How to Make a Singleton sdB Star via Accelerated Stellar Evolution

Many hot subdwarf B stars (sdBs) are in close binaries, and the favored formation channels for subdwarfs rely on mass transfer in a binary system to strip a core He burning star of its envelope. However, these channels cannot account for sdBs that have been observed in long period binaries nor the narrow mass distribution of isolated (or "singleton") sdBs. We propose a new formation channel involving the merger of a helium white dwarf and a low mass, hydrogen burning star, which addresses these issues. Hierarchical triples whose inner binaries merge and form sdBs by this process could explain the observed long period subdwarf+main sequence binaries. This process would also naturally explain the observed slow rotational speeds of singleton sdBs. We also briefly discuss the implications of this formation channel for extreme horizontal branch morphology in globular clusters and the UV upturn in elliptical galaxies.Comment: 5 pages, 3 figures, accepted for publication ApJ

MUCHFUSS - Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS

The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS) aims at finding hot subdwarf stars with massive compact companions (white dwarfs with masses $M>1.0 {\rm M_{\odot}}$, neutron stars or black holes). The existence of such systems is predicted by binary evolution calculations and some candidate systems have been found. We identified $\simeq1100$ hot subdwarf stars from the Sloan Digital Sky Survey (SDSS). Stars with high velocities have been reobserved and individual SDSS spectra have been analysed. About 70 radial velocity variable subdwarfs have been selected as good candidates for follow-up time resolved spectroscopy to derive orbital parameters and photometric follow-up to search for features like eclipses in the light curves. Up to now we found nine close binary sdBs with short orbital periods ranging from $\simeq0.07 {\rm d}$ to $1.5 {\rm d}$. Two of them are eclipsing binaries with companions that are most likely of substellar nature.Comment: 6 pages, 4 figures, AN, in pres

Novel shock absorber features varying yield strengths

A shock absorbent webbing of partially drawn synthetic strands is arranged in sections of varying density related to the varying mass of the human body. This is contoured to protect the body at points of contact, when subjected to large acceleration or deceleration forces

Moving Environments: Affect, Emotion, Ecology, and Film edited by Alexa Weik von Mossner

Ted Geier reviews Completely Affecting: The Cinematics of Environmental Concern and Real Change, edited by Alexa Weik von Mossner

Approximate solution to the stochastic Kuramoto model

We study Kuramoto phase oscillators with temporal fluctuations in the frequencies. The infinite-dimensional system can be reduced in a Gaussian approximation to two first-order differential equations. This yields a solution for the \emph{time-dependent} order parameter, which characterizes the synchronization between the oscillators. The known critical coupling strength is exactly recovered by the Gaussian theory. Extensive numerical experiments further show that the analytical results are very accurate below and sufficiently above the critical value. We obtain the asymptotic order parameter \emph{in closed form}, which suggests a tighter upper bound for the corresponding scaling. As a last point, we elaborate the Gaussian approximation in complex networks with distributed degrees.Comment: 6 pages, 3 figure

Organic grapes - More than Wine and Statistics

The chapter presents inforamtion on the status of organic viticulture world wide and also includes a global organic wine statistics (hectares per country; not all wine producing countries covered though)

Circumbinary Planets Orbiting the Rapidly Pulsating Subdwarf B-type binary NY Vir

We report here the tentative discovery of a Jovian planet in orbit around the rapidly pulsating subdwarf B-type (sdB-type) eclipsing binary NY Vir. By using new determined eclipse times together with those collected from the literature, we detect that the observed-calculated (O-C) curve of NY Vir shows a small-amplitude cyclic variation with a period of 7.9\,years and a semiamplitude of 6.1\,s, while it undergoes a downward parabolic change (revealing a period decrease at a rate of $\dot{P}=-9.2\times{10^{-12}}$). The periodic variation was analyzed for the light-travel time effect via the presence of a third body. The mass of the tertiary companion was determined to be $M_3\sin{i^{\prime}}=2.3(\pm0.3)$\,$M_{Jupiter}$ when a total mass of 0.60\,$M_{\odot}$ for NY Vir is adopted. This suggests that it is most probably a giant circumbinary planet orbiting NY Vir at a distance of about 3.3 astronomical units (AU). Since the rate of period decrease can not be explained by true angular momentum loss caused by gravitational radiation or/and magnetic braking, the observed downward parabolic change in the O-C diagram may be only a part of a long-period (longer than 15 years) cyclic variation, which may reveal the presence of another Jovian planet ($\sim2.5$$M_{Jupiter}$) in the system.Comment: 12 pages, 3 figures, accepted by ApJ Letter

Why do hot subdwarf stars pulsate?

Hot subdwarf B stars (sdBs) are the stripped cores of red giants located at the bluest extension of the horizontal branch. Several different kinds of pulsators are found among those stars. The mechanism that drives those pulsations is well known and the theoretically predicted instability regions for both the short-period p-mode and the long-period g-mode pulsators match the observed distributions fairly well. However, it remains unclear why only a fraction of the sdB stars pulsate, while stars with otherwise very similar parameters do not show pulsations. From an observers perspective I review possible candidates for the missing parameter that makes sdB stars pulsate or not.Comment: Astronomy in Focus, Volume 1, XXIXth IAU General Assembly, August 2015. P. Benvenuti, e

Born Naked by Farley Mowat

Farley Mowat\u27s charming childhood memoir covers the usual Mowat terrain: riotous humour, humble reverence, and a meticulous accounting of the little things that make life--all life--dear to us. Mowat\u27s work deserves regular attention in animal studies and environmental literary studies. His autobiographical techniques, as this review suggests, can be both assets and occasional impediments. But there is no replacing or replicating a Farley Mowat, and Born Naked deserves to be read immediately and repeatedly as one of the lasting legacies of a long life, well-lived