Search Publications
Testing massive star evolution, star formation history, and feedback at low metallicity. Spectroscopic analysis of OB stars in the SMC Wing
Hamann, W. -R.; Gallagher, J. S.; Oskinova, L. M. +6 more
Stars that start their lives with spectral types O and early B are the progenitors of core-collapse supernovae, long gamma-ray bursts, neutron stars, and black holes. These massive stars are the primary sources of stellar feedback in star-forming galaxies. At low metallicities, the properties of massive stars and their evolution are not yet fully …
A Cooling Anomaly of High-mass White Dwarfs
Cheng, Sihao; Cummings, Jeffrey D.; Ménard, Brice
Recently, the power of Gaia data has revealed an enhancement of high-mass white dwarfs (WDs) on the Hertzsprung-Russell diagram, called the Q branch. This branch is located at the high-mass end of the recently identified crystallization branch. Investigating its properties, we find that the number density and velocity distribution on the Q branch …
A super-Earth and two sub-Neptunes transiting the nearby and quiet M dwarf TOI-270
Vanderburg, Andrew; Latham, David W.; Quinn, Samuel N. +57 more
One of the primary goals of exoplanetary science is to detect small, temperate planets passing (transiting) in front of bright and quiet host stars. This enables the characterization of planetary sizes, orbits, bulk compositions, atmospheres and formation histories. These studies are facilitated by small and cool M dwarf host stars. Here we report…
Constraining the Milky Way halo potential with the GD-1 stellar stream
Malhan, Khyati; Ibata, Rodrigo A.
We use ESA/Gaia astrometry together with SEGUE and LAMOST measurements of the GD-1 stellar stream to explore the improvement on the Galactic gravitational potential that these new data provide. Assuming a realistic universal model for the dark matter halo together with reasonable models of the baryonic components, we find that the orbital solution…
Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS). II. A broadened sodium feature on the ultra-hot giant WASP-76b
Heng, K.; Ségransan, D.; Deline, A. +18 more
High-resolution optical spectroscopy is a powerful tool to characterise exoplanetary atmospheres from the ground. The sodium D lines, with their large cross sections, are especially suited to studying the upper layers of atmospheres in this context. We report on the results from Hot Exoplanet Atmosphere Resolved with Transit Spectroscopy survey (H…
Gaia Data Release 2. Cross-match with external catalogues: algorithms and results
Marinoni, S.; Marrese, P. M.; Altavilla, G. +1 more
Context. Although the Gaia catalogue on its own is a very powerful tool, it is the combination of this high-accuracy archive with other archives that will truly open up amazing possibilities for astronomical research. The advanced interoperation of archives is based on cross-matching, leaving the user with the feeling of working with one single da…
X-Ray Properties of SPT-selected Galaxy Clusters at 0.2 < z < 1.5 Observed with XMM-Newton
Miller, Eric D.; Schrabback, Tim; Holzapfel, W. L. +22 more
We present measurements of the X-ray observables of the intracluster medium (ICM), including luminosity L X , ICM mass M ICM, emission-weighted mean temperature T X , and integrated pressure Y X , that are derived from XMM-Newton X-ray observations of a Sunyaev-Zel’dovich effect (SZE) selected sample …
Hunting for open clusters in Gaia DR2: the Galactic anticentre
Castro-Ginard, A.; Jordi, C.; Luri, X. +2 more
Context. The Gaia Data Release 2 (DR2) provided an unprecedented volume of precise astrometric and excellent photometric data. In terms of data mining the Gaia catalogue, machine learning methods have shown to be a powerful tool, for instance in the search for unknown stellar structures. Particularly, supervised and unsupervised learning methods c…
Toward Precise Stellar Ages: Combining Isochrone Fitting with Empirical Gyrochronology
Hogg, David W.; Angus, Ruth; Morton, Timothy D. +7 more
We present a new age-dating technique that combines gyrochronology with isochrone fitting to infer ages for FGKM main-sequence and subgiant field stars. Gyrochronology and isochrone fitting are each capable of providing relatively precise ages for field stars in certain areas of the Hertzsprung-Russell diagram (HRD): gyrochronology works optimally…
He I λ 10 830 Å in the transmission spectrum of HD209458 b
Schmitt, J. H. M. M.; Alonso-Floriano, F. J.; Sánchez-López, A. +27 more
Context. Recently, the He I triplet at 10 830 Å was rediscovered as an excellent probe of the extended and possibly evaporating atmospheres of close-in transiting planets. This has already resulted in detections of this triplet in the atmospheres of a handful of planets, both from space and from the ground. However, while a strong signal is expect…