar disks and for mapping protostellar
populations in molecular clouds.
Xander Tielens, PAHs: An astronomer's tool
The near-infrared spectrum of many objects is dominated by IR emission
features at 3.3, 6.2, 7.7, 8.6, and 11.3 µm. These features are
generally ascribed to IR vibrational relaxation of UV pumped Polycyclic Aromatic
Hydrocarbon molecules. Analysis of the data obtained by the Short Wavelength
Spectrometer on board of the Infrared Space Observatory has revealed spectral
and spatial variations in the emission characteristics of the interstellar mid-IR
spectrum. Clearly, the carriers are sensitive to the local physical conditions
and this provides a powerful tool for identifying specific molecular species.
However, in this talk, I will focus on using the PAH features as
tracers of astrophysical processes. The emphasis will be on highlighting the
key questions that have to be addressed before PAHs can become the astronomer's
tool of choice.
Christine Joblin, Coupling between PAHs and Hydrogen (H,H2) in Space and in the Laboratory
After the results of the Infrared Space Observatory, polycyclic
aromatic hydrocarbons (PAHs) remain the best candidates to account for the Aromatic
IR bands (AIBs) at 3.3, 6.2, 7.7, 8.6, 11.3 and 12.7µm. Still, the identification
of specific species has not been possible. It is probable that the candidates
which are usually
studied in the laboratory are not those of astrophysical interest. Interstellar
PAHs are submitted to UV photons that can lead to photodissociation. On the
other hand, they can react with the gas, in particular with H and H2.
Trying to understand the photophysical and chemical evolution of PAHs in the
interstellar medium would certainly help to identify the carriers of the AIBs.
To address this topic, I will present results of a new experimental
setup dedicated to interstellar astrochemistry, PIRENEA. The experiment allows
to approach the conditions of isolation and low temperature that prevail in
space and therefore to study physical and chemical processes on long timescales.
Evidence for a coupling between PAHs and hydrogen has also been searched for
in the environment of the young massive star S106-IR. I will present the observations
performed at the CFH telescope using the C10µ camera and the Fourier transform
spectrometry imager BEAR.
Jill Rathborne, The South Pole Thermal InfraRed Experiment: Studies of Massive Star Formation
The implementation of a thermal Infrared (IR) imager on
the Antarctic plateau would enable us to observe processes normally `blocked'
by the thermal background emission from the Earth's atmosphere at temperate
sites. Observations with such an imager would allow us to uncover the deepest
objects and intense interactions occurring in star forming molecular cloud complexes.
The 60cm SPIREX/Abu telescope, located at the South Pole,
was the first prototype for a thermal IR imager in Antarctica. Observations
over two winter seasons achieved remarkable high resolution, wide field images
of several star forming regions. These images reveal information crucial to
understanding star formation, and combined with ground- and space-based observations
of other wavelength regimes, allow us to obtain a more complete picture of the
star formation process.
The thermal-IR data from SPIREX/Abu will be discussed in combination
with near- and mid-IR data for the star forming regions in the Carina Nebula
and NGC 6334. The many photodissociation regions (PDRs) within these regions
are clearly evident in the images, along with several newly discovered sites
of ongoing star formation.
The SPIREX project was a collaboration between the Joint Australian
Centre for Astrophysical Research in Antarctica (JACARA), the Center for Astrophysical
Research in Antarctica (CARA) and the National Optical Astronomy Observatories
(NOAO).
David Koerner, Protoplanetary Disks in the Infrared
Conclusive evidence for circumstellar disks around young stars is a key legacy of the original opening of an infrared window in astronomy. Unresolved infrared emission from young stars was understood early on to originate from circumstellar dust. Imaging at many wavelengths has confirmed a disk interpretation for dust detected from both classical T Tauri stars and older "Vega-like" stars. A productive era of disk studies is now in full swing; the detailed properties of disks are emerging together with an understanding of their importance to planet formation. Nevertheless, the relationship between these two disk populations remains unclear. Do comparatively massive and gas-rich accretion disks generate planetary systems by evolving through a stage represented by Vega-like disks? The answer to this question poses primarily an observational challenge in sensitivity. The incidence of intermediate-mass disks around Sun-like stars is not well known, since they radiate below the levels of earlier infrared surveys at the distance of the nearest molecular clouds (~150 PC). Moreover, many Vega-like systems have not been imaged, though they could be easily resolved with modest apertures if sensitivity was available to detect their tenuous dust reservoirs dust at stellocentric distances of 50-100 AU. A modest-aperture infrared telescope at a highly favorable infrared site could make great strides in disk evolution by imaging detail in nearby Vega-type disks and by measuring the excess infrared flux from stars in molecular clouds that have evolved beyond the classical T Tauri phase.
Observing conditions at the South Pole have probably been
better characterized than at any other site on earth. The benefits are now well
established, and include greatly reduced near- and mid-infrared sky brightness,
improved atmospheric transmission, and a unique atmospheric turbulence profile
with almost zero turbulence above the lowest 200 meters of the atmosphere. We
will review these findings, and discuss their implications for the science goals
of an IR telescope.
The site testing work is continuing, with a view to better
understanding the residual infrared sky emission and the nature of the atmospheric
turbulence. Autonomous experiments are now also currently operating at Dome
C. Plans are well advanced to extend these experiments, and to study even higher
altitude sites such as Vostok and Dome A.
Tony Travouillon, Seeing and Other Turbulence Derivatives
During the last decade, a lot of work has been done to measure
and understand the seeing at the South Pole. We review the current understanding
of the unique turbulence profile at the South Pole. We investigate the origin
of the seeing and introduce the latest seeing and aberration tool: The ADIMM
(Antarctic Differential Motion Monitor).
Maurizio Candidi, The status and perspectives of the French-Italian base CONCORDIA
The status of the construction of the French-Italian base at Dome-C, CONCORDIA, is described, and the perspective developments outlined.
We briefly outline the main characteristics of the IRAIT
project, based on a 80-cm reflector with a mid-infrared camera, to be placed
at the Italo-French base of Dome C. We show how, in the exceptional atmospheric
conditions of the Antarctic plateau, several programs in infrared astronomy
become feasible, and how, despite the small diameter of the instrument, the
expected performances are already quite interesting, and suitable to give relevant
contributions to various crucial astrophysical problems. These include the last
stages of low-mass and intermediate-mass star evolution in southern subsystems
of our Galaxy and in the Magellanic Clouds (especially for the understanding
of mass loss phenomena), as well as star formation and the early stages of stellar
evolution. We also address the possibilities of affording a few extragalactic
projects in a survey-like mode of operation.
Al Harper, Future Telescopes
James Lloyd, Differential Astrometric Interferometery from the South Pole
The low infrared background and high atmospheric transparency
are the principal advantages of Antarctic Plateau sites for astronomy. However,
the seeing (between one and three arcseconds) negates much of the sensitivity
improvements that the Antarctic atmosphere offers in the visible near-IR, compared
to mid-latitude sites such as Mauna Kea or Cerro Paranal. The seeing at mid-latitude
sites, though smaller in amplitude, is dominated by turbulence at altitudes
of 10 to 20 km. Over the Antarctic plateau, virtually no high altitude turbulence
is present in the winter. The mean square error for an astrometric measurement
with a dual-beam, differential astrometric interferometer in the very narrow
angle regime is proportional to the integral of h2 CN2(h).
Therefore, sites at which the turbulence occurs only at low altitudes offer
large gains in astrometric precision. A modest interferometer at the South Pole
can achieve 10 µas differential astrometry 300 times faster than a comparable
interferometer at a good mid-latitude site, in median conditions. Science programs
that would benefit from such an instrument include planet detection and orbit
determination, astrometric observation of stars microlensed by dark matter candidates,
and studies of stars and the dynamics stellar systems.
James Jackson, AIRO: The Antarctic Infrared Observatory
We aim to exploit the unique conditions on the Antarctic
Plateau by establishing a new permanent national facility, the Antarctic Infrared
Observatory. AIRO will be optimized for wide-field imaging in the thermal infrared.
The unique conditions in Antarctica provide several advantages, such as extremely
low thermal backgrounds, long periods of darkness, and very stable skies. Because
Antarctic telescopes require an aperture of only ~2 meters to achieve similar
sensitivities as the 8-meter telescopes, they are very cost-effective. Moreover,
upgrades to mid-infrared, spectroscopic, or polarimatric instruments can be
implemented rapidly and relatively cheaply. The large field of view and excellent
sensitivity of AIRO are optimally suited for the first deep, widefield surveys
and temporal variability studies in the 3 to 5 micron waveband. With this unique
capability, AIRO will make important observations of protoplanetary disks, the
Magellanic clouds, brown dwarfs, evolved stars, and star-forming regions.
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