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Register a new userTransiting Exoplanet Monitoring Project (TEMP). VI. The Homogeneous Refinement of System Parameters for 39 Transiting Hot Jupiters with 127 New Light Curves
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We present 127 new transit light curves for 39 hot Jupiter systems, obtained over the span of five years by two ground-based telescopes. A homogeneous analysis of these newly collected light curves together with archived spectroscopic, photometric, and Doppler velocimetric data using EXOFASTv2 leads to a significant improvement in the physical and orbital parameters of each system. All of our stellar radii are constrained to accuracies of better than 3%. The planetary radii for 37 of our 39 targets are determined to accuracies of better than $5%$. Compared to our results, the literature eccentricities are preferentially overestimated due to the Lucy-Sweeney bias. Our new photometric observations therefore allow for significant improvement in the orbital ephemerides of each system. Our correction of the future transit window amounts to a change exceeding $10,{rm min}$ for ten targets at the time of JWSTs launch, including a $72,{rm min}$ change for WASP-56. The measured transit mid-times for both literature light curves and our new photometry show no significant deviations from the updated linear ephemerides, ruling out in each system the presence of companion planets with masses greater than $0.39 - 5.0, rm M_{oplus}$, $1.23 - 14.36, rm M_{oplus}$, $1.65 - 21.18, rm M_{oplus}$, and $0.69 - 6.75, rm M_{oplus}$ near the 1:2, 2:3, 3:2, and 2:1 resonances with the hot Jupiters , respectively, at a confidence level of $pm 1,sigma$. The absence of resonant companion planets in the hot Jupiter systems is inconsistent with the conventional expectation from disk migration.
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We present eight new light curves of the transiting extra-solar planet HAT-P-25b obtained from 2013 to 2016 with three telescopes at two observatories. We use the new light curves, along with recent literature material, to estimate the physical and orbital parameters of the transiting planet. Specifically, we determine the mid-transit times (T$_{C}$) and update the linear ephemeris, T$_{C[0]}$=2456418.80996$pm$0.00025 [$mathrm{BJD}_mathrm{TDB}$] and P=3.65281572$pm$0.00000095 days. We carry out a search for transit timing variations (TTVs), and find no significant TTV signal at the $Delta T=$80 s-level, placing a limit on the possible strength of planet-planet interactions ($mathrm{TTV_{G}}$). In the course of our analysis, we calculate the upper mass-limits of the potential nearby perturbers. Near the 1:2, 2:1, and 3:1 resonances with HAT-P-25b, perturbers with masses greater than 0.5, 0.3, and 0.5 $mathrm{M_{oplus}}$ respectively, can be excluded. Furthermore, based on the analysis of TTVs caused by light travel time effect (LTTE) we also eliminate the possibility that a long-period perturber exists with $M_{rm p}> 3000 ,mathrm{M_{J}}$ within $a=11.2,{rm AU}$ of the parent star.
The Kepler-9 system harbors three known transiting planets. The system holds significant interest for several reasons. First, the outer two planets exhibit a period ratio that is close to a 2:1 orbital commensurability, with attendant dynamical consequences. Second, both planets lie in the planetary mass desert that is generally associated with the rapid gas agglomeration phase of the core accretion process. Third, there exist attractive prospects for accurately measuring both the sky-projected stellar spin-orbit angles as well as the mutual orbital inclination between the planets in the system. Following the original textit{Kepler} detection announcement in 2010, the initially reported orbital ephemerides for Kepler-9~b and c have degraded significantly, due to the limited time base-line of observations on which the discovery of the system rested. Here, we report new ground-based photometric observations and extensive dynamical modeling of the system. These efforts allow us to photometrically recover the transit of Kepler-9~b, and thereby greatly improve the predictions for upcoming transit mid-times. Accurate ephemerides of this system are important in order to confidently schedule follow-up observations of this system, for both in-transit Doppler measurements as well as for atmospheric transmission spectra taken during transit.
A growing number (over 100!) of extra-solar planets (ESPs) have been discovered by transit photometry, and these systems are important because the transit strongly constrains their orbital inclination and allows accurate physical parameters for the planet to be derived, especially their radii. Their mass-radius relation allows us to probe their internal structure. In the present work we calculate Safronov numbers for the current sample of ESP and compare their masses and radii to current models with the goal of obtaining better constrains on their formation processe. Our calculation of Safronov numbers for the current TESP sample does show 2 classes, although about 20% lie above the formal Class I definition. These trends and recent results that argue against a useful distinction between Safronov classes are under further investigation. Mass-radius relations for the current sample of TESP are inconsistent with ESP models with very large core masses (geq 100 Moplus). Most TESP with radii near 1RJ are consistent with models with no core mass or core masses of 10 Moplus . The inflated planets, with radii geq 1.2 RJ are not consistent with current ESP models, but may lie along the lower end of models for brown dwarfs. Although such models are nascent, it is important to establish trends for the current sample of ESP, which will further the understanding of their formation and evolution.
The gaseous giant planets WASP-4b and WASP-5b are transiting 12 magnitude solar-type stars in the Southern hemisphere. The aim of the present work is to refine the parameters of these systems using high cadence VLT/FORS2 z-band transit photometry and high resolution VLT/UVES spectroscopy. For WASP-4, the new estimates for the planet radius and mass from a combined analysis of our VLT data with previously published transit photometry and radial velocities are R_p = 1.30 +0.05-0.04 R_jup and M_p = 1.21 +0.13-0.08 M_jup, resulting in a density rho_p = 0.55 +0.04-0.02 rho_jup. The radius and mass for the host star are R_s = 0.87 +0.04-0.03 R_sun and M_s = 0.85 +0.11-0.07 M_sun. Our ground-based photometry reaches 550 ppm at time sampling of ~50 seconds. Nevertheless, we also report the presence of an instrumental effect on the VLT that degraded our photometry for the WASP-5 observations. This effect could be a major problem for similar programs. Our new estimates for the parameters of the WASP-5 system are R_p = 1.09 +-0.07 R_jup, M_p = 1.58 +0.13-0.10 M_jup, rho_p = 1.23 +0.26-0.16 rho_jup, R_s = 1.03 +0.06-0.07 R_sun, and M_s = 0.96 +0.13-0.09 M_sun. The measured size of WASP-5b agrees well with the basic models of irradiated planets, while WASP-4b is clearly an `anomalously large planet.
We present the discovery of two new 10-day period giant planets from the Transiting Exoplanet Survey Satellite ($TESS$) mission, whose masses were precisely determined using a wide diversity of ground-based facilities. TOI-481 b and TOI-892 b have similar radii ($0.99pm0.01$ $rm R_{J}$ and $1.07pm0.02$ $rm R_{J}$, respectively), and orbital periods (10.3311 days and 10.6266 days, respectively), but significantly different masses ($1.53pm0.03$ $rm M_{J}$ versus $0.95pm0.07$ $rm M_{J}$, respectively). Both planets orbit metal-rich stars ([Fe/H]= $+0.26pm 0.05$ dex and [Fe/H] = $+0.24 pm 0.05$ dex, for TOI-481 and TOI-892, respectively) but at different evolutionary stages. TOI-481 is a $rm M_{star}$ = $1.14pm0.02$ $rm M_{odot}$, $rm R_{star}$ = $1.66pm0.02$ $rm R_{odot}$ G-type star ($T_{rm eff}$ = $5735 pm 72$ K), that with an age of 6.7 Gyr, is in the turn-off point of the main sequence. TOI-892, on the other hand, is a F-type dwarf star ($T_{rm eff}$ = $6261 pm 80$ K), which has a mass of $rm M_{star}$ = $1.28pm0.03$ $rm M_{odot}$, and a radius of $rm R_{star}$ = $1.39pm0.02$ $rm R_{odot}$. TOI-481 b and TOI-892 b join the scarcely populated region of transiting gas giants with orbital periods longer than 10 days, which is important to constrain theories of the formation and structure of hot Jupiters.
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