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تسجيل مستخدم جديدPrecovery of TESS Single Transits with KELT
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During the TESS prime mission, 74% of the sky area will only have an observational baseline of 27 days. For planets with orbital periods longer than 13.5 days, TESS can only capture one or two transits, and the planet ephemerides will be difficult to determine from TESS data alone. Follow-up observations of transits of these candidates will require precise ephemerides. We explore the use of existing ground-based wide-field photometric surveys to constrain the ephemerides of the TESS single-transit candidates, with a focus on the Kilodegree Extremely Little Telescope (KELT) survey. We insert simulated TESS-detected single transits into KELT light curves, and evaluate how well their orbital periods can be recovered. We find that KELT photometry can be used to confirm ephemerides with high accuracy for planets of Saturn size or larger with orbital periods as long as a year, and therefore span a wide range of planet equilibrium temperatures. In a large fraction of the sky we recover 30% to 50% of warm Jupiter systems (planet radius of 0.9 to 1.1 R_J and 13.5 < P < 50 days), 5% to 20% of temperate Jupiters (50 < P < 300 days), and 10% to 30% of warm Saturns (planet radius of 0.5 to 0.9 R_J and 13.5 < P < 50 days). The resulting ephemerides can be used for follow-up observations to confirm candidates as planets, eclipsing binaries, or other false positives, as well as to conduct detailed transit observations with facilities like JWST or HST.
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NASAs Transiting Exoplanet Survey Satellite (TESS) mission is expected to discover hundreds of planets via single transits first identified in their light curves. Determining the orbital period of these single transit candidates typically requires a
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We present results of a study on identifying circumbinary planet candidates that produce multiple transits during one conjunction with eclipsing binary systems. The occurrence of these transits enables us to estimate the candidates orbital periods, w
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amplitude of $234^{+43}_{-44}$ ppm and a secondary eclipse depth of $371^{+47}_{-49}$ ppm. We also measured a marginal eastward offset in the dayside hotspot of $18.3^circpm7.4^circ$ relative to the substellar point. We detected a strong phase curve signal attributed to ellipsoidal distortion of the host star, with an amplitude of $399pm19$ ppm. Our results are roughly consistent with the Spitzer phase curves of KELT-1b (Beatty et al. 2019), but the TESS eclipse depth is deeper than expected. Our cloud-free 1D models of KELT-1bs dayside emission are unable to fit the full combined eclipse spectrum. Instead, the large TESS eclipse depth suggests that KELT-1b may have a significant dayside geometric albedo of $mathrm{A}_mathrm{g}sim0.5$ in the TESS bandpass, which would agree with the tentative trend between equilibrium temperature and geometric albedo recently suggested by Wong et al. 2020. We posit that if KELT-1b has a high dayside albedo, it is likely due to silicate clouds (Gao et al. 2020) that form on KELT-1bs nightside (Beatty et al. 2019, Keating et al. 2019) and are subsequently transported onto the western side of KELT-1bs dayside hemisphere before breaking up.
We present the discoveries of KELT-25b (TIC 65412605, TOI-626.01) and KELT-26b (TIC 160708862, TOI-1337.01), two transiting companions orbiting relatively bright, early A-stars. The transit signals were initially detected by the KELT survey, and subs
equently confirmed by textit{TESS} photometry. KELT-25b is on a 4.40-day orbit around the V = 9.66 star CD-24 5016 ($T_{rm eff} = 8280^{+440}_{-180}$ K, $M_{star}$ = $2.18^{+0.12}_{-0.11}$ $M_{odot}$), while KELT-26b is on a 3.34-day orbit around the V = 9.95 star HD 134004 ($T_{rm eff}$ =$8640^{+500}_{-240}$ K, $M_{star}$ = $1.93^{+0.14}_{-0.16}$ $M_{odot}$), which is likely an Am star. We have confirmed the sub-stellar nature of both companions through detailed characterization of each system using ground-based and textit{TESS} photometry, radial velocity measurements, Doppler Tomography, and high-resolution imaging. For KELT-25, we determine a companion radius of $R_{rm P}$ = $1.64^{+0.039}_{-0.043}$ $R_{rm J}$, and a 3-sigma upper limit on the companions mass of $sim64~M_{rm J}$. For KELT-26b, we infer a planetary mass and radius of $M_{rm P}$ = $1.41^{+0.43}_{-0.51}$ $M_{rm J}$ and $R_{rm P}$ = $1.940^{+0.060}_{-0.058}$ $R_{rm J}$. From Doppler Tomographic observations, we find KELT-26b to reside in a highly misaligned orbit. This conclusion is weakly corroborated by a subtle asymmetry in the transit light curve from the textit{TESS} data. KELT-25b appears to be in a well-aligned, prograde orbit, and the system is likely a member of a cluster or moving group.
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