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Finding Mars-Sized Planets in Inner Orbits of Other Stars by PhotometryHigh precision photometry from a spaceborne telescope has the potential of discovering sub-earth sized inner planets. Model calculations by Wetherill indicate that Mars-sized planets can be expected to form throughout the range of orbits from that of Mercury to Mars. While a transit of an Earth-sized planet causes a 0.084% decrease in brightness from a solar-like star, a transit of a planet as small as Mars causes a flux decrease of only 0.023%. Stellar variability will be the limiting factor for transit measurements. Recent analysis of solar variability from the SOLSTICE experiment shows that much of the variability is in the UV at <400 nm. Combining this result with the total flux variability measured by the ACRIM-1 photometer implies that the Sun has relative amplitude variations of about 0.0007% in the 17-69 pHz bandpass and is presumably typical for solar-like stars. Tests were conducted at Lick Observatory to determine the photometric precision of CCD detectors in the 17-69 pHz bandpass. With frame-by-frame corrections of the image centroids it was found that a precision of 0.001% could be readily achieved, corresponding to a signal to noise ratio of 1.4, provided the telescope aperture was sufficient to keep the statistical noise below 0.0006%. With 24 transits a planet as small as Mars should be reliably detectable. If Wetherill's models are correct in postulating that Mars-like planets are present in Mercury-like orbits, then a six year search should be able to find them.
Document ID
20020034619
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Borucki, W.
(NASA Ames Research Center Moffett Field, CA United States)
Cullers, K.
(NASA Ames Research Center Moffett Field, CA United States)
Dunham, E.
(NASA Ames Research Center Moffett Field, CA United States)
Koch, D.
(NASA Ames Research Center Moffett Field, CA United States)
Mena-Werth, J.
(Nebraska Univ. Kearney, NE United States)
Cuzzi, Jeffrey N.
Date Acquired
August 20, 2013
Publication Date
January 1, 1995
Subject Category
Astronomy
Meeting Information
Meeting: 27th Annual Meeting of the Division for Planetary Sciences
Location: Mauna Lani, HI
Country: United States
Start Date: October 9, 1995
End Date: October 13, 1995
Sponsors: Lunar and Planetary Inst.
Funding Number(s)
PROJECT: RTOP 186-06-01-04
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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