Search Publications

Superflares on the late-type giant KIC 2852961. Scaling effect behind flaring at different energy levels
DOI: 10.1051/0004-6361/202038397 Bibcode: 2020A&A...641A..83K

Kriskovics, L.; Günther, M. N.; Bhatti, W. +7 more

Context. The most powerful superflares reaching 1039 erg bolometric energy are from giant stars. The mechanism behind flaring is thought to be the magnetic reconnection, which is closely related to magnetic activity (including starspots). However, it is poorly understood how the underlying magnetic dynamo works and how the flare activit…

2020 Astronomy and Astrophysics
Gaia 19
The possible disappearance of a massive star in the low-metallicity galaxy PHL 293B
DOI: 10.1093/mnras/staa1629 Bibcode: 2020MNRAS.496.1902A

Smith, Nathan; Mehner, Andrea; Groh, Jose H. +4 more

We investigate a suspected very massive star in one of the most metal-poor dwarf galaxies, PHL 293B. Excitingly, we find the sudden disappearance of the stellar signatures from our 2019 spectra, in particular the broad H lines with P Cygni profiles that have been associated with a massive luminous blue variable (LBV) star. Such features are absent…

2020 Monthly Notices of the Royal Astronomical Society
eHST 19
LRG-BEASTS: ground-based detection of sodium and a steep optical slope in the atmosphere of the highly inflated hot-saturn WASP-21b
DOI: 10.1093/mnras/staa2315 Bibcode: 2020MNRAS.497.5182A

Kirk, J.; Louden, T.; Wheatley, P. J. +7 more

We present the optical transmission spectrum of the highly inflated Saturn-mass exoplanet WASP-21b, using three transits obtained with the ACAM instrument on the William Herschel Telescope through the LRG-BEASTS survey (Low Resolution Ground-Based Exoplanet Atmosphere Survey using Transmission Spectroscopy). Our transmission spectrum covers a wave…

2020 Monthly Notices of the Royal Astronomical Society
eHST 19
Bayesian Approach for Determining Microlens System Properties with High-angular-resolution Follow-up Imaging
DOI: 10.3847/1538-3881/ab8adf Bibcode: 2020AJ....159..268K

Bennett, David P.; Koshimoto, Naoki; Suzuki, Daisuke

We present the details of the Bayesian analysis of the planetary microlensing event MOA-2016-BLG-227, whose excess flux is likely due to a source/lens companion or an unrelated ambient star, as well as of the assumed prior distributions. Furthermore, we apply this method to four reported planetary events, MOA-2008-BLG-310, MOA-2011-BLG-293, OGLE-2…

2020 The Astronomical Journal
eHST 19
Detection of the phase curve and occultation of WASP-100b with TESS
DOI: 10.1093/mnras/staa814 Bibcode: 2020MNRAS.494.4077J

Kipping, David; Jansen, Tiffany

We report the detection of the full orbital phase curve and occultation of the hot-Jupiter WASP-100b using TESS photometry. The phase curve is isolated by suppressing low-frequency stellar and instrumental modes using both a non-parametric harmonic notch filter (phasma) and semi-sector long polynomials. This yields a phase-curve signal of (73 ± 9)…

2020 Monthly Notices of the Royal Astronomical Society
Gaia 19
Coordination of the in situ payload of Solar Orbiter
DOI: 10.1051/0004-6361/201936894 Bibcode: 2020A&A...642A...5W

Lewis, G. R.; Livi, S.; Müller, D. +36 more

Solar Orbiter's in situ coordination working group met frequently during the development of the mission with the goal of ensuring that its in situ payload has the necessary level of coordination to maximise science return. Here we present the results of that work, namely how the design of each of the in situ instruments (EPD, MAG, RPW, SWA) was gu…

2020 Astronomy and Astrophysics
SolarOrbiter 19
Outer Radiation Belt Electron Lifetime Model Based on Combined Van Allen Probes and Cluster VLF Measurements
DOI: 10.1029/2020JA028018 Bibcode: 2020JGRA..12528018A

Aryan, Homayon; Boynton, Richard; Balikhin, Michael A. +4 more

The flux of energetic electrons in the outer radiation belt shows a high variability. The interactions of electrons with very low frequency (VLF) chorus waves play a significant role in controlling the flux variation of these particles. Quantifying the effects of these interactions is crucially important for accurately modeling the global dynamics…

2020 Journal of Geophysical Research (Space Physics)
Cluster 19
Outside the Lyman-break box: detecting Lyman continuum emitters at 3.5 < z < 5.1 with CLAUDS
DOI: 10.1093/mnras/staa920 Bibcode: 2020MNRAS.494.4986M

Ryan-Weber, E. V.; Arnouts, S.; Sawicki, M. +12 more

Identifying non-contaminated sample of high-redshift galaxies with escaping Lyman continuum (LyC) flux is important for understanding the sources and evolution of cosmic reionization. We present CLAUDS (CFHT Large Area u-band deep survey) u-band photometry of the COSMOS field to probe LyC radiation from spectroscopically confirmed galaxies at $z$ …

2020 Monthly Notices of the Royal Astronomical Society
eHST 19
H2 emission in the low-ionization structures of the planetary nebulae NGC 7009 and NGC 6543
DOI: 10.1093/mnras/staa515 Bibcode: 2020MNRAS.493.3800A

Gonçalves, Denise R.; Akras, Stavros; Ramos-Larios, Gerardo +1 more

Despite the many studies in the last decades, the low-ionization structures (LISs) of planetary nebulae (PNe) still hold several mysteries. Recent imaging surveys have demonstrated that LISs are composed of molecular gas. Here, we report H2 emission in the LISs of NGC 7009 and NGC 6543 by means of very deep narrow-band H2 ima…

2020 Monthly Notices of the Royal Astronomical Society
eHST 19
Time evolution of dust deposits in the Hapi region of comet 67P/Churyumov-Gerasimenko
DOI: 10.1051/0004-6361/202037485 Bibcode: 2020A&A...636A..91C

Sierks, H.; Fulle, M.; Kührt, E. +25 more


Aims: We provide a measurement of the seasonal evolution of the dust deposit erosion and accretion in the Hapi region of comet 67P/Churyumov-Gerasimenko with a vertical accuracy of 0.2-0.9 m.
Methods: We used OSIRIS Narrow Angle Camera images with a spatial scale of lower than 1.30 m px-1 and developed a tool to monitor the ti…

2020 Astronomy and Astrophysics
Rosetta 19