25 research outputs found
Hot Subdwarfs in Resolved Binaries
In the last decade or so, there have been numerous searches for hot subdwarfs
in close binaries. There has been little to no attention paid to wide binaries
however. The advantages of understanding these systems can be many. The stars
can be assumed to be coeval, which means they have common properties. The
distance and metallicity, for example, are both unknown for the subdwarf
component, but may be determinable for the secondary, allowing other properties
of the subdwarf to be estimated. With this in mind, we have started a search
for common proper motion pairs containing a hot subdwarf component. We have
uncovered several promising candidate systems, which are presented here.Comment: 6 pages, 4 figures. Proceedings of The Fourth Meeting on Hot Subdwarf
Stars and Related Objects held in China, 20-24 July 2009. Accepted for
publication in Astrophysics and Space Scienc
Exomoon simulations
We introduce and describe our newly developed code that simulates light
curves and radial velocity curves for arbitrary transiting exoplanets with a
satellite. The most important feature of the program is the calculation of
radial velocity curves and the Rossiter-McLaughlin effect in such systems. We
discuss the possibilities for detecting the exomoons taking the abilities of
Extremely Large Telescopes into account. We show that satellites may be
detected also by their RM effect in the future, probably using less accurate
measurements than promised by the current instrumental developments. Thus, RM
effect will be an important observational tool in the exploration of exomoons.Comment: 5 pages, 2 figures with 9 figure panels, accepted by EM&
Size Doesn't Matter: Towards a More Inclusive Philosophy of Biology
notes: As the primary author, O’Malley drafted the paper, and gathered and analysed data (scientific papers and talks). Conceptual analysis was conducted by both authors.publication-status: Publishedtypes: ArticlePhilosophers of biology, along with everyone else, generally perceive life to fall into two broad categories, the microbes and macrobes, and then pay most of their attention to the latter. ‘Macrobe’ is the word we propose for larger life forms, and we use it as part of an argument for microbial equality. We suggest that taking more notice of microbes – the dominant life form on the planet, both now and throughout evolutionary history – will transform some of the philosophy of biology’s standard ideas on ontology, evolution, taxonomy and biodiversity. We set out a number of recent developments in microbiology – including biofilm formation, chemotaxis, quorum sensing and gene transfer – that highlight microbial capacities for cooperation and communication and break down conventional thinking that microbes are solely or primarily single-celled organisms. These insights also bring new perspectives to the levels of selection debate, as well as to discussions of the evolution and nature of multicellularity, and to neo-Darwinian understandings of evolutionary mechanisms. We show how these revisions lead to further complications for microbial classification and the philosophies of systematics and biodiversity. Incorporating microbial insights into the philosophy of biology will challenge many of its assumptions, but also give greater scope and depth to its investigations
The Small GTP-binding Protein R-Ras Can Influence Integrin Activation by Antagonizing a Ras/Raf-initiated Integrin Suppression Pathway
Information-Theoretic Based Feature Selection for Multi-Voxel Pattern Analysis of fMRI Data
Hot subdwarfs in binary systems and the nature of their unseen companions
A large fraction of the sdB stars reside in short period binaries. It is therefore clear that binary evolution plays an important role in the still unsolved problem of hot subdwarf formation. Here we present new results from different projects devoted to the analysis of sdBs in close binaries. The nature and masses of the unseen companions of 31 sdBs have been constrained by an analysis of high resolution spectra. In the course of this study candidate systems with massive compact companions have been discovered. The HYPERMUCHFUSS project aims at finding such systems making use of the huge spectral database of SDSS. A multi-site follow-up campaign of promising radial velocity variable sdBs started in 2009 and preliminary results are shown here. The most recent discovery of a substellar companion to the bright sdB HD 149382 may provide new evidence for the decisive role of low mass companions for sdB formation in general. A mysterious IR-excess has been detected, which may be caused by this otherwise invisible companion. Another low mass companion has been found to orbit the sdB star EGB 5 within 16.5 days. The space mission CoRoT is performing wide field and high precision photometry. First preliminary results from a spectroscopic survey of the COROT fields are also reported