67 research outputs found
Employer Brand Opens up for a Gender Process Model
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
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
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
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
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
We report the discovery of Kepler-432b, a giant planet ()
transiting an evolved star with an orbital period of days. Radial velocities (RVs) reveal that
Kepler-432b orbits its parent star with an eccentricity of , which we also measure independently with
asterodensity profiling (AP; ), 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; 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
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
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 Indi A
We have detected solar-like oscillations in the mid K-dwarf
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 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 Hz
-- 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 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
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
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