Search Publications
A significant mutual inclination between the planets within the π Mensae system
De Rosa, Robert J.; Nielsen, Eric L.; Dawson, Rebekah
Context. Measuring the geometry of multi-planet extrasolar systems can provide insight into their dynamical history and the processes of planetary formation. These types of measurements are challenging for systems that are detected through indirect techniques such as radial velocity and transit, having only been measured for a handful of systems t…
Discovery of six new strongly magnetic white dwarfs in the 20 pc local population
Landstreet, John D.; Bagnulo, Stefano
The sample of white dwarfs included in the local 20 pc volume documents, fairly accurately, the total production of white dwarfs over roughly 10 Gyr of stellar evolution in this part of the Milky Way Galaxy. In this sample, we have been systematically searching for magnetic white dwarfs. Here we report the discovery of six new magnetic white dwarf…
A Deep View into the Nucleus of the Sagittarius Dwarf Spheroidal Galaxy with MUSE. II. Kinematic Characterization of the Stellar Populations
Mastrobuono-Battisti, A.; Kacharov, N.; Böker, T. +9 more
The Sagittarius dwarf spheroidal galaxy is in an advanced stage of disruption but still hosts its nuclear star cluster (NSC), M54, at its center. In this paper, we present a detailed kinematic characterization of the three stellar populations present in M54: young metal-rich (YMR); intermediate-age metal-rich (IMR); and old metal-poor (OMP), based…
Modeling of the Variable Circumstellar Absorption Features of WD 1145+017
Xu, S.; Dufour, P.; Fortin-Archambault, M.
We present an eccentric precessing gas disk model designed to study the variable circumstellar absorption features detected for WD 1145+017, a metal polluted white dwarf with an actively disintegrating asteroid around it. This model, inspired by one recently proposed by Cauley et al., calculates explicitly the gas opacity for any predetermined phy…
The CARMENES search for exoplanets around M dwarfs. Convective shift and starspot constraints from chromatic radial velocities
Amado, P. J.; Bauer, F. F.; Caballero, J. A. +26 more
Context. Variability caused by stellar activity represents a challenge to the discovery and characterization of terrestrial exoplanets and complicates the interpretation of atmospheric planetary signals.
Aims: We aim to use a detailed modeling tool to reproduce the effect of active regions on radial velocity measurements, which aids the ident…
TESS observations of Be stars: a new interpretation
Balona, L. A.; Ozuyar, D.
Light curves of 57 classical Be stars in TESS sectors 1-15 are examined. In most Be stars, the periodogram shows groups at a fundamental and one or more harmonics, which we attribute to rotation. In about 40 per cent of the stars, the group is just a single narrow or slightly broadened peak. In about 30 per cent, it consists of a multiple, closely…
Kinematics and dynamics of Gaia red clump stars. Revisiting north-south asymmetries and dark matter density at large heights
Robin, Annie C.; Famaey, Benoit; Bienaymé, Olivier +2 more
In this study, we analyse the kinematics and dynamics of a homogeneous sample of red clump stars, selected from the second Gaia data release catalogue in the direction of the Galactic poles, at five different positions in the plane. The level of completeness of the sample at heights between 0.6 and 3.5 kpc was asserted through a comparison with th…
The Milky Way's Shell Structure Reveals the Time of a Radial Collision
Widrow, Lawrence M.; Sanderson, Robyn; Newberg, Heidi Jo +1 more
We identify shell structures in the Milky Way for the first time. We find two shells in the Virgo Overdensity region and two shells in the Hercules Aquila Cloud region using Sloan Digital Sky Survey, Gaia, and LAMOST data. These shell stars are a subset of the substructure previously identified as the Virgo Radial Merger (VRM). Timing arguments fo…
Tidal Inflation Reconciles Low-density Sub-Saturns with Core Accretion
Batygin, Konstantin; Millholland, Sarah; Petigura, Erik
While the solar system contains no planets between the sizes of Uranus and Saturn, our current exoplanet census includes several dozen such planets with well-measured masses and radii. These sub-Saturns exhibit a diversity of bulk densities, ranging from ∼0.1 to 3 g cm-3. When modeled simply as hydrogen/helium envelopes atop rocky cores…
The MUSE-Faint survey. I. Spectroscopic evidence for a star cluster in Eridanus 2 and constraints on MACHOs as a constituent of dark matter
Bacon, Roland; Boogaard, Leindert A.; Brinchmann, Jarle +9 more
Aims: It has been shown that the ultra-faint dwarf galaxy Eridanus 2 may host a stellar cluster in its centre. If this cluster is shown to exist, it can be used to set constraints on the mass and abundance of massive astrophysical compact halo objects (MACHOs) as a form of dark matter. Previous research has shown promising expectations in the…