analysing optical spectra of M dwarfs

Unter stellarer Aktivität werden eine Reihe von Phänomenen in den unterschiedlichen Atmosphärenschichten zusammengefasst, die eng mit dem Magnetfeld des einzelnen Sterns verbunden sind. Da eine direkte Auflösung der Sternoberfläche, wie uns dies bei der Sonne möglich ist, für aktive Sterne noch in ferner Zukunft liegt, können diese Phänomene im Normalfall nicht direkt beobachtet werden. Es können aber aus der Spektralanalyse indirekt Informationen über die Aktivität eines Sterns gewonnen werden. Die vorliegende Arbeit beschäftigt sich mit koronaler und chromosphärischer Aktivität von mittleren und späten M Sternen und deren Nachweis und Analyse in UVES Echelle-Spektren von 3030 bis 3880 und 4580 bis 6680 A. Dabei widmet sich der erste Teil der Arbeit dem Nachweis der verbotenen koronalen Fe XIII Linie bei 3388 A. Das mehrere Millionen Kelvin heiße koronale Gas wird normalerweise - und am leichtesten - im Röntgenbereich beobachtet...thesi

Random function tracer Patent

Design and development of random function tracer for obtaining coordinates of points on contour map

Kepler super-flare stars: what are they?

The Kepler mission has led to the serendipitous discovery of a significant number of `super flares' - white light flares with energies between 10^33 erg and 10^36 erg - on solar-type stars. It has been speculated that these could be `freak' events that might happen on the Sun, too. We have started a programme to study the nature of the stars on which these super flares have been observed. Here we present high-resolution spectroscopy of 11 of these stars and discuss our results. We find that several of these stars are very young, fast-rotating stars where high levels of stellar activity can be expected, but for some other stars we do not find a straightforward explanation for the occurrence of super flares.Comment: Accepted for publication in A&A, 9 pages, 4 figure

Experimental study of dynamic effects of crew motion in a Manned Orbital Research Laboratory /MORL/

Disturbance profiles of routine crew motion in simulated zero gravity environment of manned orbital research laborator

Multiwavelength observations of a giant flare on CN Leonis I. The chromosphere as seen in the optical spectra

Flares on dM stars contain plasmas at very different temperatures and thus affect a wide wavelength range in the electromagnetic spectrum. While the coronal properties of flares are studied best in X-rays, the chromosphere of the star is observed best in the optical and ultraviolet ranges. Therefore, multiwavelength observations are essential to study flare properties throughout the atmosphere of a star. We analysed simultaneous observations with UVES/VLT and XMM-Newton of the active M5.5 dwarf CN Leo (Gl 406) exhibiting a major flare. The optical data cover the wavelength range from 3000 to 10000 Angstrom. From our optical data, we find an enormous wealth of chromospheric emission lines occurring throughout the spectrum. We identify a total of 1143 emission lines, out of which 154 are located in the red arm, increasing the number of observed emission lines in this red wavelength range by about a factor of 10. Here we present an emission line list and a spectral atlas. We also find line asymmetries for H I, He I, and Ca II lines. For the last, this is the first observation of asymmetries due to a stellar flare. During the flare onset, there is additional flux found in the blue wing, while in the decay phase, additional flux is found in the red wing. We interpret both features as caused by mass motions. In addition to the lines, the flare manifests itself in the enhancement of the continuum throughout the whole spectrum, inverting the normal slope for the net flare spectrum.Comment: 15 pages, accepted by A&

Fortifying the Front Line: The Marcus Collaborative Coaching Project

As professionals in the area of child development, we share the common goal that every child is supported in obtaining his or her fullest developmental potential. This can be achieved by empowering our front-line caregivers and teachers with expert knowledge and skills via communication, internalization, and practice through collaborative learning experiences with other specialists in the field. Though each team member brings a specific level of knowledge and experience to collaboration, there are important processes that must occur to ensure all tools are consolidated into appropriate support of the utmost quality for each child. These include understanding the process of adult learning, reflection, and how to effectively communicate accordingly. As each team member develops and hones their skills, each is able to coach others: other specialists, professionals, teachers, and even parents, multiplying the number of children who receive the highest level of developmental support exponentially. An example of practical implementation is seen in the Marcus Autism Center / DECAL Collaborative Coaching Project, whose goal is to train front-line caregivers to identify red flags for Autism as early as possible, and developmentally support accordingly

PHOENIX model chromospheres of mid- to late-type M dwarfs

We present semi-empirical model chromospheres computed with the atmosphere code PHOENIX. The models are designed to fit the observed spectra of five mid- to late-type M dwarfs. Next to hydrogen lines from the Balmer series we used various metal lines, e. g. from Fe {\sc i}, for the comparison between data and models. Our computations show that an NLTE treatment of C, N, O impacts on the hydrogen line formation, while NLTE treatment of less abundant metals such as nickel influences the lines of the considered species itself. For our coolest models we investigated also the influence of dust on the chromospheres and found that dust increases the emission line flux. Moreover we present an (electronically published) emission line list for the spectral range of 3100 to 3900 and 4700 to 6800 \AA for a set of 21 M dwarfs and brown dwarfs. The line list includes the detection of the Na {\sc i} D lines in emission for a L3 dwarf.Comment: 14 pages, 18 figure