Search Publications
CME Productive and Non-productive Recurring Jets Near an Active Region AR11176
Srivastava, Abhishek K.; Dwivedi, Bhola N.; Solanki, Ritika
We study the recurring jets near AR11176 during the period 2011 March 31 17:00 UT to April 1 05:00 UT using observations from the Atmospheric Imaging Assembly (AIA) on board Solar Dynamics Observatory (SDO). Mini-filaments (mini-filament1 & 2) are found at the base of these recurring jets where mini-filament1 shows the partial signature of eru…
Quantifying the Toroidal Flux of Preexisting Flux Ropes of Coronal Mass Ejections
Qiu, Jiong; Cheng, X.; Ding, M. D. +3 more
In past decades, much progress has been achieved in understanding the origin and evolution of coronal mass ejections (CMEs). In situ observations of the counterparts of CMEs, especially magnetic clouds (MCs) near the Earth, have provided measurements of the structure and total flux of CME flux ropes. However, it has been difficult to measure these…
A new spectroscopic analysis of the massive O + O type binary HD 54662 AB
Maíz Apellániz, J.; Fullerton, A. W.; Barbá, R. H. +9 more
HD 54662 AB is one of the three O + OB binaries known so far with orbital period longer than 1000 d, offering the opportunity to test scenarios of massive star formation and models of single stellar evolution. Here, we present a detailed study of this system based on new high-resolution spectra and data. A disentangling method is used to recover t…
A detailed view on the circumstellar environment of the M-type AGB star EP Aquarii. I. High-resolution ALMA and SPHERE observations
Decin, Leen; Montargès, Miguel; Millar, Tom J. +3 more
Cool evolved stars are known to be significant contributors to the enrichment of the interstellar medium through their dense and dusty stellar winds. High resolution observations of these outflows have shown them to possess high degrees of morphological complexity. We observed the asymptotic giant branch (AGB) star EP Aquarii with ALMA in band 6 a…
NLTE modeling and spectroscopically derived abundances of lithium and beryllium for classical nova ejecta
Shore, Steven N.; De Gennaro Aquino, Ivan
Context. Extreme super-solar abundances of lithium and beryllium have been reported in recent years for classical novae based on absorption lines in ultraviolet and optical spectra during the optically thick stages, but these findings have not been compared with spectrum syntheses of the ejecta.
Aims: We present a grid of nova ejecta models c…
Calibrating the Galactic Cepheid Period-Luminosity Relation from the Maximum-likelihood Technique
Lazovik, Yaroslav A.; Rastorguev, Alexey S.
We present a realization of the maximum-likelihood technique, which is one of the latest modifications of the Baade-Becker-Wesselink method. Our approach is based on nonlinear calibrations of the effective temperature and bolometric correction, which take into account metallicity and surface gravity. It allows one to estimate the key Cepheid param…
Rotation of open clusters based on Gaia data. Praesepe
Popov, Alexander A.; Loktin, Alexander V.
High–precision trigonometric parallaxes, proper motions, and radial velocities of the Gaia DR2 catalog allow us to investigate the problem of open clusters rotation. Such a study could naturally be started with the clusters closest to the Sun, so we chose Praesepe as an object of our study. We selected 908 probable cluster members up to the appare…
Extending Gaia DR2 with HST narrow-field astrometry - II. Refining the method on WISE J163940.83-684738.6
Bedin, L. R.; Fontanive, C.
In the second paper of this series, we perfected our method of linking high-precision Hubble Space Telescope astrometry to the high-accuracy Gaia DR2 absolute reference system to overcome the limitations of relative astrometry with narrow-field cameras. Our test case here is the Y brown dwarf WISE J163940.83-684738.6, observed at different epochs …
Visual Orbits of Spectroscopic Binaries with the CHARA Array. III. HD 8374 and HD 24546
Gies, Douglas R.; Lester, Kathryn V.; Monnier, John D. +9 more
We present the visual orbits of two long-period spectroscopic binary stars, HD 8374 and HD 24546, using interferometric observations acquired with the CHARA Array and the Palomar Testbed Interferometer. We also obtained new radial velocities from echelle spectra using the APO 3.5 m and Fairborn 2.0 m telescopes. By combining the visual and spectro…
Secular changes in the orbits of the quadruple system VW LMi
Kundra, E.; Budaj, J.; Szabó, Gy M. +8 more
VW LMi is the tightest known quadruple system with 2 + 2 hierarchy. It consists of a W UMa-type eclipsing binary (P12 = 0.477 55 d) and another detached non-eclipsing binary (P34 = 7.93 d) orbiting around a common centre of mass in about P1234 = 355 d. We present new observations of the system extending the time ba…