A5086323221- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Solar and Space Plasma Dynamics
- Molecular Spectroscopy and Structure
- Radio Astronomy Observations and Technology
- Spectroscopy and Laser Applications
- Space Exploration and Technology
- Dark Matter and Cosmic Phenomena
- Adaptive optics and wavefront sensing
- Superconducting Materials and Applications
- Radical Photochemical Reactions
- Particle Accelerators and Free-Electron Lasers
- Computational Physics and Python Applications
- Systemic Lupus Erythematosus Research
- Cardiac Valve Diseases and Treatments
- Galaxies: Formation, Evolution, Phenomena
- Pulsars and Gravitational Waves Research
- Geophysics and Gravity Measurements
- Fluorine in Organic Chemistry
Osservatorio Astrofisico di Catania
2015-2024
European Organization for Nuclear Research
2024
Space Telescope Science Institute
2023
Columbia University
2020-2022
National Institute for Astrophysics
2006-2021
Icahn School of Medicine at Mount Sinai
2011-2018
City University of New York
2018
Children's Hospital of Philadelphia
2017
Universidad Complutense de Madrid
2009
Université de Strasbourg
2009
The mass accretion rate, Ṁacc, is a key quantity for the understanding of physical processes governing evolution discs around young low-mass (M⋆ ≲ 2.0 M⊙) stars and substellar objects (YSOs). We present here results study stellar properties (almost) complete sample class II transitional YSOs in Lupus I, II, III IV clouds, based on spectroscopic data acquired with VLT/X-shooter spectrograph. Our combines dataset from our previous work new observations 55 additional objects. have investigated...
We present X-Shooter/VLT observations of a sample 36 accreting low-mass stellar and sub-stellar objects (YSOs) in the Lupus star forming region, spanning range mass from ~0.03 to ~1.2Msun, but mostly with 0.1Msun < Mstar 0.5Msun. Our aim is twofold: firstly, analyse relationship between excess-continuum line emission accretion diagnostics, and, secondly, investigate properties terms physical central object. The luminosity (Lacc), it rate (Macc), derived by modelling excess emission, UV...
We present results of a long-baseline interferometry campaign using the PAVO beam combiner at CHARA Array to measure angular sizes five main-sequence stars, one subgiant and four red giant stars for which solar-like oscillations have been detected by either Kepler or CoRoT. By combining interferometric diameters, Hipparcos parallaxes, asteroseismic densities, bolometric fluxes, high-resolution spectroscopy, we derive full set near-model-independent fundamental properties sample. first use...
The Gaia-ESO Survey is obtaining high-quality spectroscopic data for about 10^5 stars using FLAMES at the VLT. UVES high-resolution spectra are being collected 5000 FGK-type stars. These analyzed in parallel by several state-of-the-art methodologies. Our aim to present how these analyses were implemented, discuss their results, and describe a final recommended parameter scale defined. We also precision (method-to-method dispersion) accuracy (biases with respect reference values) of...
In the last 15 years different ground-based spectroscopic surveys have been started (and completed) with general aim of delivering stellar parameters and elemental abundances for large samples Galactic stars, complementing Gaia astrometry. Among those surveys, Gaia-ESO Public Spectroscopic Survey (GES), only one performed on a 8m class telescope, was designed to target 100,000 stars using FLAMES ESO VLT (both Giraffe UVES spectrographs), covering all Milky Way populations, special focus open...
Context. The Gaia-ESO Public Spectroscopic Survey is an ambitious project designed to obtain astrophysical parameters and elemental abundances for 100 000 stars, including large representative samples of the stellar populations in Galaxy, a well-defined sample 60 (plus 20 archive) open clusters. We provide internally consistent results calibrated on benchmark stars star clusters, extending across very wide range ages. This provides legacy data set intrinsic value, equally wide-ranging...
The primary science goal of the Kepler Mission is to provide a census exoplanets in solar neighborhood, including identification and characterization habitable Earth-like planets. asteroseismic capabilities mission are being used determine precise radii ages for target stars from their solar-like oscillations. Chaplin et al. (2010) published observations three bright G-type stars, which were monitored during first 33.5 days operations. One these subgiant KIC 11026764, exhibits characteristic...
The nearly continuous light curves with micromagnitude precision provided by the space mission Kepler are revolutionising our view of pulsating stars. They have revealed a vast sea low-amplitude pulsation modes that were undetectable from Earth. long time base allows an accurate determination frequencies and amplitudes needed for in-depth asteroseismic modeling. However, study to be successful, first estimates stellar parameters need known they can not derived photometry itself. Input...
Context. A key science goal of the Gaia-ESO survey (GES) at VLT is to use kinematics low-mass stars in young clusters and star forming regions probe their dynamical histories how they populate field as become unbound. The clustering around massive Wolf-Rayet binary system γ2 Velorum was one first GES targets.
ABSTRACT Host star metallicity provides a measure of the conditions in protoplanetary disks at time planet formation. Using sample over 20,000 Kepler stars with spectroscopic metallicities from LAMOST survey, we explore how exoplanet population depends on host as function orbital period and size. We find that exoplanets periods less than 10 days are preferentially found around metal-rich ([Fe/H] ≃ 0.15 ± 0.05 dex). The occurrence rates these hot increases to ∼30% for super-solar ∼10%...
The LAMOST-Kepler survey, whose spectra are analyzed in the present paper, is first large spectroscopic project aimed at characterizing these sources. Our work focused selecting emission-line objects and chromospherically active stars on evaluation of atmospheric parameters. We have used a version code ROTFIT that exploits wide homogeneous collection real star spectra, i.e. Indo US library. provide catalog with parameters (Teff, logg, [Fe/H]), radial velocity (RV) an estimate projected...
Abstract Superflares are large explosive events on stellar surfaces one to six orders-of-magnitude larger than the largest flares observed Sun throughout space age. Due huge amount of energy released in these superflares, it has been speculated if underlying mechanism is same as for solar flares, which caused by magnetic reconnection corona. Here, we analyse observations made with LAMOST telescope 5,648 solar-like stars, including 48 superflare stars. These show that stars generally...
The radial metallicity distribution in the Galactic thin disc represents a crucial constraint for modelling formation and evolution. Open clusters allow us to derive both its evolution over time. In this paper we perform first investigation of present-day based on [Fe/H] determinations late type members pre-main-sequence clusters. Because their youth, these are therefore essential tracing current inter-stellar medium metallicity. We used products Gaia-ESO Survey analysis 12 young regions...
We present an empirical model of age-dependent photospheric lithium depletion, calibrated using a large, homogeneously-analysed sample 6200 stars in 52 open clusters, with ages from 2--6000 Myr and $-0.3<{\rm [Fe/H}]<0.2$, observed the Gaia-ESO spectroscopic survey. The is used to obtain age estimates posterior probability distributions measurements Li I 6708A equivalent width for individual (pre) main sequence $3000 < T_{\rm eff}/{\rm K} <6500$, domain where determination HR diagram either...
Abstract JWST has ushered in an era of unprecedented ability to characterize exoplanetary atmospheres. While there are over 5000 confirmed planets, more than 4000 Transiting Exoplanet Survey Satellite (TESS) planet candidates still unconfirmed and many the best planets for atmospheric characterization may remain be identified. We present a sample TESS that we identify as “best-in-class” transmission emission spectroscopy with JWST. These targets sorted into bins across equilibrium...
We present UBVRI light curves of BL Lacertae from May 2000 to January 2001, obtained by 24 telescopes in 11 countries. More than 15000 observations were performed that period, which was the extension Whole Earth Blazar Telescope (WEBT) campaign originally planned for July-August 2000. Rapid flux oscillations are all time, involving variations up a few tenths mag on hour time scales, and witnessing an intense intraday activity this source. Colour indexes have been derived coupling highest...
The radio quasar 3C 454.3 underwent an exceptional optical outburst lasting more than 1 year and culminating in spring 2005. maximum brightness detected was R = 12.0, which represents the most luminous state thus far observed (M_B ~ -31.4). In order to follow emission behaviour of source detail, a large multiwavelength campaign organized by Whole Earth Blazar Telescope (WEBT). Continuous optical, near-IR monitoring performed several bands. ToO pointings Chandra INTEGRAL satellites provided...
Context. The quasar 3C 279 is among the most extreme blazars in terms of luminosity and variability flux at all wavebands. Its variations polarization are quite complex therefore require intensive monitoring observations multiple wavebands to characterise interpret observed changes.
Aims. Since the CGRO operation in 1991–2000, one of primary unresolved questions about blazar γ-ray emission has been its possible correlation with low-energy (in particular optical) emission. To help answer this problem, Whole Earth Blazar Telescope (WEBT) consortium organized GLAST-AGILE Support Program (GASP) to provide optical-to-radio monitoring data be compared detections by AGILE and GLAST satellites. This new WEBT project started early September 2007, just before a strong detection...
The asteroseismic and planetary studies, like all research related to stars, need precise accurate stellar atmospheric parameters as input. We aim at deriving the effective temperature (Teff), surface gravity (log g), metallicity ([Fe/H]), projected rotational velocity (v sin i) MK type for 169 F-, G-, K- M-type Kepler targets which were observed spectroscopically from ground with five different instruments. use two spectroscopic methods analyse 189 high-resolution, high-signal-to-noise...
The discovery of lithium-rich giants contradicts expectations from canonical stellar evolution. Here we report on the serendipitous 20 Li-rich observed during Gaia-ESO Survey, which includes first nine giant stars known towards CoRoT fields. Most our have near-solar metallicities and parameters consistent with being before luminosity bump. This is difficult to reconcile deep mixing models proposed explain lithium enrichment, because these can only operate at later evolutionary stages: or...