Related papers: Ancient bronze disks, decorations and calendars
For several decades now, open clusters have been used to study the structure and chemical evolution of the disk of our Galaxy. Due to the fact that their ages and metallicities can be determined with relatively good precision, and since…
The Galactic disk retains a vast amount of information about how it came to be, and how it evolved over cosmic time. However, we know very little about the secular processes associated with disk evolution. One major uncertainty is the…
Since the discovery of the multi-ring structure of the HL Tau disk, ALMA data suggest that the dust continuum emission of many, if not all, protoplanetary disks consists of rings and gaps, no matter their spectral type or age. The origin of…
Transitional disks are protoplanetary disks with opacity gaps/cavities in their dust distribution, a feature that may be linked to planet formation. We perform Bayesian modeling of the three transitional disks SZ Cha, CS Cha and T25…
We agree with the interpretation of W. Schlosser, that the Nebra Sky Disc is a reminder of a method of determining a start date (and possibly also an end date) of the farming year. We extend this interpretation. We think that we found the…
The photometric and spectroscopic observational campaign organized for the 2008/9 eclipse of EE Cep revealed features, which indicate that the eclipsing disk in the EE Cep system has a multi-ring structure. We suggest that the gaps in the…
Precessing accretion discs have long been suggested as explanations for the long periods observed in a variety of X-ray binaries, most notably Her X-1/HZ Her. We show that an instability of the disc's response to the radiation reaction…
Transitional discs are a special type of protoplanetary discs where planet formation is thought to be taking place. These objects feature characteristic inner cavities and/or gaps of a few tens of AUs in the sub-millimitre images of the…
Circumstellar disks are the sites of planet formation, and the very high incidence of extrasolar planets implies that most of them actually form planetary systems. Studying the structure and evolution of protoplanetary disks can thus place…
Debris disks are optically thin, almost gas-free dusty disks observed around a significant fraction of main-sequence stars older than about 10 Myr. Since the circumstellar dust is short-lived, the very existence of these disks is considered…
We investigate ``shell structure'' from Babylonian times: periodicities and beats in computer-simulated lunar data corresponding to those observed by Babylonian scribes some 2500 years ago. We discuss the mathematical similarity between the…
Two decades ago "transitional disks" described spectral energy distributions (SEDs) of T Tauri stars with small near-IR excesses, but significant mid- and far-IR excesses. Many inferred this indicated dust-free holes in disks, possibly…
Debris disks are tenuous, dust-dominated disks commonly observed around stars over a wide range of ages. Those around main sequence stars are analogous to the Solar System's Kuiper Belt and Zodiacal light. The dust in debris disks is…
An "upward-driven disk" is a novel mechanical device built from LEGO parts. A circular disk is suspended from the point where it is sandwiched between two wheels, making it free to oscillate as a pendulum, but the location of that…
In this paper I propose a possible use of Roman Dodecahedra, which are bronze artifacts of gallo-roman origin dating from the 2nd or 3rd centuries AD, for playing a bowling game. The presence of holes and knobs can be quite important during…
Chondrule formation remains one of the most elusive early Solar System events. Here, we take the novel approach of employing numerical simulations to investigate chondrule origin beyond purely cosmochemical methods. We model the transport…
An intriguing correspondence between certain finite planar tessellations and the Descartes circle arrangements is presented. This correspondence may be viewed as a visualization of the spinor structure underlying Descartes circles.
Several observatories around the globe started regular full-disc imaging of the solar atmosphere in the Ca II K line in the early decades of the 20th century. These observations are continued today at a few sites with either old…
Numerous protoplanetary disks exhibit shadows in scattered light observations. These shadows are typically cast by misaligned inner disks and are associated with observable structures in the outer disk such as bright arcs and spirals.…
Recent observations have begun probing the early phases of disc formation, but little data yet exists on disc structure and morphology of Class 0 objects. Using simulations, we are able to lay out predictions of disc morphologies expected…