Search Publications
Discovery and characterisation of long-period eclipsing binary stars from Kepler K2 campaigns 1, 2, and 3
Maxted, P. F. L.; Hutcheon, R. J.
Context. The Kepler K2 mission now makes it possible to find and study a wider variety of eclipsing binary stars than has been possible to-date, particularly long-period systems with narrow eclipses.
Aims: Our aim is to characterise eclipsing binary stars observed by the Kepler K2 mission with orbital periods longer than P ≈ 5.5 days.
Me…
Cassini radar observation of Punga Mare and environs: Bathymetry and composition
Lorenz, R. D.; Lunine, J. I.; Hayes, A. G. +4 more
In January 2015 (fly-by T108), the Cassini radar observed Punga Mare, Titan's northernmost and third-largest sea, in altimetry mode during closest approach. The ground track intercepted a section of the mare and a system of channels and flooded areas connecting Punga to Kraken Mare. We use a processing technique, successfully adopted for Ligeia Ma…
Demonstration of a Novel Method for Measuring Mass-loss Rates for Massive Stars
Kobulnicky, Henry A.; Povich, Matthew S.; Chick, William T.
The rate at which massive stars eject mass in stellar winds significantly influences their evolutionary path. Cosmic rates of nucleosynthesis, explosive stellar phenomena, and compact object genesis depend on this poorly known facet of stellar evolution. We employ an unexploited observational technique for measuring the mass-loss rates of O and ea…
Revealing the Broad Line Region of NGC 1275: The Relationship to Jet Power
Gurwell, Mark A.; Punsly, Brian; Marziani, Paola +2 more
NGC 1275 is one of the most conspicuous active galactic nuclei (AGN) in the local universe. The radio jet currently emits a flux density of ∼10 Jy at ∼1 mm wavelengths, down from the historic high of ∼65 Jy in 1980. Yet, the nature of the AGN in NGC 1275 is still controversial. It has been debated whether this is a broad emission line (BEL) Seyfer…
Consistent Iron Abundances Derived from Neutral and Singly Ionized Iron Lines in Ultraviolet and Optical Spectra of Six Warm Metal-poor Stars
Roederer, Ian U.; Sneden, Christopher; Cowan, John J. +3 more
Neutral Fe lines in metal-poor stars yield conflicting abundances depending on whether and how deviations from local thermodynamic equilibrium (LTE) are considered. We have collected new high-resolution and high signal-to-noise ultraviolet (UV) spectra of three warm dwarf stars with [Fe/H] ≈ -2.9 with the Space Telescope Imaging Spectrograph on th…
Vertical Oscillation of a Coronal Cavity Triggered by an EUV Wave
Ji, H. S.; Zhang, Q. M.
In this paper, we report our multiwavelength observations of the vertical oscillation of a coronal cavity on 2011 March 16. The elliptical cavity with an underlying horn-like quiescent prominence was observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. The width and height of the cavity are 150″ and 240″, and the c…
Multi-instrument view on solar eruptive events observed with the Siberian Radioheliograph: From detection of small jets up to development of a shock wave and CME
Grechnev, V. V.; Kochanov, A. A.; Uralov, A. M. +7 more
The first 48-antenna stage of the Siberian Radioheliograph (SRH) started single-frequency test observations early in 2016, and since August 2016 it routinely observes the Sun at several frequencies in the 4-8 GHz range with an angular resolution of 1-2 arc minutes and an imaging interval of about 12 s. With limited opportunities of the incomplete …
NLTE Analysis of Copper Lines in Different Stellar Populations
Zhao, G.; Shi, J. R.; Yan, H. L. +1 more
The copper abundances of 29 metal-poor stars are determined based on the high-resolution, high-signal-to-noise ratio spectra from the UVES spectrograph at the ESO VLT telescope. Our sample consists of the stars of the Galactic halo, thick- and thin-disk, with [Fe/H] ranging from ∼-3.2 to ∼0.0 dex. The non-local thermodynamic equilibrium (NLTE) eff…
On the Importance of the Nonequilibrium Ionization of Si IV and O IV and the Line of Sight in Solar Surges
Martínez-Sykora, J.; Moreno-Insertis, F.; Nóbrega-Siverio, D.
Surges are ubiquitous cool ejections in the solar atmosphere that often appear associated with transient phenomena like UV bursts or coronal jets. Recent observations from the Interface Region Imaging Spectrograph show that surges, although traditionally related to chromospheric lines, can exhibit enhanced emission in Si IV with brighter spectral …
Origin of Molecular Oxygen in Comets: Current Knowledge and Perspectives
Mousis, Olivier; Bouquet, Alexis; Lunine, Jonathan I. +10 more
The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument onboard the Rosetta spacecraft has measured molecular oxygen (O2) in the coma of comet 67P/Churyumov-Gerasimenko (67P/C-G) in surprisingly high abundances. These measurements mark the first unequivocal detection of O2 in a cometary environment. …