Search Publications
White-light QFP wave train and the associated failed breakout eruption
Yao, Surui; Shen, Yuandeng; Zhou, Chengrui +5 more
Quasi-periodic fast-propagating (QFP) magnetosonic wave trains are commonly observed in the low corona at extreme ultraviolet wavelength bands. Here, we report the first white-light imaging observation of a QFP wave train propagating outwardly in the outer corona ranging from 2 to 4 R⊙. The wave train was recorded by the Large Angle Spe…
Dynamo activity of the K dwarf KOI-883 from transit photometry mapping
Marsden, S. C.; Carter, B. D.; Valio, A. +1 more
The Kepler mission target star KOI-883 is notable in being a low-mass K2V dwarf with moderately fast 8.99-d rotation and hosting a single transiting hot Jupiter in a 2.69-d orbit. This combination thus presents a particular opportunity to study star-spot activity by using the many deep planetary transits apparent in the light curve to map the stel…
Simultaneous Detection of Optical Flares of the Magnetically Active M-dwarf Wolf359
Wang, Shiang-Yu; Zhang, Yu; Lehner, Matthew J. +13 more
We present detections of stellar flares of Wolf 359, an M6.5 dwarf in the solar neighborhood (2.41 pc) known to be prone to flares due to surface magnetic activity. The observations were carried out from 2020 April 23 to 29 with a 1 m and a 0.5 m telescope separated by nearly 300 km in Xinjiang, China. In 27 hr of photometric monitoring, a total o…
Extremely Inclined Orbit of the S-type Planet γ Cep Ab Induced by the Eccentric Kozai-Lidov Mechanism
Ji, Jianghui; Huang, Xiumin
γ Cep Ab is a typical S-type planet, which occupies a nearly perpendicular planetary orbit relative to the binary. Here, we use a Markov Chain Monte Carlo sampler to conduct a full N-body fitting and derive self-consistent orbital solutions for this hierarchical system. We then employ the eccentric Kozai-Lidov (EKL) mechanism to explain the extrem…
Pushing sub-arcsecond resolution imaging down to 30 MHz with the trans-European International LOFAR Telescope
Bondi, M.; Brunetti, G.; Callingham, J. R. +12 more
Relatively little information is available about the Universe at ultra-low radio frequencies (ULF; i.e., below 50 MHz), although the ULF spectral window contains a wealth of unique diagnostics for studying galactic and extragalactic phenomena. Subarcsecond resolution imaging at these frequencies is extremely difficult, due to the long baselines (&…
Discovery of Nine Super Li-rich Unevolved Stars from the LAMOST Survey
Wang, L.; Shi, J. -R.; Zhou, Y. -T. +7 more
Based on the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) medium-resolution spectroscopic survey (MRS), we report the discovery of nine super Li-rich unevolved stars with A(Li) > 3.8 dex. These objects show unusually high levels of lithium abundances, up to three times higher than the meteoritic value of 3.3 dex, which ind…
Gaia-ESO Survey: Detailed elemental abundances in red giants of the peculiar globular cluster NGC 1851
Gilmore, G.; Guiglion, G.; Lardo, C. +24 more
Context. NGC 1851 is one of several globular clusters for which multiple stellar populations of the subgiant branch have been clearly identified and a difference in metallicity detected. A crucial piece of information on the formation history of this cluster can be provided by the sum of A(C+N+O) abundances. However, these values have lacked a gen…
Observation of the Solar Corona Using Radio Scintillation with the Akatsuki Spacecraft: Difference Between Fast and Slow Wind
Matsumoto, Takuma; Pätzold, Martin; Imamura, Takeshi +8 more
The properties of the coronal plasma at heliocentric distances of 1.5 - 8.9 R⊙ (solar radii) were studied with radio-occultation observations using JAXA's Akatsuki spacecraft in 2016. Physical parameters that characterize the solar wind were retrieved from the intensity-scintillation time series by fitting a theoretical spectrum to the …
Machine learning for fast transients for the Deeper, Wider, Faster programme with the Removal Of BOgus Transients (ROBOT) pipeline
Mahabal, Ashish; Zhang, Jielai; Cooke, Jeff +3 more
The Deeper, Wider, Faster (DWF) programme is optimized to detect fast transients that show luminosity changes on time-scales of sub-second to days using fast cadence simultaneous observations and rapid response follow up. One of the significant bottlenecks in DWF is the time required to assess candidates for rapid follow up and to manually inspect…
Spectral Evolution of Dark Asteroid Surfaces Induced by Space Weathering over a Decade
Hasegawa, Sunao; Marsset, Michaël; Im, Myungshin +20 more
The surfaces of airless bodies like asteroids in the solar system are known to be affected by space weathering. Experiments simulating space weathering are essential for studying the effects of this process on meteorite samples, but the problem is that the time spent to reproduce space weathering in these experiments is billions of times shorter t…