Search Publications
The Formation and Evolution of Galactic Disks with APOGEE and the Gaia Survey
Zhao, Gang; Li, Chengdong; Zhai, Meng +1 more
We explore the structure and evolutionary history of Galactic disks with Apache Point Observatory Galactic Evolution Experiment data release 13 (DR13 hereafter) and Gaia Tycho-Gaia Astrometric Solution data. We use the [α/M] ratio to allocate stars into particular Galactic components to elucidate the chemical and dynamical properties of the thin a…
IC 4499 revised: Spectro-photometric evidence of small light-element variations
Dalessandro, E.; Salaris, M.; Bastian, N. +6 more
It has been suggested that IC 4499 is one of the very few old globulars to not host multiple populations with light-element variations. To follow-up on this very interesting result, here we have made use of accurate HST photometry and FLAMES at VLT high-resolution spectroscopy to investigate in more detail the stellar population properties of this…
Fine Resolution Epithermal Neutron Detector (FREND) Onboard the ExoMars Trace Gas Orbiter
Mitrofanov, I.; Zelenyi, L. M.; Malakhov, A. +23 more
ExoMars is a two-launch mission undertaken by Roscosmos and European Space Agency. Trace Gas Orbiter, a satellite part of the 2016 launch carries the Fine Resolution Neutron Detector instrument as part of its payload. The instrument aims at mapping hydrogen content in the upper meter of Martian soil with spatial resolution between 60 and 200 km di…
S stars and s-process in the Gaia era. I. Stellar parameters and chemical abundances in a sub-sample of S stars with new MARCS model atmospheres
Jorissen, A.; Escorza, A.; Van Winckel, H. +6 more
Context. S stars are transition objects between M-type giants and carbon stars on the asymptotic giant branch (AGB). They are characterized by overabundances of s-process elements. Roughly half of them are enhanced in technetium (Tc), an s-process element with no stable isotope, while the other half lack technetium. This dichotomy arises from the …
Chemical inhomogeneities amongst first population stars in globular clusters. Evidence for He variations
Dalessandro, E.; Salaris, M.; Cabrera-Ziri, I. +3 more
Spreads in light element abundances among stars (also known as multiple populations) are observed in nearly all globular clusters. One way to map such chemical variations using high-precision photometry is to employ a suitable combination of stellar magnitudes in the F275W, F336W, F438W, and F814W filters (called the "chromosome map"), to maximise…
Predicted microlensing events from analysis of Gaia Data Release 2
Bramich, D. M.
Context. Astrometric microlensing can be used to make precise measurements of the masses of lens stars that are independent of their assumed internal physics. Such direct mass measurements, obtained purely by observing the gravitational effects of the stars on external objects, are crucial for validating theoretical stellar models. Specifically, a…
A Cool Core Disturbed: Observational Evidence for the Coexistence of Subsonic Sloshing Gas and Stripped Shock-heated Gas around the Core of RX J1347.5-1145
Kohno, Kotaro; Oguri, Masamune; Iono, Daisuke +13 more
RX J1347.5-1145 (z = 0.451) is one of the most luminous X-ray galaxy clusters; it hosts a prominent cool core and exhibits a signature of a major merger. We present the first direct observational evidence for the subsonic nature of the sloshing motion of the cool core. We find that a residual X-ray image from the Chandra X-ray Observatory after re…
Propagating Spectropolarimetric Disturbances in a Large Sunspot
Erdélyi, R.; Ermolli, I.; Murabito, M. +7 more
We present results derived from the analysis of spectropolarimetric measurements of active region AR12546, which represents one of the largest sunspots to have emerged onto the solar surface over the last 20 years. The region was observed with full-Stokes scans of the Fe I 617.3 nm and Ca II 854.2 nm lines with the Interferometric BIdimensional Sp…
Calibrating the system dynamics of LISA Pathfinder
Mendes, L.; Russano, G.; Lloro, I. +75 more
LISA Pathfinder (LPF) was a European Space Agency mission with the aim to test key technologies for future space-borne gravitational-wave observatories like LISA. The main scientific goal of LPF was to demonstrate measurements of differential acceleration between free-falling test masses at the sub-femto-g level, and to understand the residual acc…
Stellar and Planetary Characterization of the Ross 128 Exoplanetary System from APOGEE Spectra
Cunha, Katia; Smith, Verne V.; Souto, Diogo +14 more
The first detailed chemical abundance analysis of the M-dwarf (M4.0) exoplanet-hosting star Ross 128 is presented here, based upon near-infrared (1.5-1.7 µm), high-resolution (R ∼ 22,500) spectra from the SDSS Apache Point Galactic Evolution Experiment survey. We determined precise atmospheric parameters T eff = 3231 ± 100 K, log …