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Venus Express radio occultation observed by PRIDE
Wang, W.; Zheng, W.; Bocanegra-Bahamón, T. M. +18 more
Context. Radio occultation is a technique used to study planetary atmospheres by means of the refraction and absorption of a spacecraft carrier signal through the atmosphere of the celestial body of interest, as detected from a ground station on Earth. This technique is usually employed by the deep space tracking and communication facilities (e.g.…
Kinematics and Energetics of the EUV Waves on 11 April 2013
Srivastava, A. K.; Chen, P. F.; Uddin, Wahab +3 more
In this study, we present the observations of extreme-ultraviolet (EUV) waves associated with an M6.5 flare on 2013 April 11. The event was observed by Solar Dynamics Observatory (SDO) in different EUV channels. The flare was also associated with a halo CME and type II radio bursts. We observed both fast and slow components of the EUV wave. The sp…
C IV absorbers tracing cool gas in dense galaxy group/cluster environments
Charlton, Jane C.; Muzahid, Sowgat; Narayanan, Anand +3 more
We present analysis on three intervening H I-C IV absorption systems tracing gas within galaxy group/cluster environments, identified in the HST/COS far-UV spectra of the background quasars PG 1148 + 549 (zabs = 0.003 46), SBS 1122 + 594 (zabs = 0.004 02), and RXJ 1230.8 + 0115 (zabs = 0.005 74). The ionization mod…
Photospheric nitrogen abundances and carbon 12C/13C ratios of red giant stars
Sato, Bun'ei; Omiya, Masashi; Harakawa, Hiroki +1 more
Nitrogen abundances and carbon isotope ratios (12C/13C) in the atmospheres of red giants are known to be influenced by dredge-up of H-burning products, and serve as useful probes to study the nature of evolution-induced envelope mixing. We determined the [N/Fe] and 12C/13C ratios for 239 late-G/early-K g…
An Optical and X-Ray Study of the Contact Binary, BH Cassiopeia
Zheng, Jie; Zhang, Yu; Esamdin, Ali +10 more
We present the revised and high-quality CCD time series observations in 2017 and 2018 of the W UMa-type contact binary BH Cas. The combination of our new determinations of minimum times and those collected from the literatures reveal a long-term period increase with a rate of dP/dt = +3.27 × 10-7 day yr-1, which can be accoun…
A Joint NICER and XMM-Newton View of the “Magnificent” Thermally Emitting X-Ray Isolated Neutron Star RX J1605.3+3249
Enoto, Teruaki; Bogdanov, Slavko; Ray, Paul S. +11 more
Thermally emitting X-ray isolated neutron stars (NSs) represent excellent targets for testing cooling surface emission and atmosphere models, which are used to infer the physical parameters of the NS. Among the seven known members of this class, RX J1605.3+3249 is the only one that still lacks confirmation of its spin period. Here we analyze NICER…
Solar Active Region Heating Diagnostics from High-temperature Emission Using the MaGIXS
Golub, Leon; Winebarger, Amy R.; Warren, Harry P. +7 more
The relative amount of high-temperature plasma has been found to be a useful diagnostic to determine the frequency of coronal heating on sub-resolution structures. When the loops are infrequently heated, a broad emission measure (EM) over a wider range of temperatures is expected. A narrower EM is expected for high-frequency heating where the loop…
Gaia DR2 orbital properties for field stars with globular cluster-like CN band strengths
Posti, L.; Savino, A.
Context. Large spectroscopic surveys of the Milky Way have revealed that a small population of stars in the halo have light element abundances comparable to those found in globular clusters. The favoured explanation for the peculiar abundances of these stars is that they originated inside a globular cluster and were subsequently lost.
Aims: U…
Hemispheric asymmetry in meridional flow and the sunspot cycle
Antia, H. M.; Nandy, Dibyendu; Lekshmi, B.
Magnetohydrodynamic dynamo modelling shows that the large-scale solar meridional plasma flow plays an important role in governing the dynamics of the sunspot cycle. Observations indicate that meridional flow velocities at each solar latitude and depth vary over time and are asymmetric across the equator. Here, using helioseismic observations we ex…
Monitoring the Superorbital Period Variation and Spin Period Evolution of SMC X-1
Enoto, Teruaki; Ueda, Yoshihiro; Hu, Chin-Ping +2 more
The X-ray pulsar SMC X-1 shows a superorbital modulation with an unstable cycle length in the X-ray band. We present its timing behaviors, including the spin, orbital, and superorbital modulations, beyond the end of the Rossi X-ray Timing Explorer mission. The time-frequency maps derived by the wavelet Z-transform and the Hilbert-Huang transform s…