Introduction: Coronae are unique class of structures that were discovered during analysis of data from Venera-15/16 mission [1,2]. The defining element of coronae is their circular rim that consists of either ridges or grooves. In the images taken by Venera-15/16 (~1/4 of the surface of Venus), most of coronae appear to have ridged rim. After Magellan mission it became evident, however, that ri...

We present a systematic investigation of X-ray thermal coronae in 157 early-type galaxies and 22 late-type galaxies from a survey of 25 hot (kT > 3 keV), nearby (z < 0.05) clusters, based on Chandra archival data. Cool galactic coronae (kT = 0.5 1.1 keV generally) have been found to be very common, > 60% in NIR selected galaxies that are more luminous than 2 L∗, and > 40% in L∗ < LKs < 2 L∗ gal...

The details of stratigraphic units and structures making up six coronae and their regional surroundings on Venus were examined using full resolution Magellan images and stereoscopic coverage. Altimetry and stereoscopic coverage were essential in establishing the local stratigraphic relationships and the timing of corona-related topography. The degree of preservation of signatures of earlier cor...

Introduction: Coronae are quasi-circular to circular volcano-tectonic features unique to Venus among the terrestrial planets. They were first identified in Venera 15/16 images [1], and their tectonic, volcanic, and topographic characteristics have been classified in detail using Magellan SAR image and topography data [2, 3]. Several studies of gravity signatures associated with coronae have bee...

Introduction: Extensive mapping of the surface of Venus and continued analysis of Magellan data have allowed a more comprehensive survey of coronae to be conducted [1]. Our updated corona database contains 514 features, an increase from the 326 coronae of the previous survey [2]. We include a new set of 106 Type 2 or 'stealth' [3] coronae, which have a topog-raphic rather than a fracture annulu...

The existence of power law statistics in solar and stellar flares has prompted the suggestion that solar and stellar coronae are in a self-organized critical state, but the physical foundation of this theory is lacking. We present observational evidence from 107 flare events in 37 sun-like stars that solar and stellar coronae self-organize into a critical state set by a bifurcation in the dynam...

Introduction: Venus as a probable single-plate planet [1] has a unique set of volcano-tectonic features. The enigmatic circular structures, coronae are of great interest in particular. The corona definition does also include other concentric features known as the “arachnoids” [2], but it does not elaborate on the details of the concentric volcano-tectonic structures. In several cases, coronae a...

We prove some extension theorems for analytic objects, in particular sections of a coherent sheaf, defined in semi q-coronae of a complex space. Semi q-coronae are domains whose boundary is the union of a Levi flat part, a q-pseudoconvex part and a q-pseudoconcave part. Such results are obtained mainly using cohomological techniques.

[1] Fracture theory predicts that polygonal cracks will form in the presence of an isotropic, extensional stress field. On Venus, polygonal fractures are observed on scales several orders of magnitude larger than on Earth, with an average diameter of 1.8 ± 0.9 km. Proposed formation mechanisms include cooling following lava flow emplacement, lithospheric heating, and climate change. Here we exa...