Search Publications
The hot limit of solar-like oscillations from Kepler photometry
Balona, Luis A.
Kepler short-cadence photometry of 2347 stars with effective temperatures in the range 6000 - 10000 K was used to search for the presence of solar-like oscillations. The aim is to establish the location of the hot end of the stochastic convective excitation mechanism and to what extent it may overlap the δ Scuti/γ Doradus instability region. A sim…
On the Pulsations of the δ Scuti Star of the Binary System KIC 6629588
Liakos, A.
This work includes a comprehensive analysis of the Kepler detached eclipsing binary system KIC 6629588 that aims at the detailed study of the oscillation properties of its pulsating component. Ground-based spectroscopic observations were obtained and used to classify the components of the system. The spectroscopic results were used as constraints …
Nonlinear Color-Metallicity Relations of Globular Clusters. IX. Different Radial Number Density Profiles between Blue and Red Clusters
Chung, Chul; Lee, Sang-Yoon; Yoon, Suk-Jin
The optical colors of globular clusters (GCs) in most large early-type galaxies are bimodal. Blue and red GCs show a sharp difference in the radial profile of their surface number density in the sense that red GCs are more centrally concentrated than blue GCs. An instant interpretation is that there exist two distinct GC subsystems having differen…
Estimating the Ages of FGK Dwarf Stars through the Use of GALEX FUV Magnitudes
Crandall, Sara; Smith, Graeme H.; Subramonian, Arjun +2 more
Stellar age cannot be directly measured, yet age determinations are fundamental to understanding the evolution of stars, planets, and galaxies. The work presented here builds upon the idea of a stellar-activity age. We utilized far-ultraviolet (FUV) photometry acquired by the Galaxy Evolution Explorer (GALEX) space telescope as an indicator of chr…
VLT/SPHERE survey for exoplanets around young early-type stars, including systems with multi-belt architectures
Minniti, D.; Bayo, A.; Girard, J. +21 more
Context. Dusty debris disks around pre- and main-sequence stars are potential signposts for the existence of planetesimals and exoplanets. Giant planet formation is therefore expected to play a key role in the evolution of the disk. This is indirectly confirmed by extant submillimeter near-infrared images of young protoplanetary and cool dusty deb…
Frontal Aureole Deposit on Acheron Fossae ridge as evidence for landslide-generated tsunami on Mars
De Blasio, Fabio Vittorio
The recurrent failures of the 8 to 10-km high basal scarp of the Olympus Mons volcano on Mars has resulted in enormous landslides merging into a composite deposit known as the aureole. The largest of these landslides, the western (W) aureole, appears as a hummocky and extensive tongue reaching the distance of 700 km from the present Olympus Mons e…
A Generalized Fisk-type HMF: Implications of Spatially Dependent Photospheric Differential Rotation
Burger, R. A.; Steyn, P. J.
The existence of a Fisk-type heliospheric magnetic field (HMF) has been debated ever since Fisk proposed an alternative to the traditional view of the HMF first proposed by Parker. Several modifications of the original Fisk field model have been published in the past, for example, the Schwadron field and the Fisk-Parker hybrid HMF model. This stud…
Faint Standards for ZYJHK from the UKIDSS and VISTA Surveys
Leggett, S. K.; Hambly, Nigel C.; Cross, Nicholas J. G.
The currently defined 'United Kingdom Infrared Telescope (UKIRT) Faint Standards' have JHK magnitudes between 10 and 15, with Kmedian = 11.2. These stars will be too bright for the next generation of large telescopes. We have used multi-epoch observations taken as part of the UKIRT Infrared Deep Sky Survey (UKIDSS) and the Visible and I…
Constraints on the Abundance of 0.01 c Stellar Engines in the Milky Way
Lingam, Manasvi; Loeb, Abraham
Stellar engines are hypothesized megastructures that extract energy from the host star, typically with the purpose of generating thrust and accelerating the stellar system. We explore the maximum potential speeds that could be realizable by stellar engines, and determine that speeds up to ∼0.1 c might perhaps be attainable under optimal conditions…
Suzaku and Fermi view of the supernova remnant 3C 396
Kisaka, S.; Sezer, A.; Yamazaki, R. +4 more
3C 396 is a composite supernova remnant (SNR), consisting of a central pulsar wind nebula (PWN) and a bright shell in the west, which is known to be interacting with molecular clouds (MCs). We present a study of X-ray emission from the shell and the PWN of the SNR 3C 396 using archival Suzaku data. The spectrum of the SNR shell is clearly thermal,…