Photometric Defocus Observations of Transiting Extrasolar Planets
We have carried out photometric follow-up observations of bright transiting extrasolar planets using the CbNUOJ 0.6 m telescope. We have tested the possibility of obtaining high photometric precision by applying the telescope defocus technique, allowing the use of several hundred seconds in exposu...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Korean Space Science Society (KSSS)
2015-03-01
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| Series: | Journal of Astronomy and Space Sciences |
| Subjects: | |
| Online Access: | http://ocean.kisti.re.kr/downfile/volume/kosss/OJOOBS/2015/v32n1/OJOOBS_2015_v32n1_21.pdf |
| Summary: | We have carried out photometric follow-up observations of bright transiting extrasolar planets using the CbNUOJ 0.6
m telescope. We have tested the possibility of obtaining high photometric precision by applying the telescope defocus
technique, allowing the use of several hundred seconds in exposure time for a single measurement. We demonstrate that
this technique is capable of obtaining a root-mean-square scatter of sub-millimagnitude order over several hours for a V
~10 host star, typical for transiting planets detected from ground-based survey facilities. We compared our results with
transit observations from a telescope operated in in-focus mode. High photometric precision was obtained due to the
collection of a larger amount of photons, resulting in a higher signal compared to other random and systematic noise
sources. Accurate telescope tracking is likely to further contribute to lowering systematic noise by exposing the same pixels
on the CCD. Furthermore, a longer exposure time helps reduce the effect of scintillation noise which otherwise has a
significant effect for small-aperture telescopes operated in in-focus mode. Finally we present the results of modelling four
light-curves in which a root-mean-square scatter of 0.70 to 2.3 milli-magnitudes was achieved. |
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| ISSN: | 2093-5587 2093-1409 |