Search Publications
Stellar occultations enable milliarcsecond astrometry for Trans-Neptunian objects and Centaurs
Naletto, G.; Pál, A.; Snodgrass, C. +66 more
Context. Trans-Neptunian objects (TNOs) and Centaurs are remnants of our planetary system formation, and their physical properties have invaluable information for evolutionary theories. Stellar occultation is a ground-based method for studying these distant small bodies and has presented exciting results. These observations can provide precise pro…
A statistical study of plasmoids associated with a post-CME current sheet
Pant, Vaibhav; Banerjee, Dipankar; Patel, Ritesh +1 more
Context. Coronal mass ejections (CMEs) are often observed to be accompanied by flare, current sheets, and plasmoids/plasma blobs. 2D and 3D numerical simulations and observations reported plasmoids moving upward as well as downward along the current sheet.
Aims: We aim to investigate the properties of plasmoids observed in the current sheet f…
Most EL CVn systems are inner binaries of hierarchical triples
Gänsicke, B. T.; Parsons, S. G.; Schreiber, M. R. +2 more
In spite of their importance for modern astronomy, we do not fully understand how close binary stars containing at least one white dwarf form from main-sequence binary stars. The discovery of EL CVn binaries, close pre-white dwarfs with A/F main-sequence star companions, offers now the unique possibility to test models of close compact binary star…
Distribution of methanol and cyclopropenylidene around starless cores★
Nagy, Z.; Caselli, P.; Spezzano, S. +3 more
Context. The spatial distribution of molecules around starless cores is a powerful tool for studying the physics and chemistry governing the earliest stages of star formation.
Aims: Our aim is to study the chemical differentiation in starless cores to determine the influence of large-scale effects on the spatial distribution of molecules with…
K2 Ultracool Dwarfs Survey - VI. White light superflares observed on an L5 dwarf and flare rates of L dwarfs
Mullan, D. J.; Burgasser, A. J.; Gizis, J. E. +3 more
Kepler K2 long cadence data are used to study white light flares in a sample of 45 L dwarfs. We identified 11 flares on 9 L dwarfs with equivalent durations of (1.3-198) h and total (UV/optical/IR) energies of ≥0.9 × 1032 erg. Two superflares with energies of >1033 erg were detected on an L5 dwarf (VVV BD001): this is the …
The 2019 eruption of recurrent nova V3890 Sgr: observations by Swift, NICER, and SMARTS
Ness, J. -U.; Orio, M.; Osborne, J. P. +6 more
V3890 Sgr is a recurrent nova that has been seen in outburst three times so far, with the most recent eruption occurring on 2019 August 27 UT. This latest outburst was followed in detail by the Neil Gehrels Swift Observatory, from less than a day after the eruption until the nova entered the Sun observing constraint, with a small number of additio…
Superflares on the late-type giant KIC 2852961. Scaling effect behind flaring at different energy levels
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…
The possible disappearance of a massive star in the low-metallicity galaxy PHL 293B
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…
LRG-BEASTS: ground-based detection of sodium and a steep optical slope in the atmosphere of the highly inflated hot-saturn WASP-21b
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…
Bayesian Approach for Determining Microlens System Properties with High-angular-resolution Follow-up Imaging
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…