Search Publications
TESS observations of southern ultrafast rotating low-mass stars
Ramsay, Gavin; Doyle, Lauren; Doyle, J. Gerry
In our previous study of low-mass stars using TESS, we found a handful that show a periodic modulation on a period <1 d but also displayed no flaring activity. Here we present the results of a systematic search for ultrafast rotators (UFRs) in the Southern ecliptic hemisphere, which were observed in 2-min cadence with TESS. Using data from Gaia…
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…
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…
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…
Detection of the phase curve and occultation of WASP-100b with TESS
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)…
Outside the Lyman-break box: detecting Lyman continuum emitters at 3.5 < z < 5.1 with CLAUDS
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 $z$ …
H2 emission in the low-ionization structures of the planetary nebulae NGC 7009 and NGC 6543
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…
The Pristine survey XI: the FORS2 sample
Bonifacio, P.; Caffau, E.; Jablonka, P. +11 more
Extremely metal-poor (EMP) stars are old objects that mostly formed very early after the big bang. They are rare and, to select them, we have to rely on low-resolution spectroscopic or photometric surveys; specifically the combination of narrow- and broad-band photometry provides a powerful and time efficient way to select MP stars. The Pristine p…