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J/AJ/154/4     Times of transits and occultations of WASP-12b     (Patra+, 2017)

The apparently decaying orbit of WASP-12b. Patra K.C., Winn J.N., Holman M.J., Yu L., Deming D., Dai F. <Astron. J., 154, 4-4 (2017)> =2017AJ....154....4P (SIMBAD/NED BibCode)
ADC_Keywords: Planets ; Stars, double and multiple Keywords: planetastar interactions - planets and satellites: individual WASP-12 b Abstract: We present new transit and occultation times for the hot Jupiter WASP-12b. The data are compatible with a constant period derivative: P.=-29±3ms/yr and P/P.=3.2Myr. However, it is difficult to tell whether we have observed orbital decay or a portion of a 14-year apsidal precession cycle. If interpreted as decay, the star's tidal quality parameter Qstar is about 2*105. If interpreted as precession, the planet's Love number is 0.44±0.10. Orbital decay appears to be the more parsimonious model: it is favored by Δχ2^_=5.5 despite having two fewer free parameters than the precession model. The decay model implies that WASP-12 was discovered within the final ∼0.2% of its existence, which is an unlikely coincidence but harmonizes with independent evidence that the planet is nearing disruption. Precession does not invoke any temporal coincidence, but it does require some mechanism to maintain an eccentricity of ~0.002 in the face of rapid tidal circularization. To distinguish unequivocally between decay and precession will probably require a few more years of monitoring. Particularly helpful will be occultation timing in 2019 and thereafter. Description: Between 2016 October and 2017 February, we observed seven transits of WASP-12 with the 1.2m telescope at the Fred Lawrence Whipple Observatory on Mt. Hopkins, Arizona. Images were obtained with the KeplerCam detector through a Sloan r'-band filter. The typical exposure time was 15s, chosen to give a signal-to-noise ratio of about 200 for WASP-12. The field of view of this camera is 23.1' on a side. We used 2*2 binning, giving a pixel scale of 0.68''. We measured two new occultation times based on hitherto unpublished Spitzer observations in 2013 December (program 90186, P.I. Todorov). Two different transits were observed, one at 3.6µm and one at 4.5µm. The data take the form of a time series of 32*32-pixel subarray images, with an exposure time of 2.0s per image. The data were acquired over a wide range of orbital phases, but for our purpose, we analyzed only the ∼14000 images within 4hr of each occultation. Objects: ----------------------------------------------------------------------- RA (ICRS) DE Designation(s) (Period) ----------------------------------------------------------------------- 06 30 32.79 +29 40 20.3 WASP-12 = TYC 1891-1178-1 (P=1.091420025) ----------------------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 79 113 Transit and occultation times
See also: J/A+A/588/L6 : WASP-12 transit light curves (Maciejewski+ 2016) J/ApJ/785/126 : HIRES radial velocity measurements (Knutson+, 2014) J/A+A/551/A108 : Multi-site obs. of WASP-12 b transit (Maciejewski+, 2013) J/ApJ/757/161 : Spectroscopy of 56 exoplanet host stars (Torres+, 2012) J/ApJ/757/18 : Radial velocities for hot Jupiter host stars (Albrecht+, 2012) J/ApJ/727/125 : Two secondary eclipses of WASP-12b with Spitzer (Campo+, 2011) J/AJ/141/179 : Transits of TrES-4b, HAT-P-3b and WASP-12b (Chan+, 2011) J/ApJ/720/872 : A spectropolarimetric analysis of WASP-12 (Fossati+, 2010) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 3 A3 --- Event Event (occ=occultation, tra=transit) 5- 17 F13.5 d BJD Barycentric Julian Date (BJD) of midtransit time (BJDTDB) 19- 25 F7.5 d e_BJD [0.0001/0.0022] Uncertainty in BJD 27- 31 I5 --- E [-1640/1370] Epoch number 33 A1 --- f_Ref [ab] Flag on Reference (a or b) (1) 35- 79 A45 --- Ref Reference
Note (1): Flag is defined as follows: a = Refers to the light curve obtained by Hebb et al. (2009ApJ...693.1920H) with the 2m Liverpool telescope, as analyzed by Maciejewski et al. 2013 (Cat. J/A+A/551/A108); b = Re-analyzed in this work.
History: From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 09-Aug-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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