A Scientific Assessment of a New Technology Orbital Telescope (1995) / Chapter Skim
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5 SCIENCE PROJECTS
5 SCIENCE PROJECTS
Pages 47-59
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From page 47... ...
The infrared galaxy survey, though significantly enhanced by the addition of a large-format framing camera, can be carried out fruitfully so long as the baseline ATD/NTOT performs somewhere near its expected level. The Kuiper Disk survey requires the addition of a framing camera.
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From page 48... ...
Cryogenic space telescopes, such as the European Space Agency's soon-to-be-launched Infrared Space Observatory (ISO) and NASA's proposed Space Infrared Telescope Facility (SIRTF)
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From page 49... ...
(Courtesy of NASA's Space Telescope Science Institute.) redshift of z ~ 0.6, there are almost 106 background galaxies per square degree.
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From page 50... ...
(Courtesy of Peter Stockman, Space Telescope Science Institute.)
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From page 51... ...
To cover the above strip with images would require 42 paintings, each of 10 hours, for three fields for a total of 1260 hours of integration. While the primary waveband should be centered on the background minimum, observations of additional bands can broadly define the redshifts of the sample objects because of the dramatic changes in luminosity occurring across major spectral features (e.g., the H/K break at 0.4 micron)
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From page 52... ...
If additional time were available it might be valuable to obtain increased integrations in two other infrared filters at that pointing. Again, as noted above, the addition of an optical framing camera would allow I-band images to be obtained contemporaneously with each of the infrared images, thereby building up an ultradeep optical image.
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From page 53... ...
With the MST's low orbit and the resultant Earth occultation periods, it takes approximately 30 hours to obtain the necessary 5 hours of integration time. Even at quadrature, when Earth parallactic motion is zero, an object at 40 AU would move 15 arc sec (or 150 pixels on the wide-field CCDs of the WFPC2)
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From page 54... ...
With the much longer continuous viewing time of the Molniya orbit, a 4-meter telescope that undertook as a project to complete the surveying of a large piece of sky (models predict 1000 10-km objects in 1 square degree) to I = 29.5 or V ~ 30 would finally achieve a definitive picture of the mass distribution in the Kuiper Disk (Figure 5.3)
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From page 55... ...
1,000 100 10 / 1 / MST/GO / N\ \ / Theoretical Model / Archival Search T / ~ w ATD/NTOT - / 1 16 18 20 22 24 26 28 30 V magnitude FIGURE 5.3 A comparison between various searches for Kuiper Disk objects and a numerical model of the size distribution of these trans-neptunian primitive bodies. The number of Kuiper Disk objects per square degree as seen on the sky brighter than a certain V magnitude is shown as a function of that magnitude.
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From page 56... ...
A space telescope's advantages relative to those of a warm, ground-based telescope enable sensitive imaging of deeply embedded YSOs, including those still shrouded by their natal cores. This imaging would allow extremely young, embedded stars (Av ~ 50)
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From page 57... ...
High-angular-resolution observations of jets associated with YSOs spanning a range of masses and relative evolutionary states would enable characterization of jet collimation and wind-envelope interactions, and provide important insight into the role played by winds and jets during the early stages of star formation. The advantages of the ATD/NTOT would be its high angular resolution and the ability to obtain deep-infrared images of heavily obscured YSOs in their earliest evolutionary phases.
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From page 58... ...
Winds and Jets The second goal is to examine the wind and jet morphology and understand wind collimation as a function of evolutionary state. Optical (R.
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From page 59... ...
The ability to undertake this observing program does not depend on any of the enhancements suggested in Chapter 2. Rather, the decision should depend on the availability of resources to pay for the significant extra operational costs entailed in maneuvering the spacecraft to a new orbit or to a different position in its current orbit.
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