Search Publications
Chemical Abundance Signature of J0023+0307: A Second-generation Main-sequence Star with [Fe/H] < -6
Hansen, Terese T.; Ezzeddine, Rana; Frebel, Anna +4 more
We present a chemical abundance analysis of the faint halo metal-poor main-sequence star J0023+0307, with [Fe/H] < -6.3, based on a high-resolution (R ∼ 35,000) Magellan/MIKE spectrum. The star was originally found to have [Fe/H] < -6.6 based on a Ca II K measurement in an R ∼ 2500 spectrum. No iron lines could be detected in our MIKE spectr…
The bimodal [Mg/Fe] versus [Fe/H] bulge sequence as revealed by APOGEE DR14
Schultheis, M.; Minniti, D.; Recio-Blanco, A. +5 more
Context. The Galactic bulge has a bimodal metallicity distribution function: different kinematic, spatial, and, potentially, age distributions characterize the metal-poor and metal-rich components. Despite this observed dichotomy, which argues for different formation channels for those stars, the distribution of bulge stars in the α-abundance vers…
Magnetic Turbulence Spectra and Intermittency in the Heliosheath and in the Local Interstellar Medium
Pogorelov, Nikolai V.; Fraternale, Federico; Richardson, John D. +1 more
The understanding of inertial-scale dynamics in the heliosheath is not yet thorough. Magnetic field fluctuations across the inner heliosheath (IHS) and the local interstellar medium (LISM) are here considered to provide accurate and highly resolved statistics over different plasma conditions between 88 and 136 au. By using the unique in situ 48 s …
Mutual orbit orientations of transneptunian binaries
Buie, M. W.; Roe, H. G.; Trujillo, C. A. +8 more
We present Keplerian orbit solutions for the mutual orbits of 17 transneptunian binary systems (TNBs). For ten of them, the orbit had not previously been known: 60458 2000 CM114, 119979 2002 WC19, 160091 2000 OL67, 160256 2002 PD149, 469514 2003 QA91, 469705 ǂKá̦gára, 508788 2000 CQ114
The Galactic spiral structure as revealed by O- and early B-type stars
Wang, H. -F.; Huang, Y.; Chen, B. -Q. +7 more
We investigate the morphology and kinematics of the Galactic spiral structure based on a new sample of O- and early B-type stars. We select 6858 highly confident OB star candidates from the combined data of the VST Photometric H α Survey Data Release 2 (VPHAS+ DR2) and the Gaia Data Release 2 (Gaia DR2). Together with the O-B2 stars from the liter…
The Gaia-ESO Survey: asymmetric expansion of the Lagoon Nebula cluster NGC 6530 from GES and Gaia DR2
Gilmore, G.; Bayo, A.; Koposov, S. E. +25 more
The combination of precise radial velocities from multi-object spectroscopy and highly accurate proper motions from Gaia DR2 opens up the possibility for detailed 3D kinematic studies of young star-forming regions and clusters. Here, we perform such an analysis by combining Gaia-ESO Survey spectroscopy with Gaia astrometry for ∼900 members of the …
Aliphatic and aromatic hydrocarbons in comet 67P/Churyumov-Gerasimenko seen by ROSINA
Altwegg, K.; Balsiger, H.; Fuselier, S. A. +10 more
Context. Unlike all previous cometary space missions, the Rosetta spacecraft accompanied its target, comet 67P/Churyumov-Gerasimenko, for more than two years on its way around the Sun. Thereby, an unexpected diversity and complexity of the chemical composition was revealed.
Aims: Our first step of decrypting the exact chemical composition of …
J-PLUS: Identification of low-metallicity stars with artificial neural networks using SPHINX
Caballero, J. A.; Mendes de Oliveira, C.; Beers, T. C. +24 more
Context. We present a new methodology for the estimation of stellar atmospheric parameters from narrow- and intermediate-band photometry of the Javalambre Photometric Local Universe Survey (J-PLUS), and propose a method for target pre-selection of low-metallicity stars for follow-up spectroscopic studies. Photometric metallicity estimates for star…
A dust and gas cavity in the disc around CQ Tau revealed by ALMA
Henning, Thomas; Kwon, Woojin; Testi, Leonardo +23 more
The combination of high-resolution and sensitivity offered by ALMA is revolutionizing our understanding of protoplanetary discs, as their bulk gas and dust distributions can be studied independently. In this paper we present resolved ALMA observations of the continuum emission (λ = 1.3 mm) and CO isotopologues (12CO, 13CO, C<…
Discovery of a Very Hot Phase of the Milky Way Circumgalactic Medium with Non-solar Abundance Ratios
Nicastro, Fabrizio; Mathur, Smita; Das, Sanskriti +1 more
We present the discovery of a very hot gas phase of the Milky Way circumgalactic medium (CGM) at T ≈ 107 K, using deep XMM-Newton Reflection Grating Spectrometer observations of the blazar 1ES 1553+113. The hot gas, coexisting with a warm-hot phase at T ≈ 106 K is α-enhanced, with [{{O}}/{Fe}]={0.9}-0.3+0.7