ORCID Profile
0000-0002-9428-8732
Current Organisation
University of Rome Tor Vergata
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Publisher: Oxford University Press (OUP)
Date: 25-07-2014
Publisher: Oxford University Press (OUP)
Date: 10-2013
Publisher: American Astronomical Society
Date: 17-08-2010
Publisher: EDP Sciences
Date: 05-2013
Publisher: American Astronomical Society
Date: 28-04-2015
Publisher: American Astronomical Society
Date: 07-10-2010
Publisher: American Astronomical Society
Date: 02-02-2017
Publisher: American Astronomical Society
Date: 16-10-2015
Publisher: EDP Sciences
Date: 10-2013
Publisher: American Astronomical Society
Date: 13-08-2012
Publisher: Oxford University Press (OUP)
Date: 22-11-2018
Publisher: Springer Science and Business Media LLC
Date: 09-01-2023
DOI: 10.1038/S41586-022-05677-Y
Abstract: Transmission spectroscopy 1–3 of exoplanets has revealed signatures of water vapour, aerosols and alkali metals in a few dozen exoplanet atmospheres 4,5 . However, these previous inferences with the Hubble and Spitzer Space Telescopes were hindered by the observations’ relatively narrow wavelength range and spectral resolving power, which precluded the unambiguous identification of other chemical species—in particular the primary carbon-bearing molecules 6,7 . Here we report a broad-wavelength 0.5–5.5 µm atmospheric transmission spectrum of WASP-39b 8 , a 1,200 K, roughly Saturn-mass, Jupiter-radius exoplanet, measured with the JWST NIRSpec’s PRISM mode 9 as part of the JWST Transiting Exoplanet Community Early Release Science Team Program 10–12 . We robustly detect several chemical species at high significance, including Na (19 σ ), H 2 O (33 σ ), CO 2 (28 σ ) and CO (7 σ ). The non-detection of CH 4 , combined with a strong CO 2 feature, favours atmospheric models with a super-solar atmospheric metallicity. An unanticipated absorption feature at 4 µm is best explained by SO 2 (2.7 σ ), which could be a tracer of atmospheric photochemistry. These observations demonstrate JWST’s sensitivity to a rich ersity of exoplanet compositions and chemical processes.
Publisher: American Astronomical Society
Date: 02-2012
Publisher: EDP Sciences
Date: 08-2015
Publisher: Oxford University Press (OUP)
Date: 29-01-2019
DOI: 10.1093/MNRAS/STZ306
Publisher: American Astronomical Society
Date: 22-01-2021
Publisher: American Astronomical Society
Date: 23-05-2016
Publisher: Oxford University Press (OUP)
Date: 12-06-2015
Publisher: American Astronomical Society
Date: 11-02-2022
Abstract: The relative rarity of giant planets around low-mass stars compared with solar-type stars is a key prediction from the core-accretion planet formation theory. In this paper we report on the discovery of four gas giant planets that transit low-mass late K and early M dwarfs. The planets HATS-74Ab (TOI 737b), HATS-75b (TOI 552b), HATS-76b (TOI 555b), and HATS-77b (TOI 730b) were all discovered from the HATSouth photometric survey and follow-up using TESS and other photometric facilities. We use the new ESPRESSO facility at the VLT to confirm systems and measure their masses. We find that these planets have masses of 1.46 ± 0.14 M J, 0.491 ± 0.039 M J, 2.629 ± 0.089 M J, and 1.374 − 0.074 + 0.100 M J, respectively, and radii of 1.032 ± 0.021 R J, 0.884 ± 0.013 R J, 1.079 ± 0.031 R J, and 1.165 ± 0.021 R J, respectively. The planets all orbit close to their host stars with orbital periods ranging from 1.7319 days to 3.0876 days. With further work, we aim to test core-accretion theory by using these and further discoveries to quantify the occurrence rate of giant planets around low-mass host stars.
Publisher: American Astronomical Society
Date: 20-10-2016
Publisher: American Astronomical Society
Date: 21-09-2016
Publisher: American Astronomical Society
Date: 07-11-2016
Publisher: American Astronomical Society
Date: 06-07-2012
Publisher: American Astronomical Society
Date: 18-05-2020
Publisher: EDP Sciences
Date: 07-2010
Publisher: IOP Publishing
Date: 10-06-2016
Publisher: American Astronomical Society
Date: 31-07-2012
Publisher: American Astronomical Society
Date: 27-04-2015
Publisher: American Astronomical Society
Date: 02-01-2019
Publisher: EDP Sciences
Date: 12-04-2011
Publisher: IOP Publishing
Date: 02-2013
DOI: 10.1086/669529
Publisher: American Astronomical Society
Date: 29-08-2016
Publisher: American Astronomical Society
Date: 17-07-2015
Publisher: American Astronomical Society
Date: 21-11-2012
Publisher: Oxford University Press (OUP)
Date: 02-07-2012
Publisher: EDP Sciences
Date: 25-06-2013
Publisher: American Astronomical Society
Date: 07-07-2015
Publisher: IOP Publishing
Date: 25-10-2016
Publisher: American Astronomical Society
Date: 27-01-2014
Publisher: American Astronomical Society
Date: 16-07-2019
Publisher: Oxford University Press (OUP)
Date: 10-07-2019
Abstract: We present the analysis of the event OGLE-2017-BLG-1186 from the 2017 Spitzer microlensing c aign. This is a remarkable microlensing event because its source is photometrically bright and variable, which makes it possible to perform an asteroseismic analysis using ground-based data. We find that the source star is an oscillating red giant with average time-scale of ∼9 d. The asteroseismic analysis also provides us source properties including the source angular size (∼27 $\\mu$as) and distance (∼11.5 kpc), which are essential for inferring the properties of the lens. When fitting the light curve, we test the feasibility of Gaussian processes (GPs) in handling the correlated noise caused by the variable source. We find that the parameters from the GP model are generally more loosely constrained than those from the traditional χ2 minimization method. We note that this event is the first microlensing system for which asteroseismology and GPs have been used to account for the variable source. With both finite-source effect and microlens parallax measured, we find that the lens is likely a ∼0.045 M⊙ brown dwarf at distance ∼9.0 kpc, or a ∼0.073 M⊙ ultracool dwarf at distance ∼9.8 kpc. Combining the estimated lens properties with a Bayesian analysis using a Galactic model, we find a $\\sim 35{{\\ \\rm per\\ cent}}$ probability for the lens to be a bulge object and $\\sim 65{{\\ \\rm per\\ cent}}$ to be a background disc object.
Publisher: American Astronomical Society
Date: 08-03-2016
Publisher: American Astronomical Society
Date: 07-05-2020
Publisher: EDP Sciences
Date: 25-10-2012
Publisher: Oxford University Press (OUP)
Date: 11-2013
Publisher: Oxford University Press (OUP)
Date: 29-01-2019
DOI: 10.1093/MNRAS/STZ283
Publisher: American Astronomical Society
Date: 12-10-2011
Publisher: American Astronomical Society
Date: 02-03-2016
Publisher: American Astronomical Society
Date: 22-03-2016
Publisher: American Astronomical Society
Date: 23-04-2013
Publisher: American Astronomical Society
Date: 28-06-2016
Publisher: American Astronomical Society
Date: 14-11-2012
Publisher: EDP Sciences
Date: 27-03-2013
Publisher: American Astronomical Society
Date: 27-11-2013
Publisher: American Astronomical Society
Date: 28-01-2011
Publisher: Oxford University Press (OUP)
Date: 28-02-2017
DOI: 10.1093/MNRAS/STX500
Publisher: American Astronomical Society
Date: 27-09-2013
Publisher: American Astronomical Society
Date: 17-01-2013
Publisher: American Astronomical Society
Date: 06-05-2013
Publisher: American Astronomical Society
Date: 18-10-2018
Publisher: American Astronomical Society
Date: 27-10-2020
Publisher: American Astronomical Society
Date: 07-2022
Abstract: We report the first unambiguous detection and mass measurement of an isolated stellar-mass black hole (BH). We used the Hubble Space Telescope (HST) to carry out precise astrometry of the source star of the long-duration ( t E ≃ 270 days), high-magnification microlensing event MOA-2011-BLG-191/OGLE-2011-BLG-0462 (hereafter designated as MOA-11-191/OGLE-11-462), in the direction of the Galactic bulge. HST imaging, conducted at eight epochs over an interval of 6 yr, reveals a clear relativistic astrometric deflection of the background star’s apparent position. Ground-based photometry of MOA-11-191/OGLE-11-462 shows a parallactic signature of the effect of Earth’s motion on the microlensing light curve. Combining the HST astrometry with the ground-based light curve and the derived parallax, we obtain a lens mass of 7.1 ± 1.3 M ⊙ and a distance of 1.58 ± 0.18 kpc. We show that the lens emits no detectable light, which, along with having a mass higher than is possible for a white dwarf or neutron star, confirms its BH nature. Our analysis also provides an absolute proper motion for the BH. The proper motion is offset from the mean motion of Galactic disk stars at similar distances by an amount corresponding to a transverse space velocity of ∼45 km s −1 , suggesting that the BH received a “natal kick” from its supernova explosion. Previous mass determinations for stellar-mass BHs have come from radial velocity measurements of Galactic X-ray binaries and from gravitational radiation emitted by merging BHs in binary systems in external galaxies. Our mass measurement is the first for an isolated stellar-mass BH using any technique.
Publisher: American Astronomical Society
Date: 04-11-2015
Publisher: American Astronomical Society
Date: 26-03-2020
Publisher: American Astronomical Society
Date: 15-02-2018
Publisher: American Astronomical Society
Date: 18-01-2019
Publisher: American Astronomical Society
Date: 02-05-2012
Publisher: American Astronomical Society
Date: 26-06-2014
Publisher: American Astronomical Society
Date: 06-05-0011
Publisher: American Astronomical Society
Date: 23-07-2020
Publisher: American Astronomical Society
Date: 29-06-2023
Abstract: Atmospheric mass loss plays a major role in the evolution of exoplanets. This process is driven by the stellar high-energy irradiation, especially in the first hundreds of millions of years after dissipation of the proto-planetary disk. A major source of uncertainty in modeling atmospheric photoevaporation and photochemistry is due to the lack of direct measurements of the stellar flux at extreme-UV (EUV) wavelengths. Several empirical relationships have been proposed in the past to link EUV fluxes to emission levels in X-rays, but the stellar s les employed for this aim are heterogeneous, and the available scaling laws provide significantly different predictions, especially for very active stars. We present new far-UV and X-ray observations of V1298 Tau with Hubble Space Telescope/Cosmic Origins Spectrograph and XMM-Newton, aimed to determine more accurately the high-energy emission of this solar-mass pre-main-sequence star, which hosts four exoplanets. Spectroscopic data were employed to derive the plasma emission measure distribution versus temperature, from the chromosphere to the corona, and the possible variability of this irradiation on short and year-long timescales, due to magnetic activity. As a side result, we have also measured the chemical abundances of several elements in the outer atmosphere of V1298 Tau. We employ our results as a new benchmark point for the calibration of the X-ray to EUV scaling laws, and hence to predict the time evolution of the irradiation in the EUV band, and its effect on the evaporation of exo-atmospheres.
Publisher: American Astronomical Society
Date: 22-01-2018
Publisher: American Astronomical Society
Date: 13-02-2018
Publisher: American Astronomical Society
Date: 05-2023
Abstract: Carbon monoxide (CO) is predicted to be the dominant carbon-bearing molecule in giant planet atmospheres and, along with water, is important for discerning the oxygen and therefore carbon-to-oxygen ratio of these planets. The fundamental absorption mode of CO has a broad, double-branched structure composed of many in idual absorption lines from 4.3 to 5.1 μ m, which can now be spectroscopically measured with JWST. Here we present a technique for detecting the rotational sub-band structure of CO at medium resolution with the NIRSpec G395H instrument. We use a single transit observation of the hot Jupiter WASP-39b from the JWST Transiting Exoplanet Community Early Release Science (JTEC ERS) program at the native resolution of the instrument ( R ∼ 2700) to resolve the CO absorption structure. We robustly detect absorption by CO, with an increase in transit depth of 264 ± 68 ppm, in agreement with the predicted CO contribution from the best-fit model at low resolution. This detection confirms our theoretical expectations that CO is the dominant carbon-bearing molecule in WASP-39b’s atmosphere and further supports the conclusions of low C/O and supersolar metallicities presented in the JTEC ERS papers for WASP-39b.
Publisher: American Astronomical Society
Date: 04-10-2016
Publisher: Oxford University Press (OUP)
Date: 20-03-2018
DOI: 10.1093/MNRAS/STY726
Publisher: American Astronomical Society
Date: 08-01-2013
Publisher: Oxford University Press (OUP)
Date: 09-12-2016
No related grants have been discovered for Luigi Mancini.