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DW Cnc is an intermediate polar which has previously been observed in both high and low states. Observations of the high state of DW Cnc have previously revealed a spin period at ∼38.6 min, however, observations from the 2018 to 2019 low state showed no evidence of the spin period. We present results from our analysis of 12 s cadence photometric data collected by Next Generation Transit Survey of DW Cnc during the high state which began in 2019. Following the previously reported suppression of the spin period signal, we identify the return of this signal during the high state, consistent with previous observations of it. We identify this as the restarting of accretion during the high state. We further identified three short outbursts lasting ∼1 d in DW Cnc with a mean recurrence time of ∼60 d and an amplitude of ∼1 mag. These are the first outbursts identified in DW Cnc since 2008. Due to the short nature of these events, we identify them not as a result of accretion instabilities but instead either from instabilities originating from the interaction of the magnetorotational instability in the accretion disc and the magnetic field generated by the white dwarf or the result of magnetic gating. [ABSTRACT FROM AUTHOR]

We present the discovery of two new hot Jupiters identified from the Wide-Angle Search for Planets (WASP) survey, WASP-186b and WASP-187b (TOI-1494.01 and TOI-1493.01). Their planetary nature was established from SOPHIE spectroscopic observations, and additional photometry was obtained from Transiting Exoplanet Survey Satellite. Stellar parameters for the host stars are derived from spectral line, infrared flux method, and isochrone placement analyses. These parameters are combined with the photometric and radial velocity data in a Markov chain Monte Carlo method to determine the planetary properties. WASP-186b is a massive Jupiter (4.22 ± 0.18  M J, 1.11 ± 0.03  R J) orbiting a mid-F star on a 5.03-d eccentric (e = 0.327 ± 0.008) orbit. WASP-187b is a low-density (0.80 ± 0.09  M J, 1.64 ± 0.05  R J) planet in a 5.15-d circular orbit around a slightly evolved early F-type star. [ABSTRACT FROM AUTHOR]

We report the discovery of eight hot-Jupiter exoplanets from the WASP-South transit survey. WASP-144b has a mass of 0.44 M Jup, a radius of 0.85 R Jup, and is in a 2.27-d orbit around a V  = 12.9, K2 star which shows a 21-d rotational modulation. WASP-145Ab is a 0.89 M Jup planet in a 1.77-d orbit with a grazing transit. The host is a V  = 11.5, K2 star with a companion 5 arcsec away and 1.4 mag fainter. WASP-158b is a relatively massive planet at 2.8 M Jup with a radius of 1.1 R Jup and a 3.66-d orbit. It transits a V  = 12.1, F6 star. WASP-159b is a bloated hot Jupiter (1.4 R Jup and 0.55 M Jup) in a 3.8-d orbit around a V  = 12.9, F9 star. WASP-162b is a massive planet in a relatively long and highly eccentric orbit (5.2 M Jup, P  = 9.6 d, e  = 0.43). It transits a V  = 12.2, K0 star. WASP-168b is a bloated hot Jupiter (0.42 M Jup; 1.5 R Jup) in a 4.15-d orbit with a grazing transit. The host is a V  = 12.1, F9 star. WASP-172b is a bloated hot Jupiter (0.5 M Jup; 1.6 R Jup) in a 5.48-d orbit around a V  = 11.0, F1 star. WASP-173Ab is a massive planet (3.7 M Jup) with a 1.2 R Jup radius in a circular orbit with a period of 1.39 d. The host is a V  = 11.3, G3 star, being the brighter component of the double-star system WDS23366 − 3437, with a companion 6 arcsec away and 0.8 mag fainter. One of the two stars shows a rotational modulation of 7.9 d. [ABSTRACT FROM AUTHOR]

We describe seven exoplanets transiting stars of brightness V = 10.1-12.4. WASP-130b is a 'warm Jupiter' having an orbital period of 11.6 d around a metal-rich G6 star. Its mass and radius (1.23 ± 0.04 MJup and 0.89 ± 0.03 RJup) support the trend that warm Jupiters have smaller radii than hot Jupiters. WASP-131b is a bloated Saturn-mass planet (0.27 MJup and 1.22 RJup). Its large scaleheight and bright (V = 10.1) host star make it a good target for atmospheric characterization. WASP-132b (0.41 MJup and 0.87 RJup) is among the least irradiated and coolest of WASP planets, having a 7.1-d orbit around a K4 star. WASP-139b is a 'super-Neptune' akin to HATS-7b and HATS-8b, being the lowest mass planet yet found by WASP (0.12 MJup and 0.80 RJup). The metal-rich K0 host star appears to be anomalously dense, akin to HAT-P-11.WASP-140b is a 2.4-MJup planet in an eccentric (e = 0.047 ± 0.004) 2.2-d orbit. The planet's radius is large (1.4 RJup), but uncertain owing to the grazing transit (b = 0.93). The 10.4-d rotation period of the K0 host star suggests a young age, and the time-scale for tidal circularization is likely to be the lowest of all known eccentric hot Jupiters. WASP-141b (2.7MJup, 1.2RJup and P = 3.3 d) and WASP-142b (0.84MJup, 1.53 RJup and P = 2.1 d) are typical hot Jupiters orbiting metal-rich F stars. We show that the period distribution within the hot-Jupiter bulge does not depend on the metallicity of the host star. [ABSTRACT FROM AUTHOR]

We present the results of a study of a large sample of A and Am stars with spectral types from Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and light curves from Wide Area Search for Planets (WASP). We find that, unlike normal A stars, δ Sct pulsations in Am stars are mostly confined to the effective temperature range 6900 < Teff < 7600 K.We find evidence that the incidence of pulsations inAmstars decreases with increasingmetallicism (degree of chemical peculiarity). The maximum amplitude of the pulsations in Am stars does not appear to vary significantly with metallicism. The amplitude distributions of the principal pulsation frequencies for both A and Am stars appear very similar and agree with results obtained from Kepler photometry. We present evidence that suggests turbulent pressure is the main driving mechanism in pulsating Am stars, rather than the κ-mechanism, which is expected to be suppressed by gravitational settling in these stars. [ABSTRACT FROM AUTHOR]

We have analysed around 170 000 individual photometric WASP (Wide Angle Search for Planets) measurements of 15 well-established λ Bootis stars to search for variability. The λ Bootis stars are a small group of late-B to early-F, Pop I, stars that show moderate to extreme (surface) underabundances (up to a factor 100) of most Fe-peak elements, but solar abundances of lighter elements (C, N,Oand S). They are excellent laboratories for the study of fundamental astrophysical processes such as diffusion, meridional circulation, stellar winds and accretion in the presence of pulsation. From the 15 targets, 8 are variable and 7 are apparently constant with upper limits between 0.8 and 3.0 mmag. We present a detailed time-series analysis and a comparison with previously published results. From an asteroseismologic study, we conclude that the found chemical peculiarities are most probably restricted to the surface. [ABSTRACT FROM AUTHOR]

We present new warm Spitzer occultation photometry of WASP-26 at 3.6 and 4.5 μm along with new transit photometry taken in the g, r and i bands. We report the first detection of the occultation of WASP-26b, with occultation depths at 3.6 and 4.5 μm of 0.001 26 ± 0.000 13 and 0.001 49 ± 0.000 16 corresponding to brightness temperatures of 1825 ± 80 and 1725 ± 89 K, respectively. We find that the eccentricity of the orbit is consistent with a circular orbit at the 1σ level ($e=0.0028 ^{+ 0.0097}_{- 0.0022}$, 3σ upper limit e < 0.04). According to the activity–inversion relation of Knutson et al., WASP-26b is predicted to host a thermal inversion. The brightness temperatures deduced from the eclipse depths are consistent with an isothermal atmosphere, although the planet may host a weak thermal inversion given the uncertainties on these values. The data are equally well fitted by atmospheric models with or without a thermal inversion. We find that variation in activity of solar-like stars does not change enough over the time-scales of months or years to change the interpretation of the Knutson et al. activity–inversion relation, provided that the measured activity level is averaged over several nights. Further data are required to fully constrain the thermal structure of the atmosphere because the planet lies very close to the boundary between atmospheres with and without a thermal inversion. [ABSTRACT FROM AUTHOR]

We report detection of thermal emission from the exoplanet WASP-19b at 3.6, 4.5, 5.8 and 8.0 µm. We used the InfraRed Array Camera on the Spitzer Space Telescope to observe two occultations of WASP-19b by its host star. We combine our new detections with previous measurements of WASP-19b's emission at 1.6 and 2.09 µm to construct a spectral energy distribution of the planet's dayside atmosphere. By comparing this with model-atmosphere spectra, we find that the dayside atmosphere of WASP-19b lacks a strong temperature inversion. As WASP-19 is an active star (log R'HK =-4.50 ± 0.03), this finding supports the hypothesis of Knutson, Howard and Isaacson that inversions are suppressed in hot Jupiters orbiting active stars. The available data are unable to differentiate between a carbon-rich and an oxygen-rich atmosphere. [ABSTRACT FROM AUTHOR]

We have made a detailed spectral analysis of 11 Wide Angle Search for Planets (WASP) planet host stars using high signal-to-noise ratio (S/N) HARPS spectra. Our line list was carefully selected from the spectra of the Sun and Procyon, and we made a critical evaluation of the atomic data. The spectral lines were measured using equivalent widths. The procedures were tested on the Sun and Procyon prior to be being used on the WASP stars. The effective temperature (Teff), surface gravity (log g), microturbulent velocity (vmic) and metallicity were determined for all the stars. We show that abundances derived from high S/N spectra are likely to be higher than those obtained from low S/N spectra, as noise can cause the equivalent width to be underestimated. We also show that there is a limit to the accuracy of stellar parameters that can be achieved, despite using high S/N spectra, and the average uncertainty in Teff, log g, vmic and metallicity is 83 K, 0.11 dex, 0.11 km s−1 and 0.10 dex, respectively. [ABSTRACT FROM AUTHOR]

ABSTRACT We present seven new transiting hot Jupiters from the WASP-South survey. The planets are all typical hot Jupiters orbiting stars from F4 to K0 with magnitudes of V = 10.3-12.5. The orbital periods are all in the range of 3.9-4.6 d, the planetary masses range from 0.4 to 2.3 MJup and the radii from 1.1 to 1.4 RJup. In line with known hot Jupiters, the planetary densities range from Jupiter-like to inflated (ρ = 0.13-1.07ρJup). We use the increasing numbers of known hot Jupiters to investigate the distribution of their orbital periods and the 3-4 d 'pile-up'. [ABSTRACT FROM AUTHOR]

ABSTRACT We report the discovery of three extrasolar planets that transit their moderately bright ( mV= 12-13) host stars. WASP-44b is a 0.89- MJup planet in a 2.42-day orbit around a G8V star. WASP-45b is a 1.03- MJup planet which passes in front of the limb of its K2V host star every 3.13 days. Weak Ca ii H&K emission seen in the spectra of WASP-45 suggests that the star is chromospherically active. WASP-46b is a 2.10- MJup planet in a 1.43-day orbit around a G6V star. Rotational modulation of the light curves of WASP-46 and weak Ca ii H&K emission in its spectra show the star to be photospherically and chromospherically active. We imposed circular orbits in our analyses as the radial-velocity data are consistent with (near-)circular orbits, as could be expected from both empirical and tidal-theory perspectives for such short-period, ∼Jupiter-mass planets. We discuss the impact of fitting for eccentric orbits for such planets when not supported by the data. The derived planetary and stellar radii depend on the fitted eccentricity and these parameters inform intense theoretical efforts concerning tidal circularization and heating, bulk planetary composition and the observed systematic errors in planetary and stellar radii. As such, we recommend exercising caution in fitting the orbits of short-period, ∼Jupiter-mass planets with an eccentric model when there is no evidence of non-circularity. [ABSTRACT FROM AUTHOR]

ABSTRACT We present the results of trawling through the SuperWASP data base for classical and recurrent novae. We report light curves for a nova in eruption, and for classical novae and a recurrent nova in quiescence. For five objects in quiescence, we report periodicity, arising in most cases from orbital modulation of the light from the cool secondary star. The stability of the SuperWASP system means that these data have huge potential for the study not only of novae in eruption, but also of the long-term modulations of light during quiescence. [ABSTRACT FROM AUTHOR]

ABSTRACT We have identified a star in the Wide Angle Search for Planets (WASP) archive photometry with an unusual light curve due to the total eclipse of a small, hot star by an apparently normal A-type star and with an orbital period of only 0.668 d. From an analysis of the WASP light curve together with V-band and IC-band photometry of the eclipse and a spectroscopic orbit for the A-type star we estimate that the companion star has a mass of 0.23 ± 0.03 M⊙ and a radius of 0.33 ± 0.01 R⊙, assuming that the A-type star is a main-sequence star with the metallicity appropriate for a thick-disc star. The effective temperature of the companion is 13 400 ± 1200 K from which we infer a luminosity of 3 ± 1 L⊙. From a comparison of these parameters to various models we conclude that the companion is most likely to be the remnant of a red giant star that has been very recently stripped of its outer layers by mass transfer on to the A-type star. In this scenario, the companion is currently in a shell hydrogen-burning phase of its evolution, evolving at nearly constant luminosity to hotter effective temperatures prior to ceasing hydrogen burning and fading to become a low-mass white dwarf composed of helium (He-WD). The system will then resemble the pre-He-WD/He-WD companions to A- and B-type stars recently identified from their Kepler satellite light curves (KOI-74, KOI-81 and KIC 10657664). This newly discovered binary offers the opportunity to study the evolution of a stripped red giant star through the pre-He-WD stage in great detail. [ABSTRACT FROM AUTHOR]

ABSTRACT We report the discovery and initial characterization of Qatar-1b, a hot Jupiter-orbiting metal-rich K dwarf star, the first planet discovered by the Qatar Exoplanet Survey. We describe the strategy used to select candidate transiting planets from photometry generated by the Qatar Exoplanet Survey camera array. 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 yields a planetary mass of 1.09 ± 0.08 MJ and a radius of 1.16 ± 0.05 RJ. The orbital period and separation are 1.420 033 ± 0.000 016 d and 0.023 43 ± 0.000 26 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. [ABSTRACT FROM AUTHOR]

BSTRACT [ABSTRACT FROM AUTHOR]

We present the results of photometric surveys for stellar rotation in the Hyades and in Praesepe, using data obtained as part of the SuperWASP exoplanetary transit-search programme. We determined accurate rotation periods for more than 120 sources whose cluster membership was confirmed by common proper motion and colour-magnitude fits to the clusters' isochrones. This allowed us to determine the effect of magnetic braking on a wide range of spectral types for expected ages of 600 Myr for the Hyades and Praesepe. Both clusters show a tight and nearly linear relation between colour and rotation period in the F, G and K spectral range. This confirms that loss of angular momentum was significant enough that stars with strongly different initial rotation rates have converged to the same rotation period for a given mass, by the ages of Hyades and Praesepe. In the case of the Hyades, our colour-period sequence extends well into the M dwarf regime and shows a steep increase in the scatter of the colour-period relation, with identification of numerous rapid rotators from 0.5 M down to the lowest masses probed by our survey (0.25 M). This provides crucial constraints on the rotational braking time-scales and further clears the way to use gyrochronology as an accurate age measurement tool for main-sequence stars. [ABSTRACT FROM AUTHOR]

ABSTRACT We report the detection of a 0.6 MJ extrasolar planet by WASP-South, WASP-25b, transiting its solar-type host star every 3.76 d. A simultaneous analysis of the WASP, FTS and Euler photometry and CORALIE spectroscopy yields a planet of Rp= 1.22 RJ and Mp= 0.58 MJ around a slightly metal-poor solar-type host star, [Fe/H]=− 0.05 ± 0.10, of R*= 0.92 R⊙ and M*= 1.00 M⊙. WASP-25b is found to have a density of ρp= 0.32 ρJ, a low value for a sub-Jupiter mass planet. We investigate the relationship of planetary radius to planetary equilibrium temperature and host star metallicity for transiting exoplanets with a similar mass to WASP-25b, finding that these two parameters explain the radii of most low-mass planets well. [ABSTRACT FROM AUTHOR]

ABSTRACT We have performed extensive simulations to explore the possibility of detecting eclipses and transits of close, substellar and planetary companions to white dwarfs in WASP (the UK Wide-Angle Search for Planets) light curves. Our simulations cover companions ∼0.3 < Rpl < 12 R and orbital periods 2 < P < 15 d, equivalent to orbital radii 0.003 < a < 0.1 au. For Gaussian random noise, WASP is sensitive to transits by companions as small as the Moon orbiting a V≃ 12 white dwarf. For fainter white dwarfs, WASP is sensitive to increasingly larger radius bodies. However, in the presence of correlated noise structure in the light curves, the sensitivity drops, although Earth-sized companions remain detectable, in principle, even in low signal-to-noise data. Mars-sized, and even Mercury-sized, bodies yield reasonable detection rates in high-quality light curves with little residual noise. We searched for eclipses and transit signals in long-term light curves of a sample of 194 white dwarfs resulting from a cross-correlation of the McCook & Sion catalogue and the WASP archive. No evidence for eclipsing or transiting substellar and planetary companions was found. We used this non-detection and results from our simulations to place tentative upper limits to the frequency of such objects in close orbits at white dwarfs. While only weak limits can be placed on the likely frequency of Earth-sized or smaller companions, brown dwarfs and gas giants (radius ≈ Rjup) with periods <0.1-0.2 d must certainly be rare (<10 per cent). More stringent constraints likely require significantly larger white dwarf samples, higher observing cadence and continuous coverage. The short duration of eclipses and transits of white dwarfs compared to the cadence of WASP observations appears to be one of the main factors limiting the detection rate in a survey optimized for planetary transits of main-sequence stars. [ABSTRACT FROM AUTHOR]

Most of our knowledge of extrasolar planets rests on precise radial-velocity measurements, either for direct detection or for confirmation of the planetary origin of photometric transit signals. This has limited our exploration of the parameter space of exoplanet hosts to solar- and later-type, sharp-lined stars. Here we extend the realm of stars with known planetary companions to include hot, fast-rotating stars. Planet-like transits have previously been reported in the light curve obtained by the SuperWASP survey of the A5 star HD 15082 (WASP–33; ). Here we report further photometry and time-series spectroscopy through three separate transits, which we use to confirm the existence of a gas-giant planet with an orbital period of 1.22 d in orbit around HD 15082. From the photometry and the properties of the planet signal travelling through the spectral line profiles during the transit, we directly derive the size of the planet, the inclination and obliquity of its orbital plane and its retrograde orbital motion relative to the spin of the star. This kind of analysis opens the way to studying the formation of planets around a whole new class of young, early-type stars, hence under different physical conditions and generally in an earlier stage of formation than in sharp-lined late-type stars. The reflex orbital motion of the star caused by the transiting planet is small, yielding an upper mass limit of 4.1 MJupiter on the planet. We also find evidence of a third body of substellar mass in the system, which may explain the unusual orbit of the transiting planet. In HD 15082, the stellar line profiles also show evidence of non-radial pulsations, clearly distinct from the planetary transit signal. This raises the intriguing possibility that tides raised by the close-in planet may excite or amplify the pulsations in such stars. [ABSTRACT FROM AUTHOR]

The second known outburst of the WZ Sge type dwarf nova GW Lib was observed in 2007 April. We have obtained unique multiwavelength data of this outburst which lasted ∼26 days. The American Association of Variable Star Observers ( AAVSO) recorded the outburst in the optical, which was also monitored by Wide Angle Search for Planets, with a peak V magnitude of ∼8. The outburst was followed in the ultraviolet and X-ray wavelengths by the Swift ultraviolet/optical and X-ray telescopes. The X-ray flux at optical maximum was found to be three orders of magnitude above the pre-outburst quiescent level, whereas X-rays are normally suppressed during dwarf nova outbursts. A distinct supersoft X-ray component was also detected at optical maximum, which probably arises from an optically thick boundary layer. Follow-up Swift observations taken 1 and 2 years after the outburst show that the post-outburst quiescent X-ray flux remains an order of magnitude higher than the pre-outburst flux. The long interoutburst time-scale of GW Lib with no observed normal outbursts support the idea that the inner disc in GW Lib is evacuated or the disc viscosity is very low. [ABSTRACT FROM AUTHOR]

We present results from a search for additional transiting planets in 24 systems already known to contain a transiting planet. We model the transits due to the known planet in each system and subtract these models from light curves obtained with the SuperWASP (Wide Angle Search for Planets) survey instruments. These residual light curves are then searched for evidence of additional periodic transit events. Although we do not find any evidence for additional planets in any of the planetary systems studied, we are able to characterize our ability to find such planets by means of Monte Carlo simulations. Artificially generated transit signals corresponding to planets with a range of sizes and orbital periods were injected into the SuperWASP photometry and the resulting light curves searched for planets. As a result, the detection efficiency as a function of both the radius and orbital period of any second planet is calculated. We determine that there is a good (>50 per cent) chance of detecting additional, Saturn-sized planets in 10 d orbits around planet-hosting stars that have several seasons of SuperWASP photometry. Additionally, we confirm previous evidence of the rotational stellar variability of WASP-10, and refine the period of rotation. We find that the period of the rotation is d, and the false alarm probability for this period is extremely low . [ABSTRACT FROM AUTHOR]

We report the discovery of a 7.3 MJ exoplanet WASP-14b, one of the most massive transiting exoplanets observed to date. The planet orbits the 10th-magnitude F5V star USNO-B1 11118−0262485 with a period of 2.243 752 d and orbital eccentricity . A simultaneous fit of the transit light curve and radial velocity measurements yields a planetary mass of 7.3 ± 0.5 MJ and a radius of 1.28 ± 0.08 RJ. This leads to a mean density of about 4.6 g cm−3 making it the densest transiting exoplanets yet found at an orbital period less than 3 d. We estimate this system to be at a distance of pc. Spectral analysis of the host star reveals a temperature of cm s−2 and km s−1, and also a high lithium abundance, . The stellar density, effective temperature and rotation rate suggest an age for the system of about 0.5–1.0 Gyr. [ABSTRACT FROM AUTHOR]

We report the discovery of WASP-3b, the third transiting exoplanet to be discovered by the WASP and SOPHIE collaboration. WASP-3b transits its host star USNO-B1.0 1256−0285133 every d. Our high-precision radial velocity measurements present a variation with amplitude characteristic of a planetary-mass companion and in phase with the light curve. Adaptive optics imaging shows no evidence for nearby stellar companions, and line-bisector analysis excludes faint, unresolved binarity and stellar activity as the cause of the radial velocity variations. We make a preliminary spectroscopic analysis of the host star and find it to have and which suggests it is most likely an unevolved main-sequence star of spectral type F7-8V. Our simultaneous modelling of the transit photometry and reflex motion of the host leads us to derive a mass of and radius for WASP-3b. The proximity and relative temperature of the host star suggests that WASP-3b is one of the hottest exoplanets known, and thus has the potential to place stringent constraints on exoplanet atmospheric models. [ABSTRACT FROM AUTHOR]

The Wide Angle Search for Planets (WASP) survey currently operates two installations, designated SuperWASP-N and SuperWASP-S, located in the Northern and Southern hemispheres, respectively. These installations are designed to provide high time-resolution photometry for the purpose of detecting transiting extrasolar planets, asteroids, and transient events. Here, we present results from a transit-hunting observing campaign using SuperWASP-N covering a right ascension (RA) range of 06h < RA < 16h. This paper represents the fifth and final in the series of transit candidates released from the 2004 observing season. In total, 729 335 stars from 33 fields were monitored with 130 566 having sufficient precision to be scanned for transit signatures. Using a robust transit detection algorithm and selection criteria, six stars were found to have events consistent with the signature of a transiting extrasolar planet based on the photometry, including the known transiting planet XO-1b. These transit candidates are presented here along with discussion of follow-up observations and the expected number of candidates in relation to the overall observing strategy. [ABSTRACT FROM AUTHOR]

The Wide Angle Search for Planets (WASP) photometrically surveys a large number of nearby stars to uncover candidate extrasolar planet systems by virtue of small-amplitude light curve dips on a ≲5-d time-scale typical of the ‘Hot-Jupiters’. Observations with the SuperWASP-North instrument between 2004 April and September produced a rich photometric data set of some 1.3 × 109 data points from 6.7 million stars. Our custom-built data acquisition and processing system produces ∼0.02 mag photometric precision at . We present the transit candidates in the 03h–06h RA range. Out of 141 895 light curves with sufficient sampling to provide adequate coverage, 2688 show statistically significant transit-like periodicities. Out of these, 44 pass a visual inspection of the light curve, of which 24 are removed through a set of cuts on the statistical significance of artefacts. All but four of the remaining 20 objects are removed when prior information at higher spatial resolution from existing catalogues is taken into account. Of the four candidates remaining, one is considered a good candidate for follow-up observations with three further second-priority targets. We provide detailed information on these candidates, as well as a selection of the false-positives and astrophysical false-alarms that were eliminated, and discuss briefly the impact of sampling on our results. [ABSTRACT FROM AUTHOR]

Transiting extrasolar planets constitute only a small fraction of the range of stellar systems found to display periodic, shallow dimmings in wide-field surveys employing small-aperture camera arrays. Here we present an efficient selection strategy for follow-up observations, derived from analysis of the light curves of a sample of 67 SuperWASP targets that passed the selection tests we used in earlier papers, but which have subsequently been identified either as planet hosts or as astrophysical false positives. We determine the system parameters using Markov-chain Monte Carlo analysis of the SuperWASP light curves. We use a constrained optimization of combined with a Bayesian prior based on the main-sequence mass and radius expected from the Two Micron All Sky Survey J− H colour. The Bayesian nature of the analysis allows us to quantify both the departure of the host star from the main-sequence mass–radius relation and the probability that the companion radius is less than 1.5 Jupiter radii. When augmented by direct light-curve analyses that detect binaries with unequal primary and secondary eclipses, and objects with aperture blends that are resolved by SuperWASP, we find that only 13 of the original 67 stars, including the three known planets in the sample, would qualify for follow-up. This suggests that planet discovery ‘hit rates’ better than one-in-five should be achievable. In addition, the stellar binaries that qualify are likely to have astrophysically interesting stellar or substellar secondaries. [ABSTRACT FROM AUTHOR]

We have performed photometric observations of nearly seven million stars with with the SuperWASP-North instrument from La Palma between 2004 May to September. Fields in the right ascension range 17–18 h, yielding over 185 000 stars with sufficient quality data, have been searched for transits using a modified box least-squares (BLS) algorithm. We find a total of 58 initial transiting candidates which have high signal-to-noise ratio in the BLS, show multiple transit-like dips and have passed visual inspection. Analysis of the blending and the inferred planetary radii for these candidates leave, a total of seven transiting planet candidates which pass all the tests plus four which pass the majority. We discuss the derived parameters for these candidates and their properties and comment on the implications for future transit searches. [ABSTRACT FROM AUTHOR]

The SuperWASP-I (Wide Angle Search for Planets-I) instrument observed 6.7 million stars between 8 and 15 mag from La Palma during the 2004 May–September season. Our transit-hunting algorithm selected 11 626 objects from the 184 442 stars within the RA (right ascension) range 18–21 h. We describe our thorough selection procedure whereby catalogue information is exploited along with careful study of the SuperWASP data to filter out, as far as possible, transit mimics. We have identified 35 candidates which we recommend for follow-up observations. [ABSTRACT FROM AUTHOR]

We have detected low-amplitude radial-velocity variations in two stars, USNO-B1.0 1219–0005465 (GSC ) and USNO-B1.0 0964–0543604 (GSC ). Both stars were identified as being likely host stars of transiting exoplanets in the 2004 SuperWASP wide-field transit survey. Using the newly commissioned radial-velocity spectrograph SOPHIE at the Observatoire de Haute-Provence, we found that both objects exhibit reflex orbital radial-velocity variations with amplitudes characteristic of planetary-mass companions and in-phase with the photometric orbits. Line-bisector studies rule out faint blended binaries as the cause of either the radial-velocity variations or the transits. We perform preliminary spectral analyses of the host stars, which together with their radial-velocity variations and fits to the transit light curves yield estimates of the planetary masses and radii. WASP-1b and WASP-2b have orbital periods of 2.52 and 2.15 d, respectively. Given mass estimates for their F7V and K1V primaries, we derive planet masses 0.80–0.98 and 0.81–0.95 times that of Jupiter, respectively. WASP-1b appears to have an inflated radius of at least 1.33 RJup, whereas WASP-2b has a radius in the range 0.65–1.26 RJup. [ABSTRACT FROM AUTHOR]

We argue that the quiescent value of the viscosity parameter of the accretion disc in WZ Sge may be , in agreement with estimates of αcold for other dwarf novae. Assuming the white dwarf in WZ Sge to be magnetic, we show that, in quiescence, material close to the white dwarf can be propelled to larger radii, depleting the inner accretion disc. The propeller therefore has the effect of stabilizing the inner disc and allowing the outer disc to accumulate mass. The outbursts of WZ Sge are then regulated by the (magnetically determined) evolution of the surface density of the outer disc at a radius close to the tidal limit. Numerical models confirm that the recurrence time can be significantly extended in this way. The outbursts are expected to be superoutbursts since the outer disc radius is forced to exceed the tidal (3:1 resonance) radius. The large, quiescent disc is expected to be massive, and to be able to supply the observed mass accretion rate during outburst. We predict that the long-term spin evolution of the white dwarf spin will involve a long cycle of spin-up and spin-down phases. [ABSTRACT FROM AUTHOR]

We present a model of the stellar populations in the fields observed by one of the SuperWASP-N cameras in the 2004 observing season. We use the Besançon Galactic model to define the range of stellar types and metallicities present, and populate these objects with transiting extrasolar planets using the metallicity relation of Fischer & Valenti. We investigate the ability of SuperWASP to detect these planets in the presence of realistic levels of correlated systematic noise (‘red noise’). We find that the number of planets that transit with a signal-to-noise ratio of 10 or more increases linearly with the number of nights of observations. Based on a simulation of detection rates across 20 fields observed by one camera, we predict that a total of planets should be detectable from the SuperWASP-N 2004 data alone. The best way to limit the impact of covariant noise and increase the number of detectable planets is to boost the signal-to-noise ratio, by increasing the number of observed transits for each candidate transiting planet. This requires the observing baseline to be increased, by spending a second observing season monitoring the same fields. [ABSTRACT FROM AUTHOR]

We present a fast and efficient hybrid algorithm for selecting exoplanetary candidates from wide-field transit surveys. Our method is based on the widely used SysRem and Box Least-Squares (BLS) algorithms. Patterns of systematic error that are common to all stars on the frame are mapped and eliminated using the SysRem algorithm. The remaining systematic errors caused by spatially localized flat-fielding and other errors are quantified using a boxcar-smoothing method. We show that the dimensions of the search-parameter space can be reduced greatly by carrying out an initial BLS search on a coarse grid of reduced dimensions, followed by Newton–Raphson refinement of the transit parameters in the vicinity of the most significant solutions. We illustrate the method's operation by applying it to data from one field of the SuperWASP survey, comprising 2300 observations of 7840 stars brighter than . We identify 11 likely transit candidates. We reject stars that exhibit significant ellipsoidal variations caused indicative of a stellar-mass companion. We use colours and proper motions from the Two Micron All Sky Survey and USNO-B1.0 surveys to estimate the stellar parameters and the companion radius. We find that two stars showing unambiguous transit signals pass all these tests, and so qualify for detailed high-resolution spectroscopic follow-up. [ABSTRACT FROM AUTHOR]

Photometric transit surveys promise to complement the currently known sample of extra-solar planets (ESPs) by providing additional information on the planets and especially their radii. Here, we present ESP candidates from one such survey called, the Wide Angle Search for Planets (WASP) obtained with the SuperWASP wide-field imaging system. Observations were taken with SuperWASP North located in La Palma during the 2004 April to October observing season. The data cover fields between 23 and 03 h in RA at declinations above +12. This amounts to over ≈400 000 stars with V magnitudes 8–13.5. For the stars brighter than 12.5, we achieve better than 1 per cent photometric precision. Here, we present 41 sources with low-amplitude variability between ≈1 and 10 mmag, from which we select 12 with periods between 1.2 and 4.4 d as the most promising ESP candidates. We discuss the properties of these ESP candidates, the expected fraction of transits recovered for our sample and implications for the frequency and detection of hot-Jupiters. [ABSTRACT FROM AUTHOR]

Observations of accreting systems often show significant variability (10–20 per cent of accretion luminosity) on time-scales much longer than expected for the disc regions releasing most of the luminosity. We propose an explicit physical model for disc variability, consistent with Lyubarskii's general scheme for solving this problem. We suggest that local dynamo processes can affect the evolution of an accretion disc by driving angular momentum loss in the form of an outflow (a wind or jet). We model the dynamo as a small-scale stochastic phenomenon, operating on roughly the local dynamical time-scale. We argue that large-scale outflow can only occur when the small-scale random processes in neighbouring disc annuli give rise by chance to a coherent large-scale magnetic field. This occurs on much longer time-scales, and causes a bright large-amplitude flare as a wide range of disc radii evolve in a coherent fashion. Most of the time, dynamo action instead produces small-amplitude flickering. We reproduce power spectra similar to those observed, including a 1/ f power spectrum below a break frequency given by the magnetic alignment time-scale at the inner disc edge. However, the relation between the black hole mass and the value of the break frequency is less straightforward than often assumed in the literature. The effect of an outer disc edge is to flatten the spectrum below the magnetic alignment frequency there. We also find a correlation between the variability amplitude and luminosity, similar to that found in some active galactic nuclei. [ABSTRACT FROM AUTHOR]

A correction to the article "The Super WASP wide-field exoplanetary transit survey: candidates from fields 23 h < RA < 03 h," by D.J. Christian, D.L. Pollacco and colleagues, featured in a 2006 issue of the journal, is presented.

The Wide Angle Search for Planets (WASP) survey currently operates two installations, designated SuperWASP-N and SuperWASP-S, located in the Northern and Southern hemispheres, respectively. These installations are designed to provide high time-resolution photometry for the purpose of detecting transiting extrasolar planets, asteroids, and transient events. Here, we present results from a transit-hunting observing campaign using SuperWASP-N covering a right ascension (RA) range of 06h < RA < 16h. This paper represents the fifth and final in the series of transit candidates released from the 2004 observing season. In total, 729 335 stars from 33 fields were monitored with 130 566 having sufficient precision to be scanned for transit signatures. Using a robust transit detection algorithm and selection criteria, six stars were found to have events consistent with the signature of a transiting extrasolar planet based on the photometry, including the known transiting planet XO-1b. These transit candidates are presented here along with discussion of follow-up observations and the expected number of candidates in relation to the overall observing strategy. [ABSTRACT FROM AUTHOR]

The Wide Angle Search for Planets (WASP) photometrically surveys a large number of nearby stars to uncover candidate extrasolar planet systems by virtue of small-amplitude light curve dips on a ≲5-d time-scale typical of the ‘Hot-Jupiters’. Observations with the SuperWASP-North instrument between 2004 April and September produced a rich photometric data set of some 1.3 × 109 data points from 6.7 million stars. Our custom-built data acquisition and processing system produces ∼0.02 mag photometric precision at . We present the transit candidates in the 03h–06h RA range. Out of 141 895 light curves with sufficient sampling to provide adequate coverage, 2688 show statistically significant transit-like periodicities. Out of these, 44 pass a visual inspection of the light curve, of which 24 are removed through a set of cuts on the statistical significance of artefacts. All but four of the remaining 20 objects are removed when prior information at higher spatial resolution from existing catalogues is taken into account. Of the four candidates remaining, one is considered a good candidate for follow-up observations with three further second-priority targets. We provide detailed information on these candidates, as well as a selection of the false-positives and astrophysical false-alarms that were eliminated, and discuss briefly the impact of sampling on our results. [ABSTRACT FROM AUTHOR]