Search Publications
K2-231 b: A Sub-Neptune Exoplanet Transiting a Solar Twin in Ruprecht 147
Torres, Guillermo; Vanderburg, Andrew; Huber, Daniel +9 more
We identify a sub-Neptune exoplanet (R p = 2.5 ± 0.2 {R}\oplus ) transiting a solar twin in the Ruprecht 147 star cluster (3 Gyr, 300 pc, [Fe/H] = +0.1 dex). The ∼81 day light curve for EPIC 219800881 (V = 12.71) from K2 Campaign 7 shows six transits with a period of 13.84 days, a depth of ∼0.06%, and a duration of ∼4 hr. B…
ALMA Detections of CO Emission in the Most Luminous, Heavily Dust-obscured Quasars at z > 3
Knudsen, Kirsten K.; Drouart, Guillaume; Fan, Lulu +1 more
We report the results of a pilot study of CO(4 - 3) emission line of three Wide-field Infrared Survey Explorer (WISE)-selected hyper-luminous, dust-obscured quasars (QSOs) with sensitive ALMA Band 3 observations. These obscured QSOs with L bol > 1014 L ⊙ are among the most luminous objects in the universe. All t…
Resolving the kinematics of the discs around Galactic B[e] supergiants
Vasilopoulos, G.; Borges Fernandes, M.; Kraus, M. +4 more
B[e] supergiants are luminous evolved massive stars. The mass-loss during this phase creates a complex circumstellar environment with atomic, molecular, and dusty regions usually found in rings or disc-like structures. For a better comprehension of the mechanisms behind the formation of these rings, detailed knowledge about their structure and dyn…
Pre-discovery Observations and Orbit of Comet C/2017 K2 (PANSTARRS)
Jewitt, David; Clark, David; Hui, Man-To
We present a study of comet C/2017 K2 (PANSTARRS) using pre-discovery archival data taken from 2013 to 2017. Our measurements show that the comet has been marginally increasing in activity since at least 2013 May (heliocentric distance of {r}{{H}}=23.7 {au} pre-perihelion). We estimate the mass-loss rate during the period 2013-2017 as \…
A closer look at the transition between fully convective and partly radiative low-mass stars
Baraffe, Isabelle; Chabrier, Gilles
Recently, an analysis of Gaia Data Release 2 revealed a gap in the mid-M dwarf main sequence. The authors suggested the feature is linked to the onset of full convection in M dwarfs. Following the announcement of this discovery, an explanation has been proposed based on standard stellar evolution models. In this paper we re-examine this explanatio…
Updated observational constraints on quintessence dark energy models
Ichiki, Kiyotomo; Sugiyama, Naoshi; Ooba, Junpei +1 more
The recent GW170817 measurement favors the simplest dark energy models, such as a single scalar field. Quintessence models can be classified in two classes, freezing and thawing, depending on whether the equation of state decreases towards -1 or departs from it. In this paper, we put observational constraints on the parameters governing the equati…
A Comprehensive Catalog of Galactic Eclipsing Binary Stars with Eccentric Orbits Based on Eclipse Timing Diagrams
Ogłoza, W.; Kim, H. -W.; Kim, C. -H. +3 more
A comprehensive catalog of 623 galactic eclipsing binary (EB) systems with eccentric orbits is presented with more than 2830 times of minima determined from the archived photometric data by various sky-survey projects and new photometric measurements. The systems are divided into two groups according to whether the individual system has a GCVS nam…
Anatomy of the hyper-runaway star LP 40-365 with Gaia
Hermes, J. J.; Gänsicke, B. T.; Hollands, M. A. +4 more
LP 40-365 (aka GD 492) is a nearby low-luminosity hyper-runaway star with an extremely unusual atmospheric composition, which has been proposed as the remnant of a white dwarf that survived a peculiar Type Iax supernova (SN Iax) in a single-degenerate scenario. Adopting the Gaia Data Release 2 (DR2) parallax, ϖ = 1.58 ± 0.03 mas, we estimate a rad…
Effective Induction Heating around Strongly Magnetized Stars
Lammer, H.; Fossati, L.; Lüftinger, T. +4 more
Planets that are embedded in the changing magnetic fields of their host stars can experience significant induction heating in their interiors caused by the planet’s orbital motion. For induction heating to be substantial, the planetary orbit has to be inclined with respect to the stellar rotation and dipole axes. Using WX UMa, for which the rotati…
Resolved Kinematics of Runaway and Field OB Stars in the Small Magellanic Cloud
Lennon, D. J.; Oey, M. S.; Castro, N. +6 more
We use Gaia Data Release 2 proper motions of field OB stars from the Runaways and Isolated O-Type Star Spectroscopic Survey of the Small Magellanic Cloud (SMC) to study the kinematics of runaway stars. The data reveal that the SMC Wing has a systemic peculiar motion relative to the SMC Bar of ({v}α ,{v}δ ) =(62+/- 7,-18+/- 5)…