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Understanding Hot Jupiters with the DEdicated MONitor of EXotransits and Transients (DEMONEXT)

Villanueva, Steven, Jr.
http://rave.ohiolink.edu/etdc/view?acc_num=osu1531488771229221

Abstract Details

2018, Doctor of Philosophy, Ohio State University, Astronomy.
We present results for the misaligned Hot Jupiter, XO-4b, taken with the decommissioned DEdicated MONitor of EXotransits (DEMONEX) telescope, as a proof-of-concept for the upcoming DEdicated MONitor of EXotransits and Transients (DEMONEXT) telescope. We combine these data with archival light curves and archival radial velocity measurements to derive the XO-4 host star mass $M_{*}=1.293_{-0.029}^{+0.030}~\msun$ and radius $R_{*}=1.554_{-0.030}^{+0.042}~\rsun$ as well as the XO-4b planet mass $M_{P}=1.615_{-0.099}^{+0.10}~\mj$ and radius $R_{P}=1.317_{-0.029}^{+0.040}~\rj$ and a refined ephemeris of $P=4.1250687\pm0.0000024$~days and $T_{0}=2454758.18978\pm0.00024~\bjdtdb$. We include archival Rossiter-McLaughlin measurements of XO-4 to infer the stellar spin-planetary orbit alignment $\lambda=-40.0_{-7.5}^{+8.8}$~degrees. In preparation for DEMONEXT observations, we test the effects of including various detrend parameters, theoretical and empirical mass-radius relations, and Rossiter-McLaughlin models. We infer that detrending against CCD position and time or airmass can improve data quality, but can have significant effects on the inferred values of many parameters --- most significantly $R_{P}/R_{*}$ and the observed central transit times $T_{C}$. In the case of $R_{P}/R_{*}$ we find that the systematic uncertainty due to detrending can be three times that of the quoted statistical uncertainties. The choice of mass-radius relation has little effect on our inferred values of the system parameters, but the choice of Rossiter-McLaughlin models can have significant effects of the inferred values of $v\sin{I_{*}}$ and the stellar spin-planet orbit angle $\lambda$. We report on the design and first two years of operations of the newly commissioned DEMONEXT telescope. DEMONEXT is a 20 inch (0.5-m) robotic telescope using a PlaneWave CDK20 telescope on a Mathis instruments MI-750/1000 fork mount. DEMONEXT is equipped with a $2048\times2048$\,pixel Finger Lakes Instruments (FLI) detector, a 10-position filter wheel with an electronic focuser and $B$, $V$, $R$, $I$, $g'$, $r'$, $i'$, $z'$, and clear filters. DEMONEXT operates in a continuous observing mode and achieves 2--4\,mmag raw, unbinned, precision on bright $V<13$ targets with 20--120\,second exposures, and 1\,mmag precision achieved by binning on 5--6 minute timescales. DEMONEXT maintains sub-pixel ($<0.5$~pixels) target position stability on the CCD over 8 hours in good observing conditions, with degraded performance in poor weather ($<1$~pixel). DEMONEXT achieves 1--10\% photometry on single-epoch targets with $V<17$ in 5 minute exposures, with detection thresholds of $V\approx21$. The DEMONEXT automated software has produced over 300 planetary candidate transit light curves for the KELT collaboration, and over 100 supernovae and transient light curves for the ASAS-SN supernovae group in the first two years of operations. DEMONEXT has also observed for a number of ancillary science projects including Galactic microlensing, active galactic nuclei, stellar variability, and stellar rotation. Finally, we present a semi-analytic estimate of the expected yield of single-transit planets from TESS as possible future targets for DEMONEXT. We use the TESS Candidate Target List 6 (CTL-6) as an input catalog of over 4 million sources. We predict that from the 200,000 stars selected to be observed with the high-cadence postage stamps with the highest CTL-6 priority, there will be 241 single-transit events caused by planets detectable at a signal-to-noise ratio of SNR$\ge7.3$. We find a lower limit of an additional 977 events caused by single-transit planets in the full frame images (FFI); this is a lower limit because the CTL-6 is incomplete below a TESS magnitude of $T>12$. Of the single-transit events from the postage stamps and FFIs, 1091/1218 will have transit depths deeper than 0.1\%, and will thus be amenable for photometric follow-up from the ground from telescopes like DEMONEXT. 1195/1218 will have radial velocity signals greater than 1~m/s, measurable from current ground-based telescopes. We estimate that the periods of 146 single transits will be constrained to better than 10\% using the TESS photometry assuming circular orbits. We find that the number of planets detected by TESS in the postage stamps with periods $P>25$~days will be doubled by including single-transiting planets, while the number of planets with $P>250$~days will be increased by an order of magnitude. We predict 79 habitable zone planets from single-transits, with 18 orbiting FGK stars.
B. Scott Gaudi (Advisor)
Richard Pogge (Advisor)
Laura Lopez (Committee Member)
156 p.
Astronomy; Astrophysics

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Citations

  • Villanueva, Jr., S. (2018). Understanding Hot Jupiters with the DEdicated MONitor of EXotransits and Transients (DEMONEXT) [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1531488771229221

    APA Style (7th edition)

  • Villanueva, Jr., Steven. Understanding Hot Jupiters with the DEdicated MONitor of EXotransits and Transients (DEMONEXT). 2018. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1531488771229221.

    MLA Style (8th edition)

  • Villanueva, Jr., Steven. "Understanding Hot Jupiters with the DEdicated MONitor of EXotransits and Transients (DEMONEXT)." Doctoral dissertation, Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1531488771229221

    Chicago Manual of Style (17th edition)

osu1531488771229221
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This open access ETD is published by The Ohio State University and OhioLINK.