No variations in transit times for Qatar-1 b

Abstract

Aims. The transiting hot-Jupiter planet Qatar-1 b exhibits variations in transit times that could be perturbative. A hot Jupiter with a planetary companion on a nearby orbit would constitute an unprecedented planetary configuration, which is important for theories of the formation and evolution of planetary systems. We performed a photometric follow-up campaign to confirm or refute transit timing variations. Methods. We extend the baseline of transit observations by acquiring 18 new transit light curves acquired with 0.6−2.0 m telescopes. These photometric time series, together with data available in the literature, were analyzed in a homogenous way to derive reliable transit parameters and their uncertainties. Results. We show that the dataset of transit times is consistent with a linear ephemeris leaving no hint of any periodic variations with a range of 1 min. We find no compelling evidence of a close-in planetary companion to Qatar-1 b. This finding is in line with a paradigm that hot Jupiters are not components of compact multiplanetary systems. Based on dynamical simulations, we place tighter constraints on the mass of any fictitious nearby planet in the system. Furthermore, new transit light curves allowed us to redetermine system parameters with better precision than reported in previous studies. Our values generally agree with previous determinations.

Photometric investigation of hot exoplanets: TrES-3b and Qatar-1b

“…Binning was done to 70 points for each transit curve. Transit geometries are also plotted with the corresponding curves (see upper parts of the References Alsubai et al (2011) 0.1633 ± 0.0053 0.1454 ± 0.0015 83.47 ± 0.40 96.71 ± 1.11 von Essen et al (2013) 0.1558 ± 0.0024 0.1435 ± 0.0008 84.52 ± 0.24 - Covino et al (2013) 0.1601 ± 0.0025 0.1513 ± 0.0008 83.82 ± 0.25 97.63 ± 1.44 Mislis et al (2015) 0.1640 ± 0.0030 0.1475 ± 0.0009 84.03 ± 0.16 - Maciejewski et al (2015) 0.1582 ± 0.0017 0.1459 ± 0.0008 84.26 ± 0.17 98.50 ± 1.70 Collins et al (2015) 0.1600 ± 0.0018 0.1463 ± 0.0006 84.08 ± 0. As a measure of gravitational focusing, the Safronov number (Θ) given by Hansen and Barman (2007)…”

“…First TTV analysis presented by von Essen et al (2013) and they indicated a significant signal with a period of ∼ 190 days. However more recently, Maciejewski et al (2015) and Collins et al (2015) could not find evidence of an additional planet in the Qatar-1b system based on TTV analysis.…”

“…We used transit times for Qatar-1b was by combining our mid-transit times with data from von Essen et al (2013), Maciejewski et al (2015) and ETD. The improved linear ephemeris obtained is as follows:…”

Spitzer secondary eclipses of Qatar-1b

“…Mislis et al (2015) needed more precise data to detect the long-term TTVs found in von Es-sen et al (2013). Maciejewski et al (2015) concluded that the Qatar-1 system lacks any tertiary body able to produce periodic transit variations greater than 1 minute. Their analysis of the Qatar-1b orbital and planetary parameters do agree, however, with those of Covino et al (2013) and von Essen et al (2013).…”

Investigating Extra-solar Planetary System Qatar-1 through Transit Observations

“…So far, already more than 2653 extra-solar planetary systems have been found to transit their parent stars. In order to study the perturbation from small unknown planets and to constrain the overall orbital configuration in planetary systems, TTVs have been seriously investigated in recent years (Agol et al 2005;Holman et al 2005Holman et al , 2010Maciejewski et al 2015). Among the detected planetary systems, Qatar-1 attracts a lot of attention due to its strong transit signal and short orbital period.…”