Homogeneously derived transit timings for 17 exoplanets and reassessed TTV trends for WASP-12 and WASP-4

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Baluev R., Sokov E. N., Jones H. R. A., Shaidulin V. S., Sokova I. A., Nielsen L. D., ...More

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol.490, no.1, pp.1294-1312, 2019 (SCI-Expanded, Scopus) identifier

  • Publication Type: Article / Article
  • Volume: 490 Issue: 1
  • Publication Date: 2019
  • Doi Number: 10.1093/mnras/stz2620
  • Journal Name: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1294-1312
  • Keywords: methods: data analysis, methods: statistical, techniques: photometric, techniques: radial velocities, surveys, planetary systems, HIGH-PRECISION PHOTOMETRY, LIMB-DARKENING COEFFICIENTS, STELLAR ATMOSPHERE MODELS, LIGHT-CURVE PROJECT, PLANETARY SYSTEM, RADIAL-VELOCITY, HOT JUPITER, TRANSMISSION SPECTRUM, PHYSICAL-PROPERTIES, IMPROVED PARAMETERS
  • Open Archive Collection: AVESIS Open Access Collection
  • Ankara University Affiliated: Yes

Abstract

We homogeneously analyse similar to 3.2 x 10(5) photometric measurements for similar to 1100 transit light curves belonging to 17 exoplanet hosts. The photometric data cover 16 years (2004-2019) and include amateur and professional observations. Old archival light curves were reprocessed using up-to-date exoplanetary parameters and empirically debiased limb-darkening models. We also derive self-consistent transit and radial-velocity fits for 13 targets. We confirm the non-linear transit timing variation (TTV) trend in the WASP-12 data at a high significance, and with a consistent magnitude. However, Doppler data reveal hints of a radial acceleration of about -7.5 +/- 2.2 ms(-1) yr(-1), indicating the presence of unseen distant companions, and suggesting that roughly 10 per cent of the observed TTV was induced via the light-travel (or Roemer) effect. For WASP-4, a similar TTV trend suspected after the recent TESS observations appears controversial and model dependent. It is not supported by our homogeneous TTV sample, including 10 ground-based EXPANSION light curves obtained in 2018 simultaneously with TESS. Even if the TTV trend itself does exist in WASP-4, its magnitude and tidal nature are uncertain. Doppler data cannot entirely rule out the Roemer effect induced by possible distant companions.