TASTE II. A new observational study of transit time variations in HAT-P-13b^⋆,⋆⋆

¹ Dipartimento di AstronomiaUniversità degli Studi di Padova, Vicolo dell’Osservatorio 3, 35122 Padova, Italy
e-mail: valerio.nascimbeni@unipd.it; giampaolo.piotto@unipd.it
² Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
e-mail: bedin@stsci.edu
³ Astronomical Observatory of the Autonomous Region of the Aosta Valley, Loc. Lignan 39, 11020 Nus (AO), Italy
⁴ INAF – Osservatorio Astronomico di Padova, vicolo dell’Osservatorio 5, 35122 Padova, Italy

Received: 4 March 2011
Accepted: 22 May 2011

Abstract

TASTE (The Asiago Search for Transit timing variations of Exoplanets) project is collecting high-precision, short-cadence light curves for a selected sample of transiting exoplanets. It has been claimed that the hot jupiter HAT-P-13b suddenly deviated from a linear ephemeris by  ~20 min, implying that there is a perturber in the system. Using five new transits, we discuss the plausibility of this transit time variation (TTV), and show that a periodic signal should not be excluded. More follow-up observations are required to constrain the mass and the orbit of the hypothetical perturber.