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Photometric Defocus Observations of Transiting Extrasolar Planets
Hinse, Tobias C.,Han, Wonyong,Yoon, Joh-Na,Lee, Chung-Uk,Kim, Yong-Gi,Kim, Chun-Hwey The Korean Space Science Society 2015 Journal of Astronomy and Space Sciences Vol.32 No.1
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.
Tobias C. Hinse,김우균,안상현,이재근,박준형,이영우,정우정,우상민 한국천문학회 2017 天文學論叢 Vol.32 No.3
We give a detailed description of the installation and operation of a double-station meteor detectionsystem which formed part of a research & education project between Korea Astronomy Space ScienceInstitute (KASI) and Daejeon Science Highschool. A similar system is currently not existing in SouthKorea. A total of six light-sensitive CCD cameras were installed with three cameras at SOAO and threecameras at BOAO observatory. A double-station observation of a meteor event enables the determinationof the three-dimensional heliocentric orbit in space. This project was initiated in response to the Jinjureball event in March 2014. The cameras were installed in October/November 2014. The two stationsare identical in hardware as well as software. Each station employes sensitive \Watec-902H2" cameras incombination with relatively fast f/1.2 lenses. Various elds of views were used for measuring di erencesin detection rates of meteor events. We employed the SonotaCo UFO software suite for meteor detectionand their subsequent analysis. The system setup as well as installation/operation experience is describedand rst results are presented. We also give a brief overview of historic as well as recent meteor (fall)detections in South Korea. For more information please consult http://meteor.kasi.re.kr.
Photometric Defocus Observations of Transiting Extrasolar Planets
Tobias C. Hinse,Wonyong Han,Joh-Na Yoon,Chung-Uk Lee,Yong-Gi Kim,Chun-Hwey Kim 한국우주과학회 2015 Journal of Astronomy and Space Sciences Vol.32 No.1
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.
The Dynamical History of 2060 Chiron and Its Proposed Ring System
Wood, Jeremy,Horner, Jonti,Hinse, Tobias C.,Marsden, Stephen C. American Astronomical Society 2018 The Astronomical journal Vol.155 No.1
<P>The surprising discovery of a ring system around the Centaur 10199 Chariklo in 2013 led to a reanalysis of archival stellar occultation data for the Centaur 2060 Chiron by Ortiz et al. One possible interpretation of that data is that a system of rings exists around Chiron. In this work, we study the dynamical history of the proposed Chiron ring system by integrating nearly 36,000 clones of the Centaur backward in time for 100 Myr under the influence of the Sun and the four giant planets. The severity of all close encounters between the clones and planets while the clones are in the Centaur region is recorded, along with the mean time between close encounters. We find that severe and extreme close encounters are very rare, making it possible that the Chiron ring system has remained intact since its injection into the Centaur region, which we find likely occurred within the past 8.5 Myr. Our simulations yield a backward dynamical half-life for Chiron of 0.7 Myr. The dynamical classes of a sample of clones are found. It is found that, on average, the Centaur lifetimes of resonance hopping clones are twice those of random-walk clones because of resonance sticking in mean motion resonances. In addition, we present MEGNO and chaotic lifetime maps of the region bound by 13 au <= a <= 14 au and e <= 0.5. We confirm that the current mean orbital parameters of Chiron are located in a highly chaotic region of a - e phase space.</P>