http://www.home.umk.pl/~gmac/TTV/ 2026-06-28T03:05:00+02:00 http://www.home.umk.pl/~gmac/TTV/ http://www.home.umk.pl/~gmac/TTV/lib/tpl/doogiestpl/images/favicon.ico text/html 2018-09-24T15:12:30+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=backups&rev=1537794750&do=diff Back-up targets As a result of our project, a number of transit light curves has been observed for back-up targets. Such data can be used to refine transit ephemerides (e.g. Maciejewski et al. 2013, IBVS 6082) or to redetermine system parameters (e.g. Maciejewski et al. 2011, Acta Astron. 61, 25). Below there is a list of planets that have been observed only once. Any new complete or partial transit light curves are very welcome. Light curve collected so far are listed in parentheses. text/html 2020-05-08T16:41:53+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=download&rev=1588948913&do=diff RESULTS & DATA REFEREED PAPERS * Planet-star interactions with precise transit timing. II. The radial-velocity tides and a tighter constraint on the orbital decay rate in the WASP-18 system G.Maciejewski, H.A.Knutson, A.W.Howard, H.Isaacson, E.Fernández-Lajús, R.P.DiSisto, C.Migaszewski text/html 2017-06-07T09:45:29+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=hat4&rev=1496821529&do=diff HAT-P-4 b AIMS The transiting exoplanet HAT-P-4 b orbits a slightly evolved late F-type star every 3.07 d (Kovacs et al. 2007). It has a mass of 0.68 M_Jup and bloated radius of 1.27 R_Jup. These parameters make the planet challenging for models of the physical structure of hot Jupiters. Precise radial velocities show a long-term trend which could be caused by an additional body on a wide orbit, having a mass not smaller than 1.5 M_Jup (Knutson et al. 2014). The transit duration is about 4 hou… text/html 2017-02-21T10:23:38+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=hat15&rev=1487669018&do=diff HAT-P-15 b AIMS HAT-P-15, a G5 dwarf star, was found to harbor a planetary companion by Kovács et al. (2010). Although the circularization timescale is in the order of the age of the star and therefore the eccentricity of 0.190 is not directly indicating a perturber in the system, HAT-P-15 nevertheless is an interesting case to study TTVs of planet transiting a solar-type star. text/html 2017-02-21T10:23:38+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=hat18&rev=1487669018&do=diff HAT-P-18 b AIMS HAT-P-18b, discovered by Hartman et al. (2011), is a 0.197 jupiter mass planet with a radius of 0.995 jupiter radii surrounding a K2 dwarf star. Though the obtained RV signals show no significant deviations from the Keplerian fit, the lightcurves of the two availlable transits show some clear variations in the transit shape worth analyzing with further transit observations. text/html 2017-02-21T10:23:38+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=hat19&rev=1487669018&do=diff HAT-P-19 b AIMS The K1 dwarf HAT-P-19 was found to show transits by Hartman et al. (2011). Together with RV analysis they could show that it is surrounded by a 0.292 jupiter mass planet with a radius of 1.132 jupiter radii. The RV residuals from a Keplerian fit were found to show a linear trend which indicates the existence of a third body in the system. Even though the eccentricity is quite small (e=0.067+/-0.042) compared to other TTV-targets, analysing transit timing variations can be used … text/html 2017-02-21T10:23:38+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=hat23&rev=1487669018&do=diff HAT-P-23 b AIMS The HAT-P-23 system consists of a G0 dwarf star and a 2 Jupiter-mass planet on a 1.2 d orbit. The orbital eccentricity of about 0.1 was reported. Our analysis of mid-transit times collected so far indicates that a linear ephemeris does not reproduce observations. A long-term trend is visible in the transit time residuals that could be a sign of orbital period shortening (and orbital decay). This could also be a fragment of periodic variation caused by apsidal precession. Numeri… text/html 2017-02-21T10:23:38+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=hat27&rev=1487669018&do=diff HAT-P-27 b / WASP-40 b AIMS HAT-P-27 b (discovered by Béky et al. 2011), also known as WASP-40 b (individually discovered by Anderson et al. (2011)). Looking at the RV-meassurements of both groups, one can see an almost perfect fit of the Béky et al. data, but strong deviations in the Anderson et al. data. Interestingly both groups come to equal results leading to a 0.62 jupiter mass planet with a radius of 1.05 jupiter radii. While Anderson et al. have adopted an eccentricity of 0, Béky et al… text/html 2017-06-07T12:09:29+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=migration&rev=1496830169&do=diff Migration history AIMS It is commonly believed that giant planets are formed beyond the water-ice line in the protoplanetary disc, where there is a lot of solid material rich in ice condensation. Then, planets migrate towards their host stars to orbits observed today. Theoretical studies usually indicate on two main scenarios of migration: disc-driven migration and high-eccentricity migration. The former would yield mainly circular orbits (or orbits with moderate eccentricities) due to interac… text/html 2017-02-21T10:23:38+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=project&rev=1487669018&do=diff STRATEGY Timing of transiting exoplanets is expected to provide discoveries of additional, even very low mass bodies in extrasolar systems. In a single-planet system, a transiting planet orbits its host star on a Keplerian orbit. If there is another planet in the system, it interacts gravitationally with the transiting planet what generates deviations from the strictly Keplerian case. These perturbations result in a quasi-periodic signal in an observed-minus-calculated (O-C) diagram of the tran… text/html 2017-02-21T10:23:38+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=qatar1&rev=1487669018&do=diff Qatar-1 b AIMS Qatar-1 b is a typical hot Jupiter with a mass of 1.09 M_Jup and a radius of 1.16 R_Jup (Alsubai et al. 2011). The planet orbits its host star within 1.4 d on a circular orbit. The radial velocity observations throughout a transit show a signature of the Rositter-McLaughlin effect, consistent with a sky-projected obliquity close to zero (Covino et al. 2013). text/html 2017-06-07T10:50:28+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=starplanet&rev=1496825428&do=diff Star-planet interactions AIMS Planets on short-period orbits are expected to be unstable to tidal dissipation and finally spiral in toward the host star because they transfer the angular momentum of the orbital motion through tidal dissipation inside the star (e.g., Levrard et al. 2009; Essick & Weinberg 2016). The rate of this orbital decay can help determine the efficiency of the tide dissipation. The decaying orbital period is expected to be observed through transit timing. For some planets… text/html 2017-02-21T10:23:38+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=start&rev=1487669018&do=diff ABOUT THE PROJECT In 2009 we launched international observing campaigns which are dedicated to detecting and characterising signals of transit timing variation for carefully selected transiting exoplanets. We base on collaboration within the framework of the text/html 2017-02-21T10:23:38+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=wasp14&rev=1487669018&do=diff WASP-14 b AIMS The star WASP-14 was found to have a transiting planetary-mass companion by Joshi et al. (2009). The planet orbits the host star with a period of 2.244 day causing transits with the depth of 11 mmag and a duration of 2.8 hours. A very interesting features of WASP-14b reported by Joshi et al. (2009) is its high orbital eccentricity (e = 0.091 +/- 0.003) for its small orbital distance of 0.036 AU. The high eccentricity of WASP-14b may indicate either a system age comparable to the… text/html 2017-02-21T10:23:38+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=wasp21&rev=1487669018&do=diff WASP-21 b AIMS WASP-21b was found by Bouchy et al. (2010). Its host star is a G3 main sequence star. Planetary parameters of a radius of 1.07 jupiter radii and a mass of 0.3 jupiter masses were derived. Though the eccentricity was derived to be very small and therefore fixed to zero in the models, the radial velocity analysis shows some interesting deviations from the fit. text/html 2017-02-21T10:23:38+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=wasp38&rev=1487669018&do=diff WASP-38 b AIMS WASP-38b is a recently by Barros et al. (2010) discovered planet around a F8 main sequence star showing a nonzero eccentricity. Radial velocity follow-up observations show that there are some points that cannot be explained by a strictly Keplerian orbit, making WASP-38 an interesting case to look for variations. text/html 2017-02-21T10:23:38+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=wasp84&rev=1487669018&do=diff WASP-84 b AIMS In the discovery paper by Anderson et al. (2015), it is suggested that the warm Jupiter-like planet WASP-84 b is likely to have migrated via interaction with the protoplanetary disk. Other planets, which were formed in the system, could survive on close-in orbits with architectures similar to that of the compact WASP-47 system. They could induce variations in transit times of WASP-84 b. We want to check whether there is any TTV signal or not. text/html 2017-02-21T10:23:38+02:00 http://www.home.umk.pl/~gmac/TTV/doku.php?id=wasp106&rev=1487669018&do=diff WASP-106 b AIMS The exoplanet WASP-106 b belongs to a small group of transiting Jupiter-like planets on a relatively wide orbits discovered from the ground (Smith et al. 2014). This warm Jupiter has a mass of 2 M_Jup and needs over 9 days to orbit its host star. A long orbital period, long duration of a transit event of 5 hours, and transit depth of only 8 mmag make follow-up observations challenging from the ground. Few complete transits are observable each year from a given site. The literat…