The GTC exoplanet transit spectroscopy survey. VII. Detection of sodium in WASP-52b's cloudy atmosphere

We report the first detection of sodium absorption in the atmosphere of the hot Jupiter WASP-52b. We observed one transit of WASP-52b with the low-resolution Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) at the 10.4 m Gran Telescopio Canarias (GTC). The resulting transmission spectrum, covering the wavelength range from 522 nm to 903 nm, is flat and featureless, except for the significant narrow absorption signature at the sodium doublet, which can be explained by an atmosphere in solar composition with clouds at 1 mbar. A cloud-free atmosphere is stringently ruled out. By assessing the absorption depths of sodium in various bin widths, we find that temperature increases towards lower atmospheric pressure levels, with a positive temperature gradient of 0.88 +/- 0.65 K/km, possibly indicative of upper atmospheric heating and a temperature inversion.Comment: 6 pages, 5 figures, accepted for publication in A&A Lette

The GTC exoplanet transit spectroscopy survey. VII. An optical transmission spectrum of WASP-48b

We obtained long-slit optical spectroscopy of one transit of WASP-48b with the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) spectrograph at the 10.4 m Gran Telescopio Canarias (GTC). We integrated the spectrum of WASP-48 and one reference star in several channels with different wavelength ranges, creating numerous color light curves of the transit. We fit analytic transit curves to the data taking into account the systematic effects present in the time series in an effort to measure the change of the planet-to-star radius ratio ($R_p/R_s$) across wavelength. After removing the transit model and systematic trends to the curves we reached precisions between 261 ppm and 455-755 ppm for the white and spectroscopic light curves, respectively. We obtained $R_p/R_s$ uncertainty values between $0.8 \times 10^{-3}$ and $1.5\times 10^{-3}$ for all the curves analyzed in this work. The measured transit depth for the curves made by integrating the wavelength range between 530 nm and 905 nm is in agreement with previous studies. We report a relatively flat transmission spectrum for WASP-48b with no statistical significant detection of atmospheric species, although the theoretical models that fit the data more closely include of TiO and VO.Comment: 8 pages, 8 figures. Accepted for publication in Astronomy and Astrophysic

Confirmation of an exoplanet using the transit color signature: Kepler-418b, a blended giant planet in a multiplanet system

We announce confirmation of Kepler-418b, one of two proposed planets in this system. This is the first confirmation of an exoplanet based primarily on the transit color signature technique. We used the Kepler public data archive combined with multicolor photometry from the Gran Telescopio de Canarias and radial velocity follow-up using FIES at the Nordic Optical Telescope for confirmation. We report a confident detection of a transit color signature that can only be explained by a compact occulting body, entirely ruling out a contaminating eclipsing binary, a hierarchical triple, or a grazing eclipsing binary. Those findings are corroborated by our radial velocity measurements, which put an upper limit of ~1 Mjup on the mass of Kepler-418b. We also report that the host star is significantly blended, confirming the ~10% light contamination suspected from the crowding metric in the Kepler light curve measured by the Kepler team. We report detection of an unresolved light source that contributes an additional ~40% to the target star, which would not have been detected without multicolor photometric analysis. The resulting planet-star radius ratio is 0.110 +/- 0.0025, more than 25% more than the 0.087 measured by Kepler, leading to a radius of 1.20 +/- 0.16 Rjup instead of the 0.94 Rjup measured by the Kepler team. This is the first confirmation of an exoplanet candidate based primarily on the transit color signature, demonstrating that this technique is viable from ground for giant planets. It is particularly useful for planets with long periods such as Kepler-418b, which tend to have long transit durations. Additionally, multicolor photometric analysis of transits can reveal unknown stellar neighbors and binary companions that do not affect the classification of the transiting object but can have a very significant effect on the perceived planetary radius.Comment: accepted by Astronomy & Astrophysic

The GTC exoplanet transit spectroscopy survey. VI. A spectrally-resolved Rayleigh scattering slope in GJ 3470b

Aims. As a sub-Uranus-mass low-density planet, GJ 3470b has been found to show a flat featureless transmission spectrum in the infrared and a tentative Rayleigh scattering slope in the optical. We conducted an optical transmission spectroscopy project to assess the impacts of stellar activity and to determine whether or not GJ 3470b hosts a hydrogen-rich gas envelop. Methods. We observed three transits with the low-resolution OSIRIS spectrograph at the 10.4 m Gran Telescopio Canarias, and one transit with the high-resolution UVES spectrograph at the 8.2 m Very Large Telescope. Results. From the high-resolution data, we find that the difference of the Ca II H+K lines in- and out-of-transit is only 0.67 +/- 0.22%, and determine a magnetic filling factor of about 10-15%. From the low-resolution data, we present the first optical transmission spectrum in the 435-755 nm band, which shows a slope consistent with Rayleigh scattering. Conclusions. After exploring the potential impacts of stellar activity in our observations, we confirm that Rayleigh scattering in an extended hydrogen/helium atmosphere is currently the best explanation. Further high-precision observations that simultaneously cover optical and infrared bands are required to answer whether or not clouds and hazes exist at high-altitude.Comment: 12 pages, 11 figures, accepted for publication in A&

Lasten vertaissuhteiden vuorovaikutus:etnografinen tutkimus taidekasvattajan toiminnassa varhaiskasvatusryhmässä

Tiivistelmä. Oulun kaupungilla on toiminut taidekasvattajia vuodesta 2017 lähtien. Heidät on otettu päiväkoteihin henkilökohtaisten avustajien tilalle erityistä tukea tarvitsevien lasten tukitoimenpiteeksi varhaiskasvatuksen ryhmiin. Tutkimuksen konteksti muodostuu varhaiskasvatuksen ryhmästä, jossa toimii taidekasvattaja toteuttaen taidekasvatuksellista toimintaa. Taidekasvattajatoiminta noudattaa varhaiskasvatussuunnitelmaa, jossa korostuvat vuorovaikutus, kaverisuhteet ja aikuisten tuki näille suhteille. Oulun kaupunki on esittänyt toiveen tutkimuksesta taidekasvattajien toimimiin ryhmiin kohdistuen. Tämä tutkimus keskittyy tutkimaan yhtä varhaiskasvatuksen 3–5-vuotiaiden ryhmää, missä työskentelee taidekasvattaja. Ryhmässä on 23 lasta, joista kaksi on erityisen tuen tarpeen omaavia. Tutkimuksen tarkoituksena on kuvata tutkimusryhmän lasten välisten vertaissuhteiden vuorovaikutusta. Tutkimuskysymyksenä on: minkälaista vuorovaikutusta lasten vertaissuhteissa on 3–5-vuotiaiden taidekasvatukseen painottuvassa varhaiskasvatuksenryhmässä? Tutkimuksen teoreettisena viitekehyksenä käsitellään ensiksi lasten vertaissuhteita. Vertaisilla tarkoitetaan henkilöitä, jotka ovat lapsen kanssa samalla tasolla sosiaalisessa, emotionaalisessa tai kognitiivisessa kehityksessä. Vertaissuhteiden aikaisempi tutkimus on kohdistunut lähinnä erityislapsiin sekä vuorovaikutuksen loukkaaviin prosesseihin. Tutkimuksen toinen teoreettinen osio käsittelee vertaissuhteissa tapahtuvaa vuorovaikutusta. Vuorovaikutuksessa katseet, ilmeet, eleet, sanallinen kommunikaatio sekä sosiaaliset rakenteet näyttelevät tärkeää osaa lasten välisessä kommunikaatiossa. Hyväksyvä ja torjuva vuorovaikutus viittaavat siihen, kuinka hyvin lapsi pääsee mukaan vertaisryhmänsä toimintaan. Tutkimukseni on kvalitatiivinen tutkimus, jossa metodologisena viitekehyksenä käytetään etnografiaa. Etnografisessa tutkimuksessa tutkittavien elämä ja heidän kokemuksensa ovat keskeisiä tutkimuksen kohteita. Tutkimusaineistoni koostuu kenttämuistiinpanoista, lasten ryhmähaastatteluista sekä ryhmän taidekasvattajan ja varhaiskasvatuksen opettajan haastatteluista. Kenttäjakson havainnointi kohdistui pääosin taidekasvatukselliseen toimintaan mutta laajentui myöhemmin koskemaan myös vapaan leikin tilanteita. Aineiston tuoton jälkeen litteroin muistiinpanoni ja haastattelut. Litteroinnin jälkeen poimin aineistosta lasten väliset vuorovaikutukselliset tilanteet. Aineiston analyysin tein pitkälti aineistolähtöisesti. Tarkastelin erilaisia vuorovaikutuksen tapoja ja kategorisoin ne. Tulosten käsittelyä varten jaoin ne kolmeen eri teemaan: lasten vertaissuhteiden yleiset piirteet, vertaissuhteiden hyväksyvä vuorovaikutus ja vertaissuhteiden torjuva vuorovaikutus. Vertaissuhteiden yleisinä piirteinä nousi esiin tuloksina lasten ystävyyssuhteet, taidekasvatukseen suhtautuminen, leikki, lasten erilaiset roolit sekä erityistä tukea tarvitsevien lasten vuorovaikutus. Lasten välisessä hyväksyvässä vuorovaikutuksessa eniten nousi esille auttaminen ja kannustaminen, lasten keskeiset sanaleikit sekä jäljittely. Torjuvaa vuorovaikutusta lapset ilmaisivat kilpailun, vastakkaisen mielipiteen ilmaisun, kielteisten tunteiden ilmaisun sekä konfliktitilanteiden kautta

Happamilla sulfaattimailla sijaitsevien maatalousalueiden happamuuden hallintamenetelmät

Tiivistelmä. Työn tavoitteena oli perehtyä happamien sulfaattimaiden hallintamenetelmiin maatalousalueilla kirjallisuuskatsauksen avulla. Työssä pyrittiin selvittämään happamien sulfaattimaiden haittojen hallinta- ja ehkäisymenetelmien toimivuutta käymällä läpi teoriaa sekä toteutuneita pilot-hankkeita. Työn alussa käydään määritellen läpi happamien sulfaattimaiden muodostuminen ja vaikutukset ympäristöön sekä mitä edellytyksiä tehokas ja tuottoisa maatalouden peltoviljely vaatii maaperältä. Työn toisessa osassa keskitytään itse happamuuden haittojen ehkäisy- ja torjuntamenetelmiin, sekä kuinka ne soveltuvat toteutettaviksi peltoviljelyssä. Työn toisessa osassa on myös esitetty muutama käytännön tutkimus eri menetelmistä. Tuloksena todettiin, että vallitsevan alueen olosuhteet tulee tuntea, jotta voidaan valita käyttökelpoisin haittojen ehkäisy- tai torjuntakeino. Valintaan vaikuttavat maa-alueella olevan happaman sulfaattimaan etäisyys maanpinnasta, peltoalueen pinnanmuodot, ympäristön olosuhteet sekä pellolla olemassa oleva kuivatusmenetelmä. Monissa tehokkaimmissa happamien sulfaattimaiden ehkäisykeinoissa kustannukset nousevat usein rajoittavaksi tekijäksi, jolloin alueilla ei pystytä käyttämään parhaimpia menetelmiä. Pääasiassa pyritään ehkäisemään sulfidisedimentin happamoituminen ehkäisevillä keinoilla, kuten säätösalaojituksella, mutta joskus joudutaan lisäksi turvautumaan haittoja torjuviin keinoihin, kuten kalkitsemiseen. Niiden teho saattaa olla lyhytaikainen, jolloin alueen käsittely tulisi toistaa tietyn ajan kuluessa, mikä taas nostaa kustannuksia. Tulevaisuudessa tulisi tehdä enemmän pitkäkestoisia hankekokeiluja erilaisilla alueilla ja hallintamenetelmillä, jotta voitaisiin selvittää eri menetelmien tehokkuutta tuotannollisesti sekä kustannuksellisesti.Acidity management methods for agricultural areas in acid sulfate soils. Abstract. The aim of the work was to get familiarize with the control methods of acid sulfate soils in agricultural areas with the help of a literature review. This work aimed to find effective techniques to manage and prevent the disadvantages of acid sulfate soils by reviewing the theory and the implemented pilot projects. At the beginning of the work, acid sulfate soils formation and its effects to the environment were reviewed. And the condition of the soil to preserve efficient and profitable field cultivation. The second part of the work focuses on techniques to prevent and control the disadvantages of acidity and how they are suitable for implementation in arable farming. The second part of the thesis also presents a few practical studies of different methods. As a result, it was concluded that the conditions in the area should be known to be able to choose the right and best acidity control method. The choice is affected by the distance of the acid sulfate soil from the ground, topography, the environmental conditions, and the drying method existing in the field. In many of the most effective means of preventing acid sulfate soils, costs often become a limiting factor, making it impossible to use the best methods. The main aim is to prevent the acidification of sulfide clay using preventive measures as controlled drainage, but sometimes it is also necessary to control the effects of the harm as liming. Harm controls effectiveness may be short-lived, and that’s why treatment should be repeated over time, and it raises costs. In the future, more long-lasting project experiments with different ground areas and management methods should be researched to determine the efficiency of various techniques in terms of production and cost

Exhaust emissions of non-road mobile machine : Real-world and laboratory studies with diesel and HVO fuels

Exhaust emissions emitted by a non-road mobile machine were studied chasing a tractor in real-world conditions and repeating the same transient tests with a similar engine on an engine dynamometer where additionally, non-road steady state tests were carried out. The engines were equipped with an oxidation catalyst (DOC) and a selective catalytic reduction (SCR)system, and they were fuelled by fossil diesel fuel with ultra-low sulphur content and hydrotreated vegetable oil (HVO). By substituting diesel fuel with HVO the on-road emissions of nitrogen oxides (NOx) reduced 20% and particle number 44%, the emission factors being EFNOx =1.62 +/- 0.04 g/kWh and EFN = (28.2 +/- 7.8) x 10(13) #/kWh. Similar trend was observed for NOx at laboratory although the emissions were somewhat smaller than on-road. In contrast to real-world, in the laboratory experiment the EFN was only 2% smaller with HVO than with diesel, and these emission factors were almost one order of magnitude smaller than observed on-road. The number size distribution and volatility measurements showed that in real-world experiments small nucleation mode particles were formed during uphill and during downhill in engine braking conditions. These were not observed at laboratory. However, nucleation mode particles were observed in the laboratory experiments at high load steady driving conditions. At steady state tests the emissions strongly depended on engine load and engine speed with both fuels. (C) 2017 Elsevier Ltd. All rights reserved.Peer reviewe

A feature-rich transmission spectrum for WASP-127b

WASP-127b is one of the lowest density planets discovered to date. With a sub-Saturn mass ($M_{\rm p}=0.18 \pm 0.02 M_J$) and super-Jupiter radius ($R_{\rm p}= 1.37 \pm 0.04 R_J$), it orbits a bright G5 star, which is about to leave the main-sequence. We aim to explore WASP-127b's atmosphere in order to retrieve its main atmospheric components, and to find hints for its intriguing inflation and evolutionary history. We used the ALFOSC spectrograph at the NOT telescope to observe a low resolution ($R\sim330$, seeing limited) long-slit spectroscopic time series during a planetary transit, and present here the first transmission spectrum for WASP-127b. We find the presence of a strong Rayleigh slope at blue wavelengths and a hint of Na absorption, although the quality of the data does not allow us to claim a detection. At redder wavelengths the absorption features of TiO and VO are the best explanation to fit the data. Although higher signal-to-noise ratio observations are needed to conclusively confirm the absorption features, WASP-127b seems to posses a cloud-free atmosphere and is one of the best targets to perform further characterization studies in the near future.Comment: Accepted for Publication A&A Letters, May 22nd, 201

Featureless transmission spectra of 12 giant exoplanets observed by GTC/OSIRIS

Exoplanet atmospheres are the key to understanding the nature of exoplanets. To this end, transit spectrophotometry provides us opportunities to investigate the physical properties and chemical compositions of exoplanet atmospheres. We aim to detect potential atmospheric signatures in 12 gaseous giant exoplanets using transit spectrophotometry and we try to constrain their atmospheric properties. The targets of interest were observed using transit spectrophotometry with the GTC OSIRIS instrument. We estimated the transit parameters and obtained the optical transmission spectra of the target planets using a Bayesian framework. We analyzed the spectral features in the transmission spectra based on atmospheric retrievals. Most of the observed transmission spectra were found to be featureless, with only the spectrum of CoRoT-1b showing strong evidence for atmospheric features. However, in combination with the previously published near-infrared transmission spectrum, we found multiple interpretations for the atmosphere of CoRoT-1b due to the lack of decisive evidence for alkali metals or optical absorbers. Featureless spectra are not necessarily indicative of cloudy atmospheres if they poorly constrain the altitudes of cloud decks. Precise constraints on the models of hazes and clouds strongly depend on the significance of the observed spectral features. Further investigations on these exoplanets, especially CoRoT-1b, are required to confirm the properties of their atmospheres.Comment: 29 pages, 16 figures, accepted for publication in A&

Stellar activity and rotation of the planet host Kepler-17 from long-term space-borne photometry

The study of young Sun-like stars is of fundamental importance to understand the magnetic activity and rotational evolution of the Sun. Space-borne photometry by the Kepler telescope provides unprecedented datasets to investigate these phenomena in Sun-like stars. We present a new analysis of the entire Kepler photometric time series of the moderately young Sun-like star Kepler-17 that is accompanied by a transiting hot Jupiter. We applied a maximum-entropy spot model to the long-cadence out-of-transit photometry of the target to derive maps of the starspot filling factor versus the longitude and the time. These maps are compared to the spots occulted during transits to validate our reconstruction and derive information on the latitudes of the starspots. We find two main active longitudes on the photosphere of Kepler-17, one of which has a lifetime of at least $\sim 1400$ days, although with a varying level of activity. The latitudinal differential rotation is of solar type, that is, with the equator rotating faster than the poles. We estimate a minimum relative amplitude $\Delta \Omega/ \Omega$ between $\sim 0.08 \pm 0.05$ and $0.14 \pm 0.05$, our determination being affected by the finite lifetime of individual starspots and depending on the adopted spot model parameters. We find marginal evidence of a short-term intermittent activity cycle of $\sim 48$ days and an indication of a longer cycle of $400-600$ days characterized by an equatorward migration of the mean latitude of the spots as in the Sun. The rotation of Kepler-17 is likely to be significantly affected by the tides raised by its massive close-by planet. We confirm the reliability of maximum-entropy spot models to map starspots in young active stars and characterize the activity and differential rotation of this young Sun-like planetary host.Comment: Accepted by Astronomy and Astrophysics - 22 pages, 29 figure, 1 table, 2 appendixe