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Post Info TOPIC: Qatar-1b
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Title: No variations in transit times for Qatar-1 b
Author: G. Maciejewski, M. Fernández, F. J. Aceituno, J. Ohlert, D. Puchalski, D. Dimitrov, M. Seeliger, M. Kitze, St. Raetz, R. Errman, H. Gilbert, A. Pannicke, J.-G. Schmidt, R. Neuhäuser

The transiting hot Jupiter planet Qatar-1 b was presented to exhibit variations in transit times that could be of perturbative nature. A hot Jupiter with a planetary companion on a nearby orbit would constitute an unprecedented planetary configuration, important for theories of formation and evolution of planetary systems. We performed a photometric follow-up campaign to confirm or refute transit timing variations. 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 analysed in a homogenous way to derive reliable transit parameters and their uncertainties. We show that the dataset of transit times is consistent with a linear ephemeris leaving no hint for any periodic variations with a range of 1 min. We find no compelling evidence for the existence 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 multi-planetary systems. Based on dynamical simulations, we place tighter constraints on a mass of any fictitious nearby planet in the system. Furthermore, new transit light curves allowed us to redetermine system parameters with the precision better than that reported in previous studies. Our values generally agree with previous determinations.

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Blobrana


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Title: Qatar-1: indications for possible transit timing variations
Authors: C. von Essen, S. Schröter, E. Agol, J.H.M.M. Schmitt

Variations in the timing of transiting exoplanets provide a powerful tool detecting additional planets in the system. Thus, the aim of this paper is to discuss the plausibility of transit timing variations on the Qatar-1 system by means of primary transit light curves analysis. Furthermore, we provide an interpretation of the timing variation. We observed Qatar-1 between March 2011 and October 2012 using the 1.2 m OLT telescope in Germany and the 0.6 m PTST telescope in Spain. We present 26 primary transits of the hot Jupiter Qatar-1b. In total, our light curves cover a baseline of 18 months. We report on indications for possible long-term transit timing variations (TTVs). Assuming that these TTVs are true, we present two different scenarios that could explain them. Our reported ~190 days TTV signal can be reproduced by either a weak perturber in resonance with Qatar-1b, or by a massive body in the brown dwarf regime. More observations and radial velocity monitoring are required to better constrain the perturber's characteristics. We also refine the ephemeris of Qatar-1b, which we find to be T_0 = 2456157.42204 ± 0.0001 BJD_tdb , and P = 1.4200246 ± 0.0000007 days, and improve the system orbital parameters.

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Blobrana


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Title: Qatar-1b: a hot Jupiter orbiting a metal-rich K dwarf star
Authors: K.A.Alsubai, N.R.Parley, D.M.Bramich, R.G.West, P.M.Sorensen, A.Collier Cameron, D.W.Latham, K.Horne, D.R.Anderson, D.J.A.Brown, L.A.Buchhave, G.A.Esquerdo, M.E.Everett, G. Fürész, C.Hellier, G.M.Miller, D.Pollacco, S.N.Quinn, J.C.Smith, R.P.Stefanik, A.Szentgyorgyi

We report the discovery and initial characterisation of Qatar-1b, a hot Jupiter orbiting a metal-rich K dwarf star, the first planet discovered by the Alsubai Project exoplanet transit survey. We describe the strategy used to select candidate transiting planets from photometry generated by the Alsubai Project instrument. We examine the rate of astrophysical and other false positives found during the spectroscopic reconnaissance of the initial batch of candidates. A simultaneous fit to the follow-up radial velocities and photometry of Qatar-1b yield a planetary mass of 1.09±0.08 Mjup and a radius of 1.16±0.05 Rjup. The orbital period and separation are 1.420033 days and 0.0234 AU for an orbit assumed to be circular. The stellar density, effective temperature and rotation rate indicate an age greater than 4 Gyr for the system.

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Students from St Andrews University have helped to discover a new gas giant using planet-hunting cameras which could ultimately lead astronomers to new Earths.
PhD students Grant Miller and David Brown used Scotland's largest optical telescope to confirm the presence of Qatar-1b - a gas planet similar to Jupiter.
They used the 0.9m diameter James Gregory telescope at the university campus observatory, to measure its diameter.
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Blobrana


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In an exciting example of international collaboration, a Qatar astronomer teamed with scientists at the Harvard-Smithsonian Center for Astrophysics (CfA) and other institutions to discover a new alien world. This "hot Jupiter," now named Qatar-1b, adds to the growing list of alien planets orbiting distant stars. Its discovery demonstrates the power of science to cross political boundaries and increase ties between nations.
The resulting data confirmed the existence of a planet now called Qatar-1b, orbiting an orange Type K star 550 light-years away. Qatar-1b is a gas giant 20 percent larger than Jupiter in diameter and 10 percent more massive. It belongs to the "hot Jupiter" family because it orbits 2.2 million miles from its star - only six stellar radii away. The planet roasts at a temperature of around 2,000 degrees Fahrenheit.
Qatar-1b circles its star once every 1.4 days, meaning that its "year" is just 34 hours long. It's expected to be tidally locked with the star, so one side of the planet always faces the star. As a result, the planet spins on its axis once every 34 hours - three times slower than Jupiter, which rotates once in 10 hours.
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Blobrana


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Students at St Andrews University have helped discover a new planet bigger than Jupiter.

PhD students Grant Miller and David Brown used Scotland's largest optical telescope, the 0.9m diameter James Gregory telescope at the campus observatory, to confirm the presence and measure the diameter of the new planet, contributing to the discovery of a new alien world.
The St Andrews team helped to find the new planet in record time thanks to teamwork and internet communications between astronomers in Qatar, the US, Germany, Denmark, and at the Universities of Leicester and Keele.
The planet, described as a 'hot Jupiter' which has been named Qatar-1b, adds to the growing list of alien planets orbiting distant stars discovered by scientists around the world.
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