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The first photometric analysis and period investigation of the K-type W UMa type binary system V0842 Cep
Li, Kai; Liu, Yuan; Li, Yu-Yang
V0842 Cep is a W UMa-type binary star that has been neglected since its discovery. We analysed the VRcIc light curves, obtained by the 1 m telescope at Weihai Observatory of Shandong University, using the Wilson-Devinney code. V0842 Cep was found to be a shallow contact binary system (f = 8.7%) with a mass ratio of 2.281. Bec…
SN 2019hcc: a Type II supernova displaying early O II lines
Gromadzki, Mariusz; Pignata, Giuliano; Galbany, Lluis +18 more
We present optical spectroscopy together with ultraviolet, optical, and near-infrared photometry of SN 2019hcc, which resides in a host galaxy at redshift 0.044, displaying a sub-solar metallicity. The supernova spectrum near peak epoch shows a 'w' shape at around 4000 Å which is usually associated with O II lines and is typical of Type I superlum…
Mapping a duck: geological features and region definitions on comet 67P/Churyumov-Gerasimenko
Küppers, M.; Besse, S.; Grieger, B. +1 more
The data from the Rosetta mission have permitted a reconstruction of the shape of comet 67P/Churyumov-Gerasimenko and an identification of the terrains and features forming the surface. The peculiar shape of the comet has made it challenging to project these geological features onto an unambiguous frame. As a result, the geological maps published …
AGB and RGB stars in the dwarf irregular galaxy Leo A
Stonkutė, Rima; Vansevičius, Vladas; Leščinskaitė, Alina
Context. Leo A is a gas-rich dwarf irregular galaxy of low stellar mass located in the outskirts of the Local Group. It has an extended star formation history with stellar populations spanning a wide age range (∼0.01−10 Gyr). As Leo A is a well-isolated dwarf galaxy, it is a perfect target to study a galactic structure formed entirely by processes…
Tracking the Source of Solar Type II Bursts through Comparisons of Simulations and Radio Data
Kasper, Justin C.; Hegedus, Alexander M.; Manchester, Ward B.
The most intense solar energetic particle events are produced by coronal mass ejections (CMEs) accompanied by intense type II radio bursts below 15 MHz. Understanding where these type II bursts are generated relative to an erupting CME would reveal important details of particle acceleration near the Sun, but the emission cannot be imaged on Earth …
Possible Detection of X-Ray Emitting Circumstellar Material in the Synchrotron-dominated Supernova Remnant RX J1713.7-3946
Acero, Fabio; Katsuda, Satoru; Terada, Yukikatsu +4 more
We report on a discovery of an X-ray emitting circumstellar material (CSM) knot inside the synchrotron dominant supernova remnant RX J1713.7-3946. This knot was previously thought to be a Wolf-Rayet star (WR 85), but we realized that it is in fact ~40″ away from WR 85, indicating no relation to WR 85. We performed high-resolution X-ray spectroscop…
The relationship between bipolar magnetic regions and their sunspots
Solanki, S. K.; Yeo, K. L.; Krivova, N. A. +1 more
Context. The relationship between bipolar magnetic regions (BMRs) and their sunspots is an important property of the solar magnetic field, but it is not well constrained. One consequence is that it is a challenge for surface flux transport models (SFTMs) based on sunspot observations to determine the details of BMR emergence, which they require as…
AX UMa, an ab-type RR Lyrae Star with a Rapidly Decreasing Pulsation Period, and Its Binarity
Qian, S. -B.; He, J. -J.; Zhu, L. -Y. +2 more
The pulsation periods of RR Lyrae stars usually vary with time, and they are often used as probes to study the mechanism behind the variation. After the early discovery that the pulsation period of the RR Lyrae star AX UMa decreased rapidly, in further research, we made multiband photometric observations of this star using the Sino-Thai 70 cm tele…
Disentangling the Physical Origin of Emission Line Ratio Offsets at High Redshift with Spatially Resolved Spectroscopy
Cooper, M. C.; Martin, Crystal L.; Treu, Tommaso +6 more
We present spatially resolved Hubble Space Telescope grism spectroscopy of 15 galaxies at z ~ 0.8 drawn from the DEEP2 survey. We analyze Hα+[N II], [S II], and [S III] emission on kiloparsec scales to explore which mechanisms are powering emission lines at high redshifts, testing which processes may be responsible for the well-known offset of hig…
The wide upper main sequence and main-sequence turnoff of the ∼ 800 Myr old star cluster NGC 1831
Bellini, Andrea; Goudfrooij, Paul; Correnti, Matteo +1 more
We present the analysis of the colour-magnitude diagram (CMD) morphology of the ~800 Myr old star cluster NGC 1831 in the Large Magellanic Cloud, exploiting deep, high-resolution photometry obtained using the Wide Field Camera 3 onboard the Hubble Space Telescope. We perform a simultaneous analysis of the wide upper main sequence and main-sequence…