Search Publications
Birds of a Feather? Magellan/IMACS Spectroscopy of the Ultra-faint Satellites Grus II, Tucana IV, and Tucana V
Bechtol, K.; Smith, M.; Lidman, C. +55 more
We present Magellan/IMACS spectroscopy of three recently discovered ultra-faint Milky Way satellites, Grus II, Tucana IV, and Tucana V. We measure systemic velocities of Vhel = 110.0 ± 0.5 km s-1, Vhel = 15.9-1.7+1.8 km s-1, and Vhel=-36.2-2.2+2.5 km…
Constraining the Milky Way Mass Profile with Phase-space Distribution of Satellite Galaxies
Li, Ting S.; Wang, Wenting; Han, Jiaxin +3 more
We estimate the Milky Way (MW) halo properties using satellite kinematic data including the latest measurements from Gaia DR2. With a simulation-based 6D phase-space distribution function (DF) of satellite kinematics, we can infer halo properties efficiently and without bias, and handle the selection function and measurement errors rigorously in t…
On the activity of comets: understanding the gas and dust emission from comet 67/Churyumov-Gerasimenko's south-pole region during perihelion
Blum, J.; Fulle, M.; Gundlach, B.
When comets approach the Sun, their surface is heated and the volatile species start to sublimate. Due to the increasing gas pressure, dust is ejected off the surface, which can be observed as cometary coma, dust tail, and trail. However, the underlying physical processes are not fully understood. Using state-of-the-art results for the transport o…
The GALAH survey: chemodynamics of the solar neighbourhood
Ting, Yuan-Sen; Buder, Sven; Bland-Hawthorn, Joss +15 more
We present the chemodynamic structure of the solar neighbourhood using 55 652 stars within a 500 pc volume around the Sun observed by GALAH and with astrometric parameters from Gaia DR2. We measure the velocity dispersion for all three components (vertical, radial, and tangential) and find that it varies smoothly with [Fe/H] and [α/Fe] for each co…
The messy merger of a large satellite and a Milky Way-like galaxy
Helmi, Amina; Koppelman, Helmer H.; Bos, Roy O. Y.
Aims: About 10 billion years ago the Milky Way merged with a massive satellite, Gaia-Enceladus. To gain insight into the properties of its debris we analyse in detail a suite of simulations that includes an experiment that produces a good match to the kinematics of nearby halo stars inferred from Gaia data.
Methods: We compare the kinema…
The Pristine survey - IX. CFHT ESPaDOnS spectroscopic analysis of 115 bright metal-poor candidate stars
Sestito, Federico; Navarro, Julio F.; Martin, Nicolas +18 more
A chemo-dynamical analysis of 115 metal-poor candidate stars selected from the narrow-band Pristine photometric survey is presented based on CFHT high-resolution ESPaDOnS spectroscopy. We have discovered 28 new bright (V < 15) stars with [Fe/H] < -2.5 and 5 with [Fe/H] < -3.0 for success rates of 40 (28/70) and 19 per cent (5/27), respect…
Globular clusters in the Sagittarius stream. Revising members and candidates with Gaia DR2
Bellazzini, M.; Famaey, B.; Malhan, K. +3 more
We reconsider the case for the association of Galactic globular clusters to the tidal stream of the Sagittarius dwarf spheroidal galaxy (Sgr dSph) using Gaia DR2 data. We used RR Lyrae variables to trace the stream in 6D and we selected clusters matching the observed stream in position and velocity. In addition to the clusters residing in the main…
Evidence for a high mutual inclination between the cold Jupiter and transiting super Earth orbiting π Men
Wyatt, Mark C.; Xuan, Jerry W.
π Men hosts a transiting super Earth (P ≈ 6.27 d, m ≈ 4.82 M⊕, R ≈ 2.04 R⊕) discovered by TESS and a cold Jupiter (P ≈ 2093 d, msin I ≈ 10.02 MJup, e ≈ 0.64) discovered from radial velocity. We use Gaia DR2 and Hipparcos astrometry to derive the star's velocity caused by the orbiting planets and constrain the cold …
HD 213885b: a transiting 1-d-period super-Earth with an Earth-like composition around a bright (V = 7.9) star unveiled by TESS
Henning, Thomas; Law, Nicholas M.; Jordán, Andrés +60 more
We report the discovery of the 1.008-d, ultrashort period (USP) super-Earth HD 213885b (TOI-141b) orbiting the bright (V = 7.9) star HD 213885 (TOI-141, TIC 403224672), detected using photometry from the recently launched TESS mission. Using FEROS, HARPS, and CORALIE radial velocities, we measure a precise mass of 8.8 ± 0.6 M⊕ for this …
TESS Spots a Hot Jupiter with an Inner Transiting Neptune
Torres, Guillermo; Vanderburg, Andrew; Latham, David W. +48 more
Hot Jupiters are rarely accompanied by other planets within a factor of a few in orbital distance. Previously, only two such systems have been found. Here, we report the discovery of a third system using data from the Transiting Exoplanet Survey Satellite (TESS). The host star, TOI-1130, is an eleventh magnitude K-dwarf in Gaia G-band. It has two …