Search

We present an optical transmission spectrum for WASP-94A b, the first atmospheric characterisation of this highly-inflated hot Jupiter. The planet has a reported radius of $1.72^{+0.06}_{-0.05}$ R$_{\textrm{Jup}}$, a mass of only $0.456^{+0.032}_{-0.036}$ M$_{\textrm{Jup}}$, and an equilibrium temperature of $1508 \pm 75$ K. We observed the planet transit spectroscopically with the EFOSC2 instrument on the ESO New Technology Telescope (NTT) at La Silla, Chile: the first use of NTT/EFOSC2 for transmission spectroscopy. We achieved an average transit-depth precision of $128$ ppm for bin widths of $\sim200$ Angstrom. This high precision was achieved in part by linking Gaussian Process hyperparameters across all wavelength bins. The resulting transmission spectrum, spanning a wavelength range of $3800 - 7140$ Angstrom, exhibits a sodium absorption with a significance of $4.9\sigma$, suggesting a relatively cloud-free atmosphere. The sodium signal may be broadened, with a best fitting width of $78_{-32}^{+67}$ Angstrom in contrast to the instrumental resolution of $27.2 \pm 0.2$ Angstrom. We also detect a steep slope in the blue end of the transmission spectrum, indicating the presence of Rayleigh scattering in the atmosphere of WASP-94A b. Retrieval models show evidence for the observed slope to be super-Rayleigh and potential causes are discussed. Finally, we find narrow absorption cores in the CaII H&K lines of WASP-94A, suggesting the star is enshrouded in gas escaping the hot Jupiter., 16 pages, 15 figures, 6 tables, accepted for publication in MNRAS

Magnetic interactions between stars and close-in planets may lead to a detectable signal on the stellar disk. HD 189733 is one of the key exosystems thought to harbor magnetic interactions, which may have been detected in August 2013. We present a set of twelve wind models at that period, covering the possible coronal states and coronal topologies of HD 189733 at that time. We assess the power available for the magnetic interaction and predict its temporal modulation. By comparing the predicted signal with the observed signal, we find that some models could be compatible with an interpretation based on star-planet magnetic interactions. We also find that the observed signal can be explained only with a stretch-and-break interaction mechanism, while that the Alfv\'en wings scenario cannot deliver enough power. We finally demonstrate that the past observational cadence of HD 189733 leads to a detection rate of only between 12 to 23%, which could explain why star-planet interactions have been hard to detect in past campaigns. We conclude that the firm confirmation of their detection will require dedicated spectroscopic observations covering densely the orbital and rotation period, combined with scarcer spectropolarimetric observations to assess the concomitant large-scale magnetic topology of the star., Comment: 16 pages, 8 figures, 4 tables, accepted for publication in MNRAS

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.--Full list of authors: Barragan, O.; Armstrong, D. J.; Gandolfi, D.; Carleo, I; Vidotto, A. A.; D'Angelo, C. Villarreal; Oklopcic, A.; Isaacson, H.; Oddo, D.; Collins, K.; Fridlund, M.; Sousa, S. G.; Persson, C. M.; Hellier, C.; Howell, S.; Howard, A.; Redfield, S.; Eisner, N.; Georgieva, I. Y.; Dragomir, D.; Bayliss, D.; Nielsen, L. D.; Klein, B.; Aigrain, S.; Zhang, M.; Teske, J.; Twicken, J. D.; Jenkins, J.; Esposito, M.; Van Eylen, V.; Rodler, F.; Adibekyan, V; Alarcon, J.; Anderson, D. R.; Murphy, J. M. Akana; Barrado, D.; Barros, S. C. C.; Benneke, B.; Bouchy, F.; Bryant, E. M.; Butler, R. P.; Burt, J.; Cabrera, J.; Casewell, S.; Chaturvedi, P.; Cloutier, R.; Cochran, W. D.; Crane, J.; Crossfield, I; Crouzet, N.; Collins, K., I; Dai, F.; Deeg, H. J.; Deline, A.; Demangeon, O. D. S.; Dumusque, X.; Figueira, P.; Furlan, E.; Gnilka, C.; Goad, M. R.; Goffo, E.; Gutierrez-Canales, F.; Hadjigeorghiou, A.; Hartman, Z.; Hatzes, A. P.; Harris, M.; Henderson, B.; Hirano, T.; Hojjatpanah, S.; Hoyer, S.; Kabath, P.; Korth, J.; Lillo-Box, J.; Luque, R.; Marmier, M.; Mocnik, T.; Muresan, A.; Murgas, F.; Nagel, E.; Osborne, H. L. M.; Osborn, A.; Osborn, H. P.; Palle, E.; Raimbault, M.; Ricker, G. R.; Rubenzahl, R. A.; Stockdale, C.; Santos, N. C.; Scott, N.; Schwarz, R. P.; Shectman, S.; Seager, S.; Segransan, D.; Serrano, L. M.; Skarka, M.; Smith, A. M. S.; Subjak, J.; Tan, T. G.; Udry, S.; Watson, C.; Wheatley, P. J.; West, R.; Winn, J. N.; Wang, S. X.; Wolfgang, A.; Ziegler, C.; KESPRINT Team., We present the discovery and characterization of two transiting planets observed by TESS in the light curves of the young and bright (V = 9.67) star HD73583 (TOI-560). We perform an intensive spectroscopic and photometric space- and ground-based follow-up in order to confirm and characterize the system. We found that HD73583 is a young (∼500 Myr) active star with a rotational period of 12.08 ± 0.11 d, and a mass and radius of 0.73 ± 0.02 M⊙ and 0.65 ± 0.02 R⊙, respectively. HD 73583 b (Pb = 6.3980420+0.0000067−0.0000062 d) has a mass and radius of 10.2+3.4−3.1 M⊕ and 2.79 ± 0.10 R⊕, respectively, which gives a density of 2.58+0.95−0.81 gcm−3⁠. HD 73583 c (Pc = 18.87974+0.00086−0.00074 d) has a mass and radius of 9.7+1.8−1.7 M⊕ and 2.39+0.10−0.09 R⊕, respectively, which translates to a density of 3.88+0.91−0.80 gcm−3⁠. Both planets are consistent with worlds made of a solid core surrounded by a volatile envelope. Because of their youth and host star brightness, they both are excellent candidates to perform transmission spectroscopy studies. We expect ongoing atmospheric mass-loss for both planets caused by stellar irradiation. We estimate that the detection of evaporating signatures on H and He would be challenging, but doable with present and future instruments. © The Author(s) 2022. Published by Oxford University Press on behalf of Royal Astronomical Society., This work was supported by the KESPRINT collaboration, an international consortium devoted to the characterization and research of exoplanets discovered with space-based missions (http://www.kesprint.science). We thank the referee for their helpful comments and suggestions that improved the quality of this manuscript. We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This work uses observations from the LCOGT network. Part of the LCOGT telescope time was granted by NOIRLab through the Mid-Scale Innovations Program (MSIP). MSIP is funded by NSF. This paper is in part based on data collected under the NGTS project at the ESO La Silla Paranal Observatory. The NGTS facility is operated by the consortium institutes with support from the UK Science and Technology Facilities Council (STFC) projects ST/M001962/1 and ST/S002642/1. This research has used the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Some of the observations in the paper used the High-Resolution Imaging instrument Zorro obtained under Gemini LLP Proposal Number: GN/S-2021A-LP-105. Zorro was funded by the NASA Exoplanet Exploration Program and built at the NASA Ames Research Center by Steve B. Howell, Nic Scott, Elliott P. Horch, and Emmett Quigley. Zorro was mounted on the Gemini North (and/or South) telescope of the international Gemini Observatory, a program of NSF’s OIR Lab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation on behalf of the Gemini partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). OB, BK, and SA acknowledge that this publication is part of a project that has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement No. 865624). DG and LMS gratefully acknowledge financial support from the Cassa di Risparmio di Torino foundation under Grant No. 2018.2323 ‘Gaseous or rocky? Unveiling the nature of small worlds’. DJA acknowledges support from the STFC via an Ernest Rutherford Fellowship (ST/R00384X/1). APH and ME acknowledges grant HA 3279/12-1 within the DFG Schwerpunkt SPP 1992, ‘Exploring the Diversity of Extrasolar Planets’. JS and PK would like to acknowledge support from MSMT grant LTT-20015. We acknowledges the support by FCT – Fundação para a Ciência e a Tecnologia through national funds and by FEDER through COMPETE2020 – Programa Operacional Competitividade e Internacionalização by these grants: UID/FIS/04434/2019; UIDB/04434/2020; UIDP/04434/2020; PTDC/FIS-AST/32113/2017 & POCI-01-0145-FEDER-032113; PTDC/FISAST /28953/2017 & POCI-01-0145-FEDER-028953. AD acknowledges the financial support of the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (project FOUR ACES; grant agreement No 724427). AD also acknowledges financial support of the the Swiss National Science Foundation (SNSF) through the National Centre for Competence in Research ‘PlanetS’. MF, IYG, JK, and CMP gratefully acknowledge the support of the Swedish National Space Agency (DNR 177/19, 174/18, 2020-00104, 65/19). FGC thanks the Mexican national council for science and technology (CONACYT, CVU-1005374). MS acknowledge financial support of the Inter-transfer grant no LTT-20015. JL-B acknowledges financial support received from ‘la Caixa’ Foundation (ID 100010434) and from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 847648, with fellowship code LCF/BQ/PI20/11760023. AAV acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 817540, ASTROFLOW). JMAM is supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1842400. JMAM acknowledges the LSSTC Data Science Fellowship Program, which is funded by LSSTC, NSF Cybertraining Grant No. 1829740, the Brinson Foundation, and the Moore Foundation; his participation in the program has benefited this work. RAR is supported by the NSF Graduate Research Fellowship, grant No. DGE 1745301. RL acknowledges financial support from the Spanish Ministerio de Ciencia e Innovación, through project PID2019-109522GB-C52, and the Centre of Excellence ‘Severo Ochoa’ award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). PC acknowledges the generous support from Deutsche Forschungsgemeinschaft (DFG) of the grant CH 2636/1-1. SH acknowledges CNES funding through the grant 837319. VA acknowledges the support from Fundação para a Ciência e Tecnologia (FCT) through Investigador FCT contract nr. IF/00650/2015/CP1273/CT0001. ODSD is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by national funds through Fundação para a Ciência e Tecnologia (FCT). AO is supported by an STFC studentship. XD would like to acknowledge the funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement SCORE No 851555). HJD acknowledges support from the Spanish Research Agency of the Ministry of Science and Innovation (AEI-MICINN) under the grant ‘Contribution of the IAC to the PLATO Space Mission’ with reference PID2019-107061GB-C66, DOI: 10.13039/501100011033. DD acknowledges support from the TESS Guest Investigator Program grant 80NSSC19K1727 and NASA Exoplanet Research Program grant 18-2XRP18_2-0136. AO gratefully acknowledges support from the Dutch Research Council NWO Veni grant.

Full list of authors: Lillo-Box, J.; Gandolfi, D.; Armstrong, D. J.; Collins, K. A.; Nielsen, L. D.; Luque, R.; Korth, J.; Sousa, S. G.; Quinn, S. N.; Acuña, L.; Howell, S. B.; Morello, G.; Hellier, C.; Giacalone, S.; Hoyer, S.; Stassun, K.; Palle, E.; Aguichine, A.; Mousis, O.; Adibekyan, V.; Azevedo Silva, T.; Barrado, D.; Deleuil, M.; Eastman, J. D.; Fukui, A.; Hawthorn, F.; Irwin, J. M.; Jenkins, J. M.; Latham, D. W.; Muresan, A.; Narita, N.; Persson, C. M.; Santerne, A.; Santos, N. C.; Savel, A. B.; Osborn, H. P.; Teske, J.; Wheatley, P. J.; Winn, J. N.; Barros, S. C. C.; Butler, R. P.; Caldwell, D. A.; Charbonneau, D.; Cloutier, R.; Crane, J. D.; Demangeon, O. D. S.; Díaz, R. F.; Dumusque, X.; Esposito, M.; Falk, B.; Gill, H.; Hojjatpanah, S.; Kreidberg, L.; Mireles, I.; Osborn, A.; Ricker, G. R.; Rodriguez, J. E.; Schwarz, R. P.; Seager, S.; Serrano Bell, J.; Shectman, S. A.; Shporer, A.; Vezie, M.; Wang, S. X.; Zhou, G.--This is an Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., Context. The current architecture of a given multi-planetary system is a key fingerprint of its past formation and dynamical evolution history. Long-term follow-up observations are key to complete their picture. Aims. In this paper, we focus on the confirmation and characterization of the components of the TOI-969 planetary system, where TESS detected a Neptune-size planet candidate in a very close-in orbit around a late K-dwarf star. Methods. We use a set of precise radial velocity observations from HARPS, PFS, and CORALIE instruments covering more than two years in combination with the TESS photometric light curve and other ground-based follow-up observations to confirm and characterize the components of this planetary system. Results. We find that TOI-969 b is a transiting close-in (Pb ~ 1.82 days) mini-Neptune planet (mb = 9.1−1.0+1.1 M⊕, Rb = 2.765−0.097+0.088 R⊕), placing it on the lower boundary of the hot-Neptune desert (Teq,b = 941 ± 31 K). The analysis of its internal structure shows that TOI-969 b is a volatile-rich planet, suggesting it underwent an inward migration. The radial velocity model also favors the presence of a second massive body in the system, TOI-969 c, with a long period of Pc = 1700−280+290 days, a minimum mass of mc sin ic = 11.3−0.9+1.1 MJup, and a highly eccentric orbit of ec = 0.628−0.036+0.043. Conclusions. The TOI-969 planetary system is one of the few around K-dwarfs known to have this extended configuration going from a very close-in planet to a wide-separation gaseous giant. TOI-969 b has a transmission spectroscopy metric of 93 and orbits a moderately bright (G = 11.3 mag) star, making it an excellent target for atmospheric studies. The architecture of this planetary system can also provide valuable information about migration and formation of planetary systems. © The Authors 2023., J.L-B. acknowledges financial support received from “la Caixa” Foundation (ID 100010434) and from the European Unions Horizon 2020 research and innovation programme under the Marie Slodowska-Curie grant agreement No 847648, with fellowship code LCF/BQ/PI20/11760023. This research has also been partly funded by the Spanish State Research Agency (AEI) Projects No.PID2019-107061GB-C6l and No. MDM-2017-0737 Unidad de Excelencia “Maria de Maeztu” – Centro de Astrobiología (INTA-CSIC). R.L. acknowledges financial support from the Spanish Ministerio de Ciencia e Innovación, through project PID2019-109522GB-C52, and the Centre of Excellence “Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). DJ.A. acknowledges support from the STFC via an Ernest Rutherford Fellowship (ST/R00384X/1). S.G.S acknowledges the support from FCT through Estimulo FCT contract nr.CEECIND/00826/2018 and POPH/FSE (EC). G.M. has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 895525. S.H. acknowledges CNES funding through the grant 837319. The French group acknowledges financial support from the French Programme National de Planétologie (PNP, INSU). This work is partly financed by the Spanish Mnistry of Economics and Competitiveness through grants PGC2018-098153-B-C31. We acknowledge the support by FCT – Fundação para a Ciência e a Tecnologia through national funds and by FEDER through COMPETE2020 – Programa Operacional Competitividade e Internacionalização by these grants: UID/FIS/04434/2019; UIDB/04434/2020; UIDP/04434/2020; PTDC/FIS-AST/32113/2017 & POCI-01-0145-FEDER-032113; PTDC/FISAST/28953/2017 & POCI-01-0145-FEDER-028953. P.J.W is supported by an STFC consolidated grant (ST/T000406/1). F.H. is funded by an STFC studentship. T.A.S acknowledges support from the Fundação para a Ciência e a Tecnologia (FCT) through the Fellowship PD/BD/150416/2019 and POCH/FSE (EC). C.M.P. acknowledges support from the SNSA (dnr 65/19P). This work has been carried out within the framework of the National Centre of Competence in Research (NCCR) PlanetS supported by the Swiss National Science Foundation. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement SCORE No 851555). O.D.S.D. is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by national funds through Fundação para a Ciência e a Tecnologia (FCT). M.E. acknowledges the support of the DFG priority programSPP 1992 “Exploring the Diversity of Extrasolar Planets” (HA 3279/12-1). A.O. is funded by an STFC studentship. J.K. gratefully acknowledge the support of the Swedish National Space Agency (SNSA; DNR 2020-00104). This work makes use of observations from the LCOGT network. This paper is based on observations made with the MuSCAT3 instrument, developed by the Astrobiology Center and under financial supports by ISPS KAKENHI (IP18H05439) and 1ST PRESTO (IPMIPR1775), at Faulkes Telescope North on Maui, HI, operated by the Las Cumbres Observatory. Some of the observations in the paper made use of the High-Resolution Imaging instrument Zorro obtained under Gemini LLP Proposal Number: GN/S-2021A-LP-105. Zorro was funded by the NASA Exoplanet Exploration Program and built at the NASA Ames Research Center by Steve B. Howell, Nie Scott, Elliott P. Horch, and Emmett Quigley. Zorro was mounted on the Gemini North (and/or South) telescope of the international Gemini Observatory, a program of NSF’s OIR Lab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. on behalf of the Gemini partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. The MEarth Team gratefully acknowledges funding from the David and Lucile Packard Fellowship for Science and Engineering (awarded to D.C.). This material is based upon work supported by the National Science Foundation under grants AST-0807690, AST-1109468, AST-1004488 (Alan T. Waterman Award), and AST-1616624, and upon work supported by the National Aeronautics and Space Administration under Grant No. 80NSSC18K0476 issued through the XRP Program. This work is made possible by a grant from the John Templeton Foundation. The opinions expressed in this publication are those of the authors and do not necessarily reflect the views of the John Templeton Foundation. This research made use of Astropy, (a community-developed core Python package for Astronomy, Astropy Collaboration 2013, 2018), SciPy (Virtanen et al. 2020), matplotlib (a Python library for publication quality graphics Hunter 2007), and numpy (Harris et al. 2020). This research has made use of NASA’s Astrophysics Data System Bibliographic Services. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France., With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001131-S).

Despite being bright ($V=12$) and nearby ($d=212$ pc) ASAS J071404+7004.3 has only recently been identified as a nova-like cataclysmic variable. We present time-resolved optical spectroscopy obtained at the Isaac Newton Telescope together with $\textit{Swift}$ X-ray and ultraviolet observations. We combined these with $\textit{TESS}$ photometry and find a period of 3.28h and a mass transfer rate of $4-9 \times 10^{-9} M_{sun}/yr$. Historical photometry shows at least one low state establishing the system as a VY Scl star. Our high-cadence spectroscopy also revealed rapidly changing winds emanating from the accretion disc. We have modelled these using the Monte Carlo PYTHON code and shown that all the emission lines could emanate from the wind - which would explain the lack of double-peaked lines in such systems. In passing,we discuss the effect of variability on the position of cataclysmic variables in the $\textit{Gaia}$ Hertzsprung-Russell diagram., Accepted for publication by MNRAS. 20 pages, 14 figures

We report the discovery of two transiting exoplanets from the WASP survey, WASP-150b and WASP-176b. WASP-150b is an eccentric ($e$ = 0.38) hot Jupiter on a 5.6 day orbit around a $V$ = 12.03, F8 main-sequence host. The host star has a mass and radius of 1.4 $\rm M_{\odot}$ and 1.7 $\rm R_{\odot}$ respectively. WASP-150b has a mass and radius of 8.5 $\rm M_J$ and 1.1 $\rm R_J$, leading to a large planetary bulk density of 6.4 $\rm \rho_J$. WASP-150b is found to be $\sim3$ Gyr old, well below its circularisation timescale, supporting the eccentric nature of the planet. WASP-176b is a hot Jupiter planet on a 3.9 day orbit around a $V$ = 12.01, F9 sub-giant host. The host star has a mass and radius of 1.3 $\rm M_{\odot}$ and 1.9 $\rm R_{\odot}$. WASP-176b has a mass and radius of 0.86 $\rm M_J$ and 1.5 $\rm R_J$ respectively, leading to a planetary bulk density of 0.23 $\rm \rho_J$., Comment: 15 pages, 14 figures. Accepted for publication in The Astronomical Journal

International audience; Aims. We present the discovery and characterisation of the exoplanets WASP-113b and WASP-114b by the WASP surveys, SOPHIE and CORALIE. Methods. The planetary nature of the systems was established by performing follow-up photometric and spectroscopic observations. The follow-up data were combined with the WASP-photometry and analysed with an MCMC code to obtain system parameters. Results. The host stars WASP-113 and WASP-114 are very similar. They are both early G-type stars with an effective temperature of similar to 5900 K, [Fe/H] similar to 0.12, and log g similar to 4.1 dex. However, WASP-113 is older than WASP-114. Although the planetary companions have similar radii, WASP-114b is almost four times heavier than WASP-113b. WASP-113b has a mass of 0.48 M-Jup and an orbital period of similar to 4.5 days; WASP-114b has a mass of 1.77 M-Jup and an orbital period of similar to 1.5 days. Both planets have inflated radii, in particular WASP-113 with a radius anomaly of R = 0.35. The high scale height ofWASP-113b (similar to 950 km) makes it a good target for follow-up atmospheric observations.

[Aims] X-ray sources at intermediate fluxes (a few x 10-14 erg cm-2 s-1) with a sky density of ~100 deg-2 are responsible for a significant fraction of the cosmic X-ray background at various energies below 10 keV. The aim of this paper is to provide an unbiased and quantitative description of the X-ray source population at these fluxes and in various X-ray energy bands., [Methods] We present the XMM-Newton Medium sensitivity Survey (XMS), including a total of 318 X-ray sources found among the serendipitous content of 25 XMM-Newton target fields. The XMS comprises four largely overlapping source samples selected at soft (0.5-2 keV), intermediate (0.5-4.5 keV), hard (2-10 keV) and ultra-hard (4.5-7.5 keV) bands, the first three of them being flux-limited., [Results] We report on the optical identification of the XMS samples, complete to 85-95%. At the flux levels sampled by the XMS we find that the X-ray sky is largely dominated by Active Galactic Nuclei. The fraction of stars in soft X-ray selected samples is below 10%, and only a few per cent for hard selected samples. We find that the fraction of optically obscured objects in the AGN population stays constant at around 15-20% for soft and intermediate band selected X-ray sources, over 2 decades of flux. The fraction of obscured objects amongst the AGN population is larger (~35-45%) in the hard or ultra-hard selected samples, and constant across a similarly wide flux range. The distribution in X-ray-to-optical flux ratio is a strong function of the selection band, with a larger fraction of sources with high values in hard selected samples. Sources with X-ray-to-optical flux ratios in excess of 10 are dominated by obscured AGN, but with a significant contribution from unobscured AGN., Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and the USA (NASA). Based on observations made with the INT/WHT, TNG and NOT operated on the island of La Palma by the Isaac Newton Group, the Centro Galileo Galilei and ESA Member States and the USA (NASA). Based on observations made with the INT/WHT, TNG and NOT operated on the island of La Palma by the Isaac Newton Group, the Centro Galileo Galilei and the Nordic Optical Telescope Science Association respectively, in the Spanish Observatorio del Roque de los Muchachos. Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC). Based on observations collected at the European Southern Observatory, Paranal, Chile, as part of programme 75.A-0336.

We have performed photometric observations of nearly 7 million stars with 8 < V < 15 with the SuperWASP-North instrument from La Palma between 2004 May-September. Fields in the RA range 17-18hr, 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 S/N in the BLS, show multiple transit-like dips and have passed visual inspection. Analysis of the blending and inferred planetary radii for these candidates leaves a total of 7 transiting planet candidates which pass all the tests plus 4 which pass the majority. We discuss the derived parameters for these candidates and their properties and comment on the implications for future transit searches., Comment: 17 pages, 24 figures, accepted by MNRAS

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 Besancon Galactic model to define the range of stellar types and metallicities present, and populate these objects with transiting extra-solar planets using the metallicity relation of Fischer & Valenti (2005). 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 18.6 \pm 8.0 planets should be detectable from the SuperWASP-N 2004 data alone. The best way to limit the impact of co-variant 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., Omitted co-authors reinstated. 9 pages, 7 figures, accepted for publication in MNRAS

The TRAPPIST-1 system offers the opportunity to characterize terrestrial, potentially habitable planets orbiting a nearby ultracool dwarf star. We performed a four-orbit reconnaissance with the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope to study the stellar emission at Lyman-$\alpha$, to assess the presence of hydrogen exospheres around the two inner planets, and to determine their UV irradiation. We detect the Lyman-$\alpha$ line of TRAPPIST-1, making it the coldest exoplanet host star for which this line has been measured. We reconstruct the intrinsic line profile, showing that it lacks broad wings and is much fainter than expected from the stellar X-ray emission. TRAPPIST-1 has a similar X-ray emission as Proxima Cen but a much lower Ly-$\alpha$ emission. This suggests that TRAPPIST-1 chromosphere is only moderately active compared to its transition region and corona. We estimated the atmospheric mass loss rates for all planets, and found that despite a moderate extreme UV emission the total XUV irradiation could be strong enough to strip the atmospheres of the inner planets in a few billions years. We detect marginal flux decreases at the times of TRAPPIST-1b and c transits, which might originate from stellar activity, but could also hint at the presence of extended hydrogen exospheres. Understanding the origin of these Lyman-$\alpha$ variations will be crucial in assessing the atmospheric stability and potential habitability of the TRAPPIST-1 planets., Comment: Published in A&A as a Letter to the Editor

We observed the extreme close-in hot Jupiter system WASP-12 with HST. Near-UV transits up to three times deeper than the optical transit of WASP-12b reveal extensive diffuse gas, extending well beyond the Roche lobe. The distribution of absorbing gas varies between visits. The deepest NUV transits are at wavelength ranges with strong photospheric absorption, implying the absorbing gas may have temperature and composition similar to the stellar photosphere. Our spectra reveal significantly enhanced absorption (greater than 3 \sigma below the median) at ~200 wavelengths on each of two HST visits; 65 of these wavelengths are consistent between the two visits, using a strict criterion for velocity matching which excludes matches with velocity shifts exceeding ~20 km/s. Excess transit depths are robustly detected throughout the inner wings of the MgII resonance lines independently on both HST visits. We detected absorption in FeII 2586A, the heaviest species yet detected in an exoplanet transit. The MgII line cores have zero flux, emission cores exhibited by every other observed star of similar age and spectral type are conspicuously absent. WASP-12 probably produces normal MgII profiles, but the inner portions of these strong resonance lines are likely affected by extrinsic absorption. The required Mg+ column is an order of magnitude greater than expected from the ISM, though we cannot completely dismiss that possibility. A more plausible source of absorption is gas lost by WASP-12b. We show that planetary mass loss can produce the required column. Our Visit 2 NUV light curves show evidence for a stellar flare. We show that some of the possible transit detections in resonance lines of rare elements may be due instead to non-resonant transitions in common species. We present optical observations and update the transit ephemeris., Comment: 79 pages, 23 figures, published in ApJ "replaced" version is identical except for corrected punctuation in the arXiv abstract

Aims. We observe occultations of WASP-24b to measure brightness temperatures and to determine whether or not its atmosphere exhibits a thermal inversion (stratosphere). Methods. We observed occultations of WASP-24b at 3.6 and 4.5 {\mu}m using the Spitzer Space Telescope. It has been suggested that there is a correlation between stellar activity and the presence of inversions, so we analysed existing HARPS spectra in order to calculate log R'HK for WASP-24 and thus determine whether or not the star is chromospherically active. We also observed a transit of WASP-24b in the Str\"{o}mgren u and y bands, with the CAHA 2.2-m telescope. Results. We measure occultation depths of 0.159 \pm 0.013 per cent at 3.6 {\mu}m and 0.202 \pm 0.018 per cent at 4.5 {\mu}m. The corresponding planetary brightness temperatures are 1974 \pm 71 K and 1944 \pm 85 K respectively. Atmosphere models with and without a thermal inversion fit the data equally well; we are unable to constrain the presence of an inversion without additional occultation measurements in the near-IR. We find log R'HK = -4.98 \pm 0.12, indicating that WASP-24 is not a chromospherically active star. Our global analysis of new and previously-published data has refined the system parameters, and we find no evidence that the orbit of WASP-24b is non-circular. Conclusions. These results emphasise the importance of complementing Spitzer measurements with observations at shorter wavelengths to gain a full understanding of hot Jupiter atmospheres., Comment: 7 pages, 4 figures, 3 tables. Accepted for publication in A&A

We report the discovery by the WASP transit survey of a giant planet in a close orbit (0.0295+-0.0009 AU) around a moderately bright (V=11.6, K=10) G9 dwarf (0.89+-0.08 M_sun, 0.84+-0.03 R_sun) in the Southern constellation Eridanus. Thanks to high-precision follow-up photometry and spectroscopy obtained by the telescopes TRAPPIST and Euler, the mass and size of this planet, WASP-50b, are well constrained to 1.47+-0.09 M_jup and 1.15+-0.05 R_jup, respectively. The transit ephemeris is 2455558.6120 (+-0.0002) + N x 1.955096 (+-0.000005) HJD_UTC. The size of the planet is consistent with basic models of irradiated giant planets. The chromospheric activity (log R'_HK = -4.67) and rotational period (P_rot = 16.3+-0.5 days) of the host star suggest an age of 0.8+-0.4 Gy that is discrepant with a stellar-evolution estimate based on the measured stellar parameters (rho_star = 1.48+-0.10 rho_sun, Teff = 5400+-100 K, [Fe/H]= -0.12+-0.08) which favours an age of 7+-3.5 Gy. This discrepancy could be explained by the tidal and magnetic influence of the planet on the star, in good agreement with the observations that stars hosting hot Jupiters tend to show faster rotation and magnetic activity (Pont 2009; Hartman 2010). We measure a stellar inclination of 84 (-31,+6) deg, disfavouring a high stellar obliquity. Thanks to its large irradiation and the relatively small size of its host star, WASP-50b is a good target for occultation spectrophotometry, making it able to constrain the relationship between hot Jupiters' atmospheric thermal profiles and the chromospheric activity of their host stars proposed by Knutson et al. (2010)., 9 pages, 8 figures. Accepted for publication in Astronomy & Astrophysics

We present SuperWASP observations of HAT-P-14b, a hot Jupiter discovered by Torres et al. The planet was found independently by the SuperWASP team and named WASP-27b after follow-up observations had secured the discovery, but prior to the publication by Torres et al. Our analysis of HAT-P-14/WASP-27 is in good agreement with the values found by Torres et al. and we refine the parameters by combining our datasets. We also provide additional evidence against astronomical false positives. Due to the brightness of the host star, V = 10, HAT-P-14 is an attractive candidate for further characterisation observations. The planet has a high impact parameter, b = 0.907 +/- 0.004, and the primary transit is close to grazing. This could readily reveal small deviations in the orbital parameters indicating the presence of a third body in the system, which may be causing the small but significant orbital eccentricity, e = 0.095 +/- 0.011. The system geometry suggests that the planet narrowly fails to undergo a secondary eclipse. However, even a non-detection would tightly constrain the system parameters.

Gravitational microlensing is not only a successful tool for discovering distant exoplanets, but it also enables characterization of the lens and source stars involved in the lensing event. In high magnification events, the lens caustic may cross over the source disk, which allows a determination of the angular size of the source and additionally a measurement of its limb darkening. When such extended-source effects appear close to maximum magnification, the resulting light curve differs from the characteristic Paczynski point-source curve. The exact shape of the light curve close to the peak depends on the limb darkening of the source. Dense photometric coverage permits measurement of the respective limb-darkening coefficients. In the case of microlensing event OGLE 2008-BLG-290, the K giant source star reached a peak magnification of about 100. Thirteen different telescopes have covered this event in eight different photometric bands. Subsequent light-curve analysis yielded measurements of linear limb-darkening coefficients of the source in six photometric bands. The best-measured coefficients lead to an estimate of the source effective temperature of about 4700 +100-200 K. However, the photometric estimate from colour-magnitude diagrams favours a cooler temperature of 4200 +-100 K. As the limb-darkening measurements, at least in the CTIO/SMARTS2 V and I bands, are among the most accurate obtained, the above disagreement needs to be understood. A solution is proposed, which may apply to previous events where such a discrepancy also appeared., Astronomy & Astrophysics in press

We report the discovery of a low-density exoplanet transiting an 11th magnitude star in the Southern hemisphere. WASP-15b, which orbits its host star with a period P=3.7520656+-0.0000028d has a mass M_p=0.542+-0.050M_J and radius R_p=1.428+-0.077R_J, and is therefore the one of least dense transiting exoplanets so far discovered (rho_p=0.247+-0.035g cm^-3). An analysis of the spectrum of the host star shows it to be of spectral type around F5, with an effective temperature T_eff=6300+-100K and [Fe/H]=-0.17+-0.11., Submitted to AJ

International audience; We report on the discovery of WASP-12b, a new transiting extrasolar planet with R pl = 1.79+0.09 -0.09 RJ and M pl = 1.41+0.10 -0.10 M J. The planet and host star properties were derived from a Monte Carlo Markov Chain analysis of the transit photometry and radial velocity data. Furthermore, by comparing the stellar spectrum with theoretical spectra and stellar evolution models, we determined that the host star is a supersolar metallicity ([M/H] = 0.3+0.05 -0.15), late-F (T eff = 6300+200 -100 K) star which is evolving off the zero-age main sequence. The planet has an equilibrium temperature of T eq = 2516 K caused by its very short period orbit (P = 1.09 days) around the hot, twelfth magnitude host star. WASP-12b has the largest radius of any transiting planet yet detected. It is also the most heavily irradiated and the shortest period planet in the literature.

We present high-precision photometry of two transit events of the extrasolar planetary system WASP-5, obtained with the Danish 1.54m telescope at ESO La Silla. In order to minimise both random and flat-fielding errors, we defocussed the telescope so its point spread function approximated an annulus of diameter 40 pixels (16 arcsec). Data reduction was undertaken using standard aperture photometry plus an algorithm for optimally combining the ensemble of comparison stars. The resulting light curves have point-to-point scatters of 0.50 mmag for the first transit and 0.59 mmag for the second. We construct detailed signal to noise calculations for defocussed photometry, and apply them to our observations. We model the light curves with the JKTEBOP code and combine the results with tabulated predictions from theoretical stellar evolutionary models to derive the physical properties of the WASP-5 system. We find that the planet has a mass of M_b = 1.637 +/- 0.075 +/- 0.033 Mjup, a radius of R_b = 1.171 +/- 0.056 +/- 0.012 Rjup, a large surface gravity of g_b = 29.6 +/- 2.8 m/s2 and a density of rho_b = 1.02 +/- 0.14 +/- 0.01 rhojup (statistical and systematic uncertainties). The planet's high equilibrium temperature of T_eq = 1732 +/- 80 K makes it a good candidate for detecting secondary eclipses., Comment: Accepted for publication in MNRAS. 9 pages, 4 figures, quite a few tables

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 1.846834+-0.000002 days. 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 finding it to have Teff = 6400+-100 K 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 M_J and radius 1.31 +0.07-0.14 R_J 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., 10 pages, 7 figures, 4 tables, submitted for publication in MNRAS

We report the discovery of a sub-Jupiter mass exoplanet transiting a magnitude V=11.7 host star 1SWASP J030928.54+304024.7. A simultaneous fit to the transit photometry and radial-velocity measurements yield a planet mass M_p=0.53+-0.07M_J, radius R_p=0.91^{+0.06}_{-0.03}R_J and an orbital period of 3.722465^{+0.000006}_{-0.000008} days. The host star is of spectral type K3V, with a spectral analysis yielding an effective temperature of 4800+-100K and log g=4.45+-0.2. It is amongst the smallest, least massive and lowest luminosity stars known to harbour a transiting exoplanet. WASP-11b is the third least strongly irradiated transiting exoplanet discovered to date, experiencing an incident flux F_p=1.9x10^8 erg s^{-1} cm^{-2} and having an equilibrium temperature T_eq=960+-70K., Comment: Submitted to A&A on 17-Sep-2008

The Wide Angle Search for Planets (WASP) photometrically surveys a large number of nearby stars to uncover candidate extrasolar planet systems by virtue of smallamplitude lightcurve dips on a . 5-day timescale typical of the \Hot-Jupiters." Observations with the SuperWASP-North instrument between April and September 2004 produced a rich photometric dataset of some 1.3£10 9 datapoints from 6.7 million stars. Our custom-built data acquisition and processing system produces » 0:02 mag photometric precision at V =13. We present the transit-candidates in the 03h-06h RA range. Of 141,895 lightcurves with su‐cient sampling to provide adequate coverage, 2688 show statistically significant transit-like periodicities. Of these, 44 pass visual inspection of the lightcurve, of which 24 are removed through a set of cuts on the statistical signiflcance of artefacts. All but 4 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 brie∞y the impact of sampling on our results.

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.

We present optical lightcurves of 428 periodic variable stars coincident with ROSAT X-ray sources, detected using the first run of the SuperWASP photometric survey. Only 68 of these were previously recognised as periodic variables. A further 30 of these objects are previously known pre-main sequence stars, for which we detect a modulation period for the first time. Amongst the newly identified periodic variables, many appear to be close eclipsing binaries, their X-ray emission is presumably the result of RS CVn type behaviour. Others are probably BY Dra stars, pre-main sequence stars and other rapid rotators displaying enhanced coronal activity. A number of previously catalogued pulsating variables (RR Lyr stars and Cepheids) coincident with X-ray sources are also seen, but we show that these are likely to be misclassifications. We identify four objects which are probable low mass eclipsing binary stars, based on their very red colour and light curve morphology., Comment: Accepted for publication in Astronomy & Astrophysics. This submission does not include Figure 1 (lightcurves & power spectra). The 107 panels of Figure 1 can be found online at http://physics.open.ac.uk/~ajnorton/wasp_rosat/

We present light curves and periods of 53 candidates for short period eclipsing binary stars identified by SuperWASP. These include 48 newly identified objects with periods, 5 pages of text, 18 pages of figures, 1 table. Accepted for publication in A&A. (Slight formatting modifications to previous uploaded version)

Photometric transit surveys promise to complement the currently known sample of extra-solar planets by providing additional information on the planets and especially their radii. Here we present extra-solar planet (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 April to October 2004 observing season. The data cover fields between 23hr and 03hr in RA at declinations above +12. This amounts to over $\approx$400,000 stars with V magnitudes 8 to 13.5. For the stars brighter than 12.5, we achieve better than 1 percent photometric precision. Here we present 41 sources with low amplitude variability between $\approx$ 1 and 10 mmag, from which we select 12 with periods between 1.2 and 4.4 days as the most promising extrasolar planet 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.

A unique shear stress-shear rate relationship exists for laminar flow of any time independent substance in a tube, whereas this is not the case for turbulent flow. In order to obtain a unique relationship for turbulent flow, a new approach based on the elementary theoretical interpretation of experimental data is adopted in the present paper. In particular, wall shear stress is found to be a unique function of a new turbulent pseudo shear rate term. In this relationship there are two parameters which characterize a given substance — the limiting viscosity at high shear rateµ m and a factorα m which takes into account modification of turbulent structure by the non-Newtonian properties. Both of these parameters must be determined experimentally. Methods of predicting pressure gradients and of scaling up are outlined. In applying the approach to suspensions in which the solid phase has a density greater than that of the liquid medium, it may be important to determine the increment in shear stress equivalent to the energy required to maintain the solid particles in suspension. The validity of this approach is confirmed by data for the flow of a variety of substances including kaolin suspensions and Carbopol solutions in tubes ranging in diameter from 1.5 to 20 mm.

Crystals of the title compound are monoclinic with a= 15·199, b= 23·814, c= 13·383 A, β= 119·07°, Z= 4 space group P21/m. 7113 visually estimated intensities were used, and the structure refined to R 9·83%. There are two crystallographically independent cations each possessing a mirror plane. The iridium atoms are at the centre of a trigonal bipyramid with the PPh3 ligands at the apices and the CO and CS groups co-planar with the iridium atoms in the equatorial plane. Mean thiocarbonyl bonding parameters are: Ir–C(S) 1·867, C–S 1·511 A; Ir–C–S = 178·2°. The σ and π bonding properties of the CO and CS groups are compared.

SummaryThe use of lanthanum hydroxide tracers permitted the demonstration of two distinct types of alterations in the ultrastructural appearance of the glomerular basement membrane in aminonucleoside nephrosis. In some capillary loops an increase in the number and size of lanthanum aggregates were observed, in others portions of the basement membrane measuring in length 600-1000 A the entire thickness of the membrane appeared to be filled with tracer molecules. It is concluded that the lanthanum method is a useful approach for the demonstration of ultrastructural changes in the basement membrane in instances where the use of conventional electron microscopic techniques fail to do so.