We present a new observational campaign, DWARF, aimed at detection of circumbinary extrasolar planets using the timing www.an-journal.org

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All available mid-eclipse times of the eclipsing binary Z Draconis are analysed, and three sets of cyclic variations with periods of 20.1, 29.96 and 59.88 yr are found. The lowamplitude variations with the period of 20.1 yr may be attributed to the unavoidable and slight imperfection in the double-Keplerian model, which gives the periods of 29.96 and 59.88 yr. Interestingly, the Z Draconis system is close to a 2:1 mean-motion resonance, or 6:3:2 mean-motion resonance if the period of 20.1 yr is true. We also find that the best solutions tend to give the minimum eccentricities. Based on Kepler's third law, the outermost companion has the minimum mass of ∼ 0.77M , whereas the middle companion is an M dwarf star with a mass of ∼ 0.40M , suggesting that Z Draconis is a general N-body system.Subject headings: binaries: close -stars: individual: Z Draconis -methods: numerical.The oscillations in the mid-eclipse times of eclipsing binaries are usually interpreted as the lighttravel time (LTT) effect or the magnetic activity cycles (Applegate 1992;Yuan & Qian 2007). In the LTT model, a companion revolves around the eclipsing pair. The line-of-sight distance between the eclipsing pair and the barycentre of the whole system, d, varies with a strict period equal to the orbital period of the companion. After divided by the speed of light, c, we obtain the O − C value, d/c. Obviously, the multi-periodic variations in the eclipse times of an eclipsing binary provide us important constraints on the orbital characteristics of this multi-companion system, which usually comprises an eclipsing binary and multiple sub-stellar objects or planets. In the magnetic activity mechanism, the gravitational or magnetic force changes as the active component goes through a magnetic activity cycle, producing quasi-periodic variations in the eclipse times .Z Draconis (BD+73 • 533 = HIP 57348, V max = 10.67 mag) was first found to be an Algol-type binary (hereafter Z Dra AB) by Ceraski (1903). Due to its high declination and brightness, a large number of photometric data were obtained by small telescopes with alt-azimuthal mountings. The first radial velocity curve for the primary component was obtained by Struve (1947). Based

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We present the discovery of a highly irradiated and moderately inflated ultrahot Jupiter, TOI-1431b/MASCARA-5 b (HD 201033b), first detected by NASA’s Transiting Exoplanet Survey Satellite mission (TESS) and the Multi-site All-Sky Camera (MASCARA). The signal was established to be of planetary origin through radial velocity measurements obtained using SONG, SOPHIE, FIES, NRES, and EXPRES, which show a reflex motion of K = 294.1 ± 1.1 m s−1. A joint analysis of the TESS and ground-based photometry and radial velocity measurements reveals that TOI-1431b has a mass of M p = 3.12 ± 0.18 M J (990 ± 60 M ⊕), an inflated radius of R p = 1.49 ± 0.05 R J (16.7 ± 0.6 R ⊕), and an orbital period of P = 2.650237 ± 0.000003 days. Analysis of the spectral energy distribution of the host star reveals that the planet orbits a bright (V = 8.049 mag) and young ( 0.29 − 0.19 + 0.32 Gyr) Am type star with T eff = 7690 − 250 + 400 K, resulting in a highly irradiated planet with an incident flux of 〈 F 〉 = 7.24 − 0.64 + 0.68 × 109 erg s−1 cm−2 ( 5300 − 470 + 500 S ⊕ ) and an equilibrium temperature of T eq = 2370 ± 70 K. TESS photometry also reveals a secondary eclipse with a depth of 127 − 5 + 4 ppm as well as the full phase curve of the planet’s thermal emission in the red-optical. This has allowed us to measure the dayside and nightside temperature of its atmosphere as T day = 3004 ± 64 K and T night = 2583 ± 63 K, the second hottest measured nightside temperature. The planet’s low day/night temperature contrast (∼420 K) suggests very efficient heat transport between the dayside and nightside hemispheres. Given the host star brightness and estimated secondary eclipse depth of ∼1000 ppm in the K band, the secondary eclipse is potentially detectable at near-IR wavelengths with ground-based facilities, and the planet is ideal for intensive atmospheric characterization through transmission and emission spectroscopy from space missions such as the James Webb Space Telescope and the Atmospheric Remote-sensing Infrared Exoplanet Large-survey.