The visual complexity of coronal mass ejections follows the solar cycle
Space Weather American Geophysical Union 18:10 (2020)
Abstract:
The Heliospheric Imagers on board National Aeronautics and Space Administration (NASA)'s twin STEREO spacecraft show that coronal mass ejections (CMEs) can be visually complex structures. To explore this complexity, we created a citizen science project with the U.K. Science Museum, in which participants were shown pairs of CME images and asked to decide which image in each pair appeared the most “complicated.” A Bradley‐Terry model was then applied to these data to rank the CMEs by their “complicatedness,” or “visual complexity.” This complexity ranking revealed that the annual average visual complexity values follow the solar activity cycle, with a higher level of complexity being observed at the peak of the cycle. The average complexity of CMEs observed by STEREO‐A was also found to be significantly higher than those observed by STEREO‐B. Visual complexity was found to be associated with CME size and brightness, but our results suggest that complexity may be influenced by the scale‐sizes of structure in the CMEs.Interactions among intermediate redshift galaxies
Astronomy & Astrophysics EDP Sciences 639 (2020) a30
TOI-1338: TESS' First Transiting Circumbinary Planet
ASTRONOMICAL JOURNAL 159:6 (2020) ARTN 253
Abstract:
© 2020. The American Astronomical Society. All rights reserved. We report the detection of the first circumbinary planet (CBP) found by Transiting Exoplanet Survey Satellite (TESS). The target, a known eclipsing binary, was observed in sectors 1 through 12 at 30 minute cadence and in sectors 4 through 12 at 2 minute cadence. It consists of two stars with masses of 1.1 M o˙ and 0.3 M o˙ on a slightly eccentric (0.16), 14.6 day orbit, producing prominent primary eclipses and shallow secondary eclipses. The planet has a radius of ∼6.9 R ⊕ and was observed to make three transits across the primary star of roughly equal depths (∼0.2%) but different durations-a common signature of transiting CBPs. Its orbit is nearly circular (e ≈ 0.09) with an orbital period of 95.2 days. The orbital planes of the binary and the planet are aligned to within ∼1°. To obtain a complete solution for the system, we combined the TESS photometry with existing ground-based radial-velocity observations in a numerical photometric-dynamical model. The system demonstrates the discovery potential of TESS for CBPs and provides further understanding of the formation and evolution of planets orbiting close binary stars.
TOI-1338: TESS' First Transiting Circumbinary Planet
The Astronomical Journal, Volume 159, Issue 6, id.253, 26 pp. (2020)
Abstract:
We report the detection of the first circumbinary planet found by TESS. The target, a known eclipsing binary, was observed in sectors 1 through 12 at 30-minute cadence and in sectors 4 through 12 at two-minute cadence. It consists of two stars with masses of 1.1 MSun and 0.3 MSun on a slightly eccentric (0.16), 14.6-day orbit, producing prominent primary eclipses and shallow secondary eclipses. The planet has a radius of ~6.9 REarth and was observed to make three transits across the primary star of roughly equal depths (~0.2%) but different durations -- a common signature of transiting circumbinary planets. Its orbit is nearly circular (e ~ 0.09) with an orbital period of 95.2 days. The orbital planes of the binary and the planet are aligned to within ~1 degree. To obtain a complete solution for the system, we combined the TESS photometry with existing ground-based radial-velocity observations in a numerical photometric-dynamical model. The system demonstrates the discovery potential of TESS for circumbinary planets, and provides further understanding of the formation and evolution of planets orbiting close binary stars.
Interactions among intermediate redshift galaxies. The case of SDSSJ134420.86+663717.8
ArXiv 2005.12888 (2020)