A Possible Detection of Occultation by a Proto-planetary Clump in GM Cephei

GM Cep in the young (~ 4 Myr) open cluster Trumpler 37 has been known to be an abrupt variable and to have a circumstellar disk with very active accretion. Our monitoring observations in 2009–2011 revealed the star to show sporadic ?are events, each with brightening of . 0.5 mag lasting for days. These brightening events, associated with a color change toward the blue, should originate from an increased accretion activity. Moreover, the star also underwent a brightness drop of ~ 1 mag lasting for about a month, during which the star became bluer when fainter. Such brightness drops seem to have a recurrence time scale of a year, as evidenced in our data and the photometric behavior of GM Cep over a century. Between consecutive drops, the star brightened gradually by about 1 mag and became blue at peak luminosity. We propose that the drop is caused by obscuration of the central star by an orbiting dust concentration. The UX Orionis type of activity in GM Cep therefore exemplifies the disk inhomogeneity process in transition between grain coagulation and planetesimal formation in a young circumstellar disk

Chromospherically Active Stars IX HD 33798 = V390 Aurigae: A Lithium-Rich Rapidly Rotating Single Giant

HD 33798 is a chromospherically active, rapidly rotating, lithium-rich, late-type giant. Analysis of 40 radial velocities indicates no periodic velocity variations, suggesting that the star is single, so its rapid rotation (v sin i = 29 km s-1) is highly unusual. Such rotation is inconsistent with the rotational brake hypothesis of Gray [ApJ, 262, 682 (1982); 347, 1021 (1989)] and the results of Rutten & Pylyser [A&A, 191, 227 (1988)]. Although there are many similarities to the supposed pre-main-sequence star HDE 283572, the lithium abundance and space motion of HD 33798 appears to be in a post-main-sequence phase of evolution, but its previous evolutionary history is uncertain. Its space motion is similar to FK Com, suggesting that it is a coalesced binary in the process of spinning down. However, if that is so, its large lithium abundance needs to be explained. A scenario in which the star was a rapidly rotating late B or early A star that has recently crossed the H-R gap and become a convective late-type giant could explain the large lithium abundance but is inconsistent with the space velocity components. A third scenario in which material is transferred from a rapidly rotating core may be the most likely

Observations of Shadow Bands at the Total Solar Eclipse of 16 February 1980

Photoelectric observations of short term light variations (shadow bands) at the 16 Feb. 1980 total solar eclipse have been made using a set of spatially separated PIN diodes. Light variations in a bandpass of 1-500 Hz were detected during the half-minutes preceding and following the total phase. Fourier analysis of the noise spectrum of the variations reveals a sharp drop-off for frequencies about 50 Hz and an overall spectrum quite similar to previously reported power spectra of stellar scintillation. This is consistent with an atmospheric origin for the shadow bands. Cross-correlations between the detector outputs are low, suggesting a short persistence time for the turbulent elements causing the patterns

Voicing our concerns: Attempts at Decentring German Theatre and Performance Studies

The field of German Theatre and Performance Studies shows a lack of engagement with colonial history and questions of race. Its overwhelming whiteness manifests itself in a persistent ignorance of a decades-long tradition of works produced by women of colour, feminists, and Black, Indigenous and People of Colour (BIPOC) researchers and activists who have actively worked on decentring the discipline from a German-speaking context. This article, a critical conversation between four German theatre scholars, sets out to clarify what it means to decentre GTPS from a Western-centric focus and proposes some methodological solutions to achieve this goal. Through reflecting on our own educational experiences and the sharing of anecdotes from the classroom, we conclude that decentring means more than adding to the reading list, rather it entails a visceral, continuous unlearning of racist attitudes and methodologies and requires a careful positioning of teachers, students and researchers alike

Prospective Associations between Religiousness/Spirituality and Depression and Mediating Effects of Forgiveness in a Nationally Representative Sample of United States Adults

The present investigation examines the prospective associations of religiousness/spirituality with depression and the extent to which various dimensions of forgiveness act as mediating mechanisms of these associations. Data are from a nationally representative sample of United States adults who were first interviewed in 1998 and reinterviewed six months later. Measures of religiousness/spirituality, forgiveness, and various sociodemographics were collected. Depression was assessed using the Composite International Diagnostic Interview administered by trained interviewers. Results showed that religiousness/spirituality, forgiveness of oneself and others, and feeling forgiven by God were associated, both cross-sectionally and longitudinally, with depressive status. After controlling for initial depressive status, only forgiveness of oneself and others remained statistically significant predictors of depression. Path analyses revealed that religiousness/spirituality conveyed protective effects, prospectively, on depression by way of an indirect path through forgiveness of others but not forgiveness of oneself. Hence, forgiveness of others acts as a mechanism of the salutary effect of religiousness/spirituality, but forgiveness of oneself is an independent predictor. Conclusions regarding the continued development of this type of research and for the treatment of clients with depression are offered

Rotational Periods and Starspot Activity of Young Solar-Type Dwarfs in the Open Cluster IC 4665

We present the results of a V-band photometric monitoring survey of 15 late-type dwarfs in the young open cluster IC 4665. Low-amplitude periodic light variations are found for 8 stars and ascribed to the modulation by starspots that cover typically a few percent of the stellar disk. Periods range from 0.6 to 3.7d, translating to equatorial velocities between 13 and 93 km.s-1. That no period longer than 4d was detected suggests a relative paucity of extremely slow rotators (Veq \u3c\u3c 10 km.s-1) among late-type dwarfs in IC 4665. The fractional number of slow rotators in IC 4665 is similar to that of Alpha Per cluster, suggesting that IC 4665 is close in age to Alpha Per (~50 Myr)

Superparticle Method for Simulating Collisions

For problems in astrophysics, planetary science and beyond, numerical simulations are often limited to simulating fewer particles than in the real system. To model collisions, the simulated particles (aka superparticles) need to be inflated to represent a collectively large collisional cross section of real particles. Here we develop a superparticle-based method that replicates the kinetic energy loss during real-world collisions, implement it in an $N$-body code and test it. The tests provide interesting insights into dynamics of self gravitating collisional systems. They show how particle systems evolve over several free fall timescales to form central concentrations and equilibrated outer shells. The superparticle method can be extended to account for the accretional growth of objects during inelastic mergers.Comment: accepted in Ap