The Transit Light Curve Project. III. Tres Transits of TrES‐1

Winn, Joshua N.; Holman, Matthew J.; Roussanova, Anna

doi:10.1086/510834

Cited by 106 publications

(140 citation statements)

References 51 publications

(62 reference statements)

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“…We fit both Equation (1) and the transit curve to the first 10 hours of data simultaneously using a Markov Chain Monte Carlo (MCMC) method (e.g., Tegmark et al 2004;Ford 2005;Winn et al 2007a;Burke et al 2007). We exclude the first 30 minutes of data from our fit, as the ramp is particularly steep during this time, and set the uncertainties on individual points equal to the rms variance of the time series between 0.8 and 1.0 days after the start of the observations (this is the middle of the time There is still a small ramp at early times, but its amplitude is smaller than the equivalent ramp with no preflash and the ramp converges to a constant value within the first 10 hr of observations.…”

Section: Eclipse Fitsmentioning

confidence: 99%

THE 8 μm PHASE VARIATION OF THE HOT SATURN HD 149026b

Knutson

Charbonneau

Cowan

et al. 2009

ApJ

127

111

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We monitor the star HD 149026 and its Saturn-mass planet at 8.0 μm over slightly more than half an orbit using the Infrared Array Camera on the Spitzer Space Telescope. We find an increase of 0.0227% ± 0.0066% (3.4σ significance) in the combined planet-star flux during this interval. The minimum flux from the planet is 45% ± 19% of the maximum planet flux, corresponding to a difference in brightness temperature of 480 ± 140 K between the two hemispheres. We derive a new secondary eclipse depth of 0.0411% ± 0.0076% in this band, corresponding to a dayside brightness temperature of 1440 ± 150 K. Our new secondary eclipse depth is half that of a previous measurement (3.0σ difference) in this same bandpass by Harrrington et al. We re-fit the Harrrington et al. data and obtain a comparably good fit with a smaller eclipse depth that is consistent with our new value. In contrast to earlier claims, our new eclipse depth suggests that this planet's dayside emission spectrum is relatively cool, with an 8 μm brightness temperature that is less than the maximum planet-wide equilibrium temperature. We measure the interval between the transit and secondary eclipse and find that that the secondary eclipse occurs 20.9 +7.2 −6.5 minutes earlier (2.9σ ) than predicted for a circular orbit, a marginally significant result. This corresponds to e cos (ω) = −0.0079 +0.0027 −0.0025 , where e is the planet's orbital eccentricity and ω is the argument of pericenter.

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Section: Eclipse Fitsmentioning

confidence: 99%

THE 8 μm PHASE VARIATION OF THE HOT SATURN HD 149026b

Knutson

Charbonneau

Cowan

et al. 2009

ApJ

127

111

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“…In the following transit timing analysis we included several published mid-transit observations, by Charbonneau et al (2005), Winn et al (2007) and Hrudková et al (2009) for TrES-1 (Table 2), and for TrES-2 by Holman et al (2007) (Table 3). We considered only O-C times with errors below 60 s, which led to the rejection of some O-C values from Charbonneau et al (2005).…”

Section: Light Curve Fittingmentioning

confidence: 99%

Transit timing analysis of the exoplanets TrES-1 and TrES-2

Deeg

Alonso

Belmonte

et al. 2009

A&A

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Aims. The aim of this work is a detailed analysis of transit light curves from TrES-1 and TrES-2, obtained over a period of three to four years, in order to search for variabilities in observed mid-transit times and to set constraints on the presence of additional third bodies. Methods. Using the IAC 80 cm telescope, we observed transits of TrES-1 and TrES-2 over several years. Based on these new data and previously published work, we studied the observed light curves and searched for variations in the difference between observed and calculated (based on a fixed ephemeris) transit times. To model possible transit timing variations, we used polynomials of different orders, simulated O-C diagrams corresponding to a perturbing third mass, and we used sinusoidal fits. For each model we calculated the χ 2 residuals and the false alarm probability (FAP).Results. For TrES-1, we can exclude planetary companions (>1 M ⊕ ) in the 3:2 and 2:1 MMRs having high FAPs based on our transit observations from the ground. Likewise, a light time effect caused, e.g., by a 0.09 M mass star at a distance of 7.8 AU is possible. As for TrES-2, we find a better ephemeris of T c = 2 453 957.63512(28) + 2.4706101(18) × Epoch and a good fit for a sine function with a period of 0.2 days, compatible with a moon around TrES-2 and an amplitude of 57 s, but it is not a uniquely low χ 2 value that would indicate a clear signal. In both cases, TrES-1 and TrES-2, we are able to put upper constraints on the presence of additional perturbers masses. We also conclude that any sinusoidal variations that might be indicative of exomoons need to be confirmed with higher statistical significance by further observations, noting that TrES-2 is in the field-of-view of the Kepler Space Telescope.

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“…After normalization of the flux we fit a theoretical light curve using the system parameters by Winn et al (2007) (Table 4) Table 5. The transit of epoch 40.5 (forced e = 0) according to the ephemeris given by Winn et al (2007) is even a secondary transit observed with the Spitzer Space Telescope by Charbonneau et al (2005). With all available transit times in Table 5 we determined the transit and secondary-eclipse timing residuals for TrES-1.…”

Section: Determination Of the Midtransit Timementioning

confidence: 99%

“…With all available transit times in Table 5 we determined the transit and secondary-eclipse timing residuals for TrES-1. The calculated times (using the ephemeris of Winn et al 2007) have been subtracted from the observed times. The resulting O-C is shown in Fig.…”

Section: Determination Of the Midtransit Timementioning

confidence: 99%

“…The data points from the University Observatory Jena are shown in gray. The dashed and best-fitting (solid) line shows the ephemeris given by Winn et al (2007) and the updated ephemeris given in equation 5, respectively. Winn et al (2007) b from Charbonneau et al (2005) c from Alonso et al (2004) d from various observers collected in Exoplanet Transit Database, http://var.astro.cz/ETD e from Winn et al (2007) f from Narita et al (2007) g from Hrudkova et al (2009) …”

Section: Determination Of the Midtransit Timementioning

confidence: 99%

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Planetary transit observations at the University Observatory Jena: XO‐1b and TrES‐1

et al. 2009

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We report on observations of transit events of the transiting planets XO-1b and TrES-1 with a 25 cm telescope of the University Observatory Jena. With the transit timings for XO-1b from all 50 available XO, SuperWASP, Transit Light Curve (TLC)-Project-and Exoplanet Transit Database (ETD)-data, including our own I-band photometry obtained in March 2007, we find that the orbital period is P = (3.941501 ± 0.000001) d, a slight change by ∼3 s compared to the previously published period. We present new ephemeris for this transiting planet. Furthermore, we present new R-band photometry of two transits of TrES-1. With the help of all available transit times from literature this allows us to refine the estimate of the orbital period: P = (3.0300722 ± 0.0000002) d. Our observations will be useful for future investigations of timing variations caused by additional perturbing planets and/or stellar spots and/or moons.

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The Transit Light Curve Project. III. Tres Transits of TrES‐1

Cited by 106 publications

References 51 publications

THE 8 μm PHASE VARIATION OF THE HOT SATURN HD 149026b

THE 8 μm PHASE VARIATION OF THE HOT SATURN HD 149026b

Transit timing analysis of the exoplanets TrES-1 and TrES-2

Planetary transit observations at the University Observatory Jena: XO‐1b and TrES‐1

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