The WASP Project and SuperWASP Camera

The WASP project and infrastructure supporting the SuperWASP Facility are described. As the instrument, reduction pipeline and archive system are now fully operative we expect the system to have a major impact in the discovery of bright exo-planet candidates as well in more general variable star projects.

SuperWASP-North extrasolar planet candidates: candidates from fields 17h

We have performed photometric observations of nearly seven million stars with 8 <V <15 with the SuperWASP-North instrument from La Palma between 2004 May to September. Fields in the right ascension range 17-18h, yielding over 185000 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.

SuperWASP-N extrasolar planet candidates between 18 <RA <21h

The SuperWASP-I (Wide Angle Search for Planets-I) instrument observed 6.7 million stars between 8 and 15mag from La Palma during the 2004 May-September season. Our transit-hunting algorithm selected 11626 objects from the 184442 stars within the RA (right ascension) range 18-21h. 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.

SuperWASP-North extrasolar planet candidates between 3h <RA <6h

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

SuperWASP-N extrasolar planet candidates from fields 06h

TheWide 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.

WASP-3b: a strongly irradiated transiting gas-giant planet

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-B1.01256-0285133 every 1.846834 +/- 0.000002 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 Teff = 6400 +/- 100K and log g = 4.25 +/- 0.05 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 1.76+0.08-0.14 MJ and radius 1.31+0.07-0.14 RJ 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.

Energy levels, radiative rates, and excitation rates for transitions in OIV

Aims. In this paper we report calculations for energy levels, radiative rates, and excitation rates for transitions in O IV. Methods. The grasp (general-purpose relativistic atomic structure package) and FAC (flexible atomic code) were adopted for calculating energy levels and radiative rates, and the Dirac atomic R-matrix code (DARC) used to determine the excitation rates. Results. Oscillator strengths and radiative rates are reported for all E1, E2, M1, and M2 transitions among the lowest 75 levels of O IV. Additionally, lifetimes are reported for all levels and comparisons made with those available in the literature. Finally, effective collision strengths are reported for all transitions over a wide temperature range below 106 K. Comparisons are made with earlier results and the accuracy of the data is assessed.

Radiative rates and electron impact excitation rates for H-like Ar XVIII

Aims. In this paper we report on calculations for energy levels, radiative rates, collision strengths, and effective collision strengths for
transitions among the lowest 25 levels of the n ≤ 5 configurations of H-like Ar xviii.
Methods. The general-purpose relativistic atomic structure package (grasp) andDirac atomic R-matrix code (darc) are adopted for
the calculations.
Results. Radiative rates, oscillator strengths, and line strengths are reported for all electric dipole (E1), magnetic dipole (M1), electric
quadrupole (E2), and magnetic quadrupole (M2) transitions among the 25 levels. Furthermore, collision strengths and effective
collision strengths are listed for all 300 transitions among the above 25 levels over a wide energy (temperature) range up to 800 Ryd
(107.4 K).

Transition region velocity oscillations observed by EUNIS-06

Spectroscopic measurements of NOAA AR 10871, obtained with the Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS) sounding rocket instrument on 2006 April 12, reveal velocity oscillations in the He II 303.8 angstrom emission line formed at T approximate to 5; 10(4) K. The oscillations appear to arise in a bright active region loop arcade about 25 '' wide which crosses the EUNIS slit. The period of these transition region oscillations is 26 +/- 4 s, coupled with a velocity amplitude of +/- 10 km s(-1), detected over four complete cycles. Similar oscillations are observed in lines formed at temperatures up to T approximate to 4; 10(5) K, but we find no evidence for the coupling of these velocity oscillations with corresponding phenomena in the corona. We interpret the detected oscillations as originating from an almost purely adiabatic plasma, and infer that they are generated by the resonant transmission of MHD waves through the lower active region atmospheres. Through the use of seismological techniques, we establish that the observed velocity oscillations display wave properties most characteristic of fast body global sausage modes.

Discovery of Spatial Periodicities in a Coronal Loop Using Automated Edge-Tracking Algorithms

A new method for automated coronal loop tracking, in both spatial and temporal domains, is presented. Applying this technique to TRACE data, obtained using the 171 angstrom filter on 1998 July 14, we detect a coronal loop undergoing a 270 s kink-mode oscillation, as previously found by Aschwanden et al. However, we also detect flare-induced, and previously unnoticed, spatial periodicities on a scale of 3500 km, which occur along the coronal loop edge. Furthermore, we establish a reduction in oscillatory power for these spatial periodicities of 45% over a 222 s interval. We relate the reduction in detected oscillatory power to the physical damping of these loop-top oscillations.

Line intensity enhancements in stellar coronal X-ray spectra due to opacity effects

Context. The I(15.01 Å)/I(16.78 Å) emission line intensity ratio in Fe xvii has been reported to deviate from its theoretical value
in solar and stellar X-ray spectra. This is attributed to opacity in the 15.01 Å line, leading to a reduction in its intensity, and was
interpreted in terms of a geometry in which the emitters and absorbers are spatially distinct.
Aims. We study the I(15.01 Å)/I(16.78 Å) intensity ratio for the active cool dwarf EV Lac, in both flare and quiescent spectra.
Methods. The observations were obtained with the Reflection Grating Spectrometer on the XMM-Newton satellite. The emission
measure distribution versus temperature reconstruction technique is used for our analysis.
Results. We find that the 15.01 Å line exhibits a significant enhancement in intensity over the optically thin value. To our knowledge,
this is the first time that such an enhancement has been detected on such a sound statistical basis. We interpret this enhancement
in terms of a geometry in which the emitters and absorbers are not spatially distinct, and where the geometry is such that resonant
pumping of the upper level has a greater effect on the observed line intensity than resonant absorption in the line-of-sight.

Energy levels and radiative rates for transitions in B-like to F-like Kr ions (Kr XXXII-XXVIII)

Energy levels, radiative rates, oscillator strengths, line strengths, and lifetimes have been calculated for transitions in B-like to F-like Kr ions, Kr XXXIII-XXVIII. For the calculations, the fully relativistic GRASP code has been adopted, and results are reported for all electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2) transitions among the lowest 125, 236, 272, 226, and 113 levels of Kr XXXII, Kr XXXI, Kr XXX, Kr XXIX, and Kr XXVIII, respectively, belonging to the n