Search Publications
Digitization and astrometric calibration of Carte du Ciel photographic plates with Gaia DR1
Prusti, T.; Ness, J. -U.; Muinonen, K. +7 more
Context. Carte du Ciel was a global international project at the end of the nineteenth and beginning of the twentieth century to map the sky to about magnitude 14 on photographic plates. The full project was never observationally completed and a large fraction of the observations made remain unanalyzed.
Aims: We want to study whether the astr…
Interferometric Observations of the Quiet Sun at 20 and 25 MHz in May 2014
Rucker, H. O.; Poedts, S.; Melnik, V. N. +3 more
We present the results of solar observations at 20 and 25 MHz with the Ukrainian T-shaped Radio telescope of the second modification (UTR-2) in the interferometric session from 27 May to 2 June 2014. In this case, the different baselines 225, 450, and 675 m between the sections of the east-west and north-south arms of UTR-2 were used. On 29 May 20…
Absolute parameters and period variation in a semidetached eclipsing variable V2247 Cyg
Volkov, I. M.; Ikonnikova, N. P.; Burlak, M. A.
We aim to determine the absolute parameters of the components of a poorly studied Algol-type eclipsing binary V2247 Cyg. The data analysis is based on our numerous precise UBVRcIc photometric observations and low resolution spectra. The photometric solution reveals a semi-detached configuration with a less-massive component filling its Roche lobe.…
Formation and degradation of chaotic terrain in the Galaxias regions of Mars: implications for near-surface storage of ice
Conway, Susan J.; Gallagher, Colman; Balme, Matt +1 more
Galaxias Chaos is a region of low plateaus separated by narrow fractures - a chaotic terrain. Galaxias Mensae and Galaxias Colles are characterised by mesa and knobby terrains of individual landforms, or small assemblages, separated by plains. Galaxias Chaos has been attributed to ground disturbance due to sublimation in shallow subsurface ice-ric…
The Eye of Saturn's North Polar Vortex: Unexpected Cloud Structures Observed at High Spatial Resolution by Cassini/VIMS
Sotin, C.; Brown, R. H.; Baines, K. H. +6 more
Near-infrared spectral maps of Saturn's north polar vortex obtained at high spatial resolution provided by Cassini/Visual Infrared Mapping Spectrometer (VIMS) reveal localized ammonia clouds composed of unusually large particles exceeding 13 µm in radius, the largest cloud particles documented during the Cassini mission. Taken under near-opt…
Kepler-62f: Kepler's first small planet in the habitable zone, but is it real?
Hedges, Christina; Agol, Eric; Borucki, William +1 more
Kepler-62f is the first exoplanet small enough to plausibly have a rocky composition orbiting within the habitable zone (HZ) discovered by the Kepler Mission. The planet is 1.4 times the size of the Earth and has an orbital period of 267 days. At the time of its discovery, it had the longest period of any small planet in the habitable zone of a mu…
The Search for Activity on Dione and Tethys With Cassini VIMS and UVIS
Brown, R. H.; Baines, K. H.; Buratti, B. J. +6 more
During the Cassini mission the Saturnian moons Dione and Tethys showed intriguing and multiple clues suggesting residual geologic activity that might be detectable as an atmosphere, plume, or even heat signature. These clues included an atmospheric aura around Dione, injection of particles into Saturn's magnetosphere, mysterious red streaks on Tet…
The photocentre-AGN displacement: is M87 actually harbouring a displaced supermassive black hole?
Prieto, M. A.; López-Navas, E.
M87 has been identified as a displaced supermassive black hole (SMBH) candidate. We investigated this possibility by a temporal analysis of 12 adaptive-optics assisted VLT and HST images spanning 20 yr. We found that the centre of the isophotal fitting to the nuclear region of M87 - assumed to mark the centre of mass of the galaxy - changes locati…
Flare-related Recurring Active Region Jets: Evidence for Very Hot Plasma
Del Zanna, Giulio; Shimizu, Toshifumi; Mulay, Sargam M. +3 more
We present a study of two active region jets (AR jets) that are associated with two C-class X-ray flares. The recurrent, homologous jets originated from the northern periphery of a sunspot. We confirm flare-like temperatures at the footpoints of these jets using spectroscopic observations of Fe XXIII (263.76 Å) and Fe XXIV (255.11 Å) emission line…
Investigating the Relation between Sunspots and Umbral Dots
Mathew, Shibu K.; Louis, Rohan E.; Yadav, Rahul
Umbral dots (UDs) are transient, bright features observed in the umbral region of a sunspot. We study the physical properties of UDs observed in sunspots of different sizes. The aim of our study is to relate the physical properties of UDs with the large-scale properties of sunspots. For this purpose, we analyze high-resolution G-band images of 42 …