67 research outputs found

    Employer Brand Opens up for a Gender Process Model

    Get PDF
    Regardless of a long tradition of legislation, policymaking and practical achievements, the issues ofgender equality and of the segregated labor market still remain a matter of concern in Sweden. Thispaper describes a collaborative process between a research project and an engineering enterprise.It describes the point of departure, based on the concept of employer brand, of a long-term changeprocess and the different phases and activities during an intensive period 2009. The collaborationaimed to develop innovative methods, and to apply them in order to achieve increased genderawareness, and thereby to be able to retain and attract the best labor for tomorrow. Differentapproaches and methods as analogies, anecdotes, and pictures were used to nourish the process.Findings showed that the interactive process contributed to increased awareness. During the processthe enterprise became more conscious of the potential of being a gender equal employe

    DAL and MAL - two projects to improve distance learning in the technical field in Sweden

    Get PDF
    One of the cornerstones of modern technological society is a well educated public. One way of achieving this is to emphasize distance learning and Life Long Learning (LLL). Swedish universities and colleges with engineering programs are aware of this demand and have started a cooperation to remedy the situation. A LLL-project was formed with participants from all universities and colleges with science and engineering programs. Funding of more than 100 000 Euro was obtained from the Swedish Knowledge Foundation (KK-stiftelsen). The first phase of the project is now finished and a second is planned. The project group met regularly and discussed common problems. Pedagogical platforms for distance learning (WebCT, LUVIT and FirstClass) were studied and tested. Existing distance education courses developed in Sweden and internationally were catalogued. The idea of a computerised system for merit portfolios was also developed. Three pilot projects were financed. New distance learning courses were developed and used in more than one university: • a digital signal processor (DSP-lab9) was constructed to be used in computer based laboratory work; • a course in data communication to be used for professional development of technical media personnel; and • a course in automation in production

    Migrating Birds and Tickborne Encephalitis Virus

    Get PDF
    During spring and autumn 2001, we screened 13,260 migrating birds at Ottenby Bird Observatory, Sweden, and found 3.4% were infested with ticks. Four birds, each a different passerine species, carried tickborne encephalitis virus (TBEV)–infected ticks (Ixodes ricinus). Migrating birds may play a role in the geographic dispersal of TBEV-infected ticks

    Kepler-93b: A Terrestrial World Measured to within 120 km, and a Test Case for a New Spitzer Observing Mode

    Get PDF
    We present the characterization of the Kepler-93 exoplanetary system, based on three years of photometry gathered by the Kepler spacecraft. The duration and cadence of the Kepler observations, in tandem with the brightness of the star, enable unusually precise constraints on both the planet and its host. We conduct an asteroseismic analysis of the Kepler photometry and conclude that the star has an average density of 1.652+/-0.006 g/cm^3. Its mass of 0.911+/-0.033 M_Sun renders it one of the lowest-mass subjects of asteroseismic study. An analysis of the transit signature produced by the planet Kepler-93b, which appears with a period of 4.72673978+/-9.7x10^-7 days, returns a consistent but less precise measurement of the stellar density, 1.72+0.02-0.28 g/cm^3. The agreement of these two values lends credence to the planetary interpretation of the transit signal. The achromatic transit depth, as compared between Kepler and the Spitzer Space Telescope, supports the same conclusion. We observed seven transits of Kepler-93b with Spitzer, three of which we conducted in a new observing mode. The pointing strategy we employed to gather this subset of observations halved our uncertainty on the transit radius ratio R_p/R_star. We find, after folding together the stellar radius measurement of 0.919+/-0.011 R_Sun with the transit depth, a best-fit value for the planetary radius of 1.481+/-0.019 R_Earth. The uncertainty of 120 km on our measurement of the planet's size currently renders it one of the most precisely measured planetary radii outside of the Solar System. Together with the radius, the planetary mass of 3.8+/-1.5 M_Earth corresponds to a rocky density of 6.3+/-2.6 g/cm^3. After applying a prior on the plausible maximum densities of similarly-sized worlds between 1--1.5 R_Earth, we find that Kepler-93b possesses an average density within this group.Comment: 20 pages, 9 figures, accepted for publication in Ap

    Kepler-68: Three Planets, One With a Density Between That of Earth and Ice Giants

    Full text link
    NASA's Kepler Mission has revealed two transiting planets orbiting Kepler-68. Follow-up Doppler measurements have established the mass of the innermost planet and revealed a third jovian-mass planet orbiting beyond the two transiting planets. Kepler-68b, in a 5.4 day orbit has mass 8.3 +/- 2.3 Earth, radius 2.31 +/- 0.07 Earth radii, and a density of 3.32 +/- 0.92 (cgs), giving Kepler-68b a density intermediate between that of the ice giants and Earth. Kepler-68c is Earth-sized with a radius of 0.953 Earth and transits on a 9.6 day orbit; validation of Kepler-68c posed unique challenges. Kepler-68d has an orbital period of 580 +/- 15 days and minimum mass of Msin(i) = 0.947 Jupiter. Power spectra of the Kepler photometry at 1-minute cadence exhibit a rich and strong set of asteroseismic pulsation modes enabling detailed analysis of the stellar interior. Spectroscopy of the star coupled with asteroseismic modeling of the multiple pulsation modes yield precise measurements of stellar properties, notably Teff = 5793 +/- 74 K, M = 1.079 +/- 0.051 Msun, R = 1.243 +/- 0.019 Rsun, and density 0.7903 +/- 0.0054 (cgs), all measured with fractional uncertainties of only a few percent. Models of Kepler-68b suggest it is likely composed of rock and water, or has a H and He envelope to yield its density of about 3 (cgs).Comment: 32 pages, 13 figures, Accepted to Ap

    Kepler-432: a red giant interacting with one of its two long period giant planets

    Get PDF
    We report the discovery of Kepler-432b, a giant planet (Mb=5.410.18+0.32MJup,Rb=1.1450.039+0.036RJupM_b = 5.41^{+0.32}_{-0.18} M_{\rm Jup}, R_b = 1.145^{+0.036}_{-0.039} R_{\rm Jup}) transiting an evolved star (M=1.320.07+0.10M,R=4.060.08+0.12R)(M_\star = 1.32^{+0.10}_{-0.07} M_\odot, R_\star = 4.06^{+0.12}_{-0.08} R_\odot) with an orbital period of Pb=52.5011290.000053+0.000067P_b = 52.501129^{+0.000067}_{-0.000053} days. Radial velocities (RVs) reveal that Kepler-432b orbits its parent star with an eccentricity of e=0.51340.0089+0.0098e = 0.5134^{+0.0098}_{-0.0089}, which we also measure independently with asterodensity profiling (AP; e=0.5070.114+0.039e=0.507^{+0.039}_{-0.114}), thereby confirming the validity of AP on this particular evolved star. The well-determined planetary properties and unusually large mass also make this planet an important benchmark for theoretical models of super-Jupiter formation. Long-term RV monitoring detected the presence of a non-transiting outer planet (Kepler-432c; Mcsinic=2.430.24+0.22MJup,Pc=406.22.5+3.9M_c \sin{i_c} = 2.43^{+0.22}_{-0.24} M_{\rm Jup}, P_c = 406.2^{+3.9}_{-2.5} days), and adaptive optics imaging revealed a nearby (0\farcs87), faint companion (Kepler-432B) that is a physically bound M dwarf. The host star exhibits high signal-to-noise asteroseismic oscillations, which enable precise measurements of the stellar mass, radius and age. Analysis of the rotational splitting of the oscillation modes additionally reveals the stellar spin axis to be nearly edge-on, which suggests that the stellar spin is likely well-aligned with the orbit of the transiting planet. Despite its long period, the obliquity of the 52.5-day orbit may have been shaped by star-planet interaction in a manner similar to hot Jupiter systems, and we present observational and theoretical evidence to support this scenario. Finally, as a short-period outlier among giant planets orbiting giant stars, study of Kepler-432b may help explain the distribution of massive planets orbiting giant stars interior to 1 AU.Comment: 22 pages, 19 figures, 5 tables. Accepted to ApJ on Jan 24, 2015 (submitted Nov 11, 2014). Updated with minor changes to match published versio

    Fundamental Properties of Kepler Planet-Candidate Host Stars using Asteroseismology

    Get PDF
    We have used asteroseismology to determine fundamental properties for 66 Kepler planet-candidate host stars, with typical uncertainties of 3% and 7% in radius and mass, respectively. The results include new asteroseismic solutions for four host stars with confirmed planets (Kepler-4, Kepler-14, Kepler-23 and Kepler-25) and increase the total number of Kepler host stars with asteroseismic solutions to 77. A comparison with stellar properties in the planet-candidate catalog by Batalha et al. shows that radii for subgiants and giants obtained from spectroscopic follow-up are systematically too low by up to a factor of 1.5, while the properties for unevolved stars are in good agreement. We furthermore apply asteroseismology to confirm that a large majority of cool main-sequence hosts are indeed dwarfs and not misclassified giants. Using the revised stellar properties, we recalculate the radii for 107 planet candidates in our sample, and comment on candidates for which the radii change from a previously giant-planet/brown-dwarf/stellar regime to a sub-Jupiter size, or vice versa. A comparison of stellar densities from asteroseismology with densities derived from transit models in Batalha et al. assuming circular orbits shows significant disagreement for more than half of the sample due to systematics in the modeled impact parameters, or due to planet candidates which may be in eccentric orbits. Finally, we investigate tentative correlations between host-star masses and planet candidate radii, orbital periods, and multiplicity, but caution that these results may be influenced by the small sample size and detection biases.Comment: 19 pages, 10 figures, 4 tables; accepted for publication in ApJ; machine-readable versions of tables 1-3 are available as ancillary files or in the source code; v2: minor changes to match published versio

    Stellar Spin-Orbit Misalignment in a Multiplanet System

    Full text link
    Stars hosting hot Jupiters are often observed to have high obliquities, whereas stars with multiple co-planar planets have been seen to have low obliquities. This has been interpreted as evidence that hot-Jupiter formation is linked to dynamical disruption, as opposed to planet migration through a protoplanetary disk. We used asteroseismology to measure a large obliquity for Kepler-56, a red giant star hosting two transiting co-planar planets. These observations show that spin-orbit misalignments are not confined to hot-Jupiter systems. Misalignments in a broader class of systems had been predicted as a consequence of torques from wide-orbiting companions, and indeed radial-velocity measurements revealed a third companion in a wide orbit in the Kepler-56 system.Comment: Accepted for publication in Science, published online on October 17 2013; PDF includes main article and supplementary materials (65 pages, 27 figures, 7 tables); v2: small correction to author lis

    Low-amplitude solar-like oscillations in the K5 V star ε\varepsilon Indi A

    Full text link
    We have detected solar-like oscillations in the mid K-dwarf ε\varepsilon Indi A, making it the coolest dwarf to have measured oscillations. The star is noteworthy for harboring a pair of brown dwarf companions and a Jupiter-type planet. We observed ε\varepsilon Indi A during two radial velocity campaigns, using the high-resolution spectrographs HARPS (2011) and UVES (2021). Weighting the time series, we computed the power spectra and established the detection of solar-like oscillations with a power excess located at 5265±110 μ5265 \pm 110 \ \muHz -- the highest frequency solar-like oscillations so far measured in any star. The measurement of the center of the power excess allows us to compute a stellar mass of 0.782±0.023 M0.782 \pm 0.023 \ M_\odot based on scaling relations and a known radius from interferometry. We also determine the amplitude of the peak power and note that there is a slight difference between the two observing campaigns, indicating a varying activity level. Overall, this work confirms that low-amplitude solar-like oscillations can be detected in mid-K type stars in radial velocity measurements obtained with high-precision spectrographs.Comment: 10 pages, 3 figures, accepted for publication in Ap

    Masses, radii, and orbits of small Kepler planets : The transition from gaseous to rocky planets

    Get PDF
    We report on the masses, sizes, and orbits of the planets orbiting 22 Kepler stars. There are 49 planet candidates around these stars, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars. Based on an analysis of the Kepler brightness measurements, along with high-resolution imaging and spectroscopy, Doppler spectroscopy, and (for 11 stars) asteroseismology, we establish low false-positive probabilities (FPPs) for all of the transiting planets (41 of 42 have an FPP under 1%), and we constrain their sizes and masses. Most of the transiting planets are smaller than three times the size of Earth. For 16 planets, the Doppler signal was securely detected, providing a direct measurement of the planet's mass. For the other 26 planets we provide either marginal mass measurements or upper limits to their masses and densities; in many cases we can rule out a rocky composition. We identify six planets with densities above 5 g cm-3, suggesting a mostly rocky interior for them. Indeed, the only planets that are compatible with a purely rocky composition are smaller than 2 R ⊕. Larger planets evidently contain a larger fraction of low-density material (H, He, and H2O).Peer reviewedFinal Accepted Versio
    corecore