Context.
Ultra-hot Jupiters (UHJs), rendering the hottest planetary atmospheres, offer great opportunities of detailed characterisation with high-resolution spectroscopy. MASCARA-4 b is a recently ...discovered close-in gas giant belonging to this category.
Aims.
We aim to characterise MASCARA-4 b, search for chemical species in its atmosphere, and put these in the context of the growing knowledge on the atmospheric properties of UHJs.
Methods.
In order to refine system and planet parameters, we carried out radial velocity measurements and transit photometry with the CORALIE spectrograph and EulerCam at the Swiss 1.2 m Euler telescope. We observed two transits of MASCARA-4 b with the high-resolution spectrograph ESPRESSO at ESO’s Very Large Telescope. We searched for atomic, ionic, and molecular species via individual absorption lines and cross-correlation techniques. These results are compared to literature studies on UHJs characterised to date.
Results.
With CORALIE and EulerCam observations, we update the mass of MASCARA-4 b (
M
p
= 1.675 ± 0.241
M
Jup
) as well as other system and planet parameters. In the transmission spectrum derived from ESPRESSO observations, we resolve excess absorption by H
α
, H
β
, NaI D1&D2, CaII H&K, and a few strong lines of MgI, FeI, and FeII. We also present the cross-correlation detection of Mg I, CaI, Cr I, Fe I, and Fe II. The absorption strength of Fe II significantly exceeds the prediction from a hydrostatic atmospheric model, as commonly observed in other UHJs. We attribute this to the presence of Fe II in the exosphere due to hydrodynamic outflows. This is further supported by the positive correlation of absorption strengths of Fe II with the Hα line, which is expected to probe the extended upper atmosphere and the mass loss process. Comparing transmission signatures of various species in the UHJ population allows us to disentangle the hydrostatic regime (as traced via the absorption by Mg I and Fe I) from the exospheres (as probed by Hα and Fe II) of the strongly irradiated atmospheres.
Context.
The spectrograph ESPRESSO recently obtained a limit on the variation of the fine-structure constant,
α
, through measurements along the line of sight of a bright quasar with a precision of ...1.36 ppm at 1
σ
level. This imposes new constraints on cosmological models with a varying
α
. We assume such a model where the electromagnetic sector is coupled to a scalar field dark energy responsible for the current acceleration of the Universe. We parametrise the variation of
α
with two extra parameters, one defining the cosmological evolution of the quintessence component and the other fixing the coupling with the electromagnetic field.
Aims.
The objective of this work is to constrain these parameters with both astrophysical and local probes. We also carried out a comparative analysis of how each data probe may constrain our parametrisation.
Methods.
We performed a Bayesian analysis by comparing the predictions of the model with observations. The astrophysical datasets are composed of quasar spectra measurements, including the latest ESPRESSO data point, as well as
Planck
observations of the cosmic microwave background. We combined these with local results from atomic clocks and the MICROSCOPE experiment.
Results.
The constraints placed on the quintessence parameter are consistent with a null variation of the field, and are therefore compatible with a ΛCDM cosmology. The constraints on the coupling to the electromagnetic sector are dominated by the Eötvös parameter local bound.
Conclusions.
More precise measurements with ESPRESSO will be extremely important to study the cosmological evolution of
α
as it probes an interval of redshift not accessible to other types of observations. However, for this particular model, current available data favour a null variation of
α
resulting mostly from the strong MICROSCOPE limits.
Ultra-hot Jupiters (UHJs), rendering the hottest planetary atmospheres, offer great opportunities of detailed characterisation with high-resolution spectroscopy. MASCARA-4 b is a recently discovered ...close-in gas giant belonging to this category. In order to refine system and planet parameters, we carried out radial velocity measurements and transit photometry with the CORALIE spectrograph and EulerCam at the Swiss 1.2m Euler telescope. We observed two transits of MASCARA-4 b with the high-resolution spectrograph ESPRESSO at ESO's Very Large Telescope. We searched for atomic, ionic, and molecular species via individual absorption lines and cross-correlation techniques. These results are compared to literature studies on UHJs characterised to date. With CORALIE and EulerCam observations, we updated the mass of MASCARA-4 b (1.675 +/- 0.241 Jupiter masses) as well as other system and planet parameters. In the transmission spectrum derived from ESPRESSO observations, we resolve excess absorption by H\(\alpha\), H\(\beta\), Na D1 & D2, Ca+ H & K, and a few strong individual lines of Mg, Fe and Fe+. We also present the cross-correlation detection of Mg, Ca, Cr, Fe and Fe+. The absorption strength of Fe+ significantly exceeds the prediction from a hydrostatic atmospheric model, as commonly observed in other UHJs. We attribute this to the presence of Fe+ in the exosphere due to hydrodynamic outflows. This is further supported by the positive correlation of absorption strengths of Fe+ with the H\(\alpha\) line. Comparing transmission signatures of various species in the UHJ population allows us to disentangle the hydrostatic regime (as traced via the absorption by Mg and Fe) from the exospheres (as probed by H\(\alpha\) and Fe+) of the strongly irradiated atmospheres.
M-dwarfs are the most abundant stars in the galaxy and popular targets for exoplanet searches. However, their intrinsic faintness and complex spectra inhibit precise characterisation. We only know of ...dozens of M-dwarfs with fundamental parameters of mass, radius and effective temperature characterised to better than a few per cent. Eclipsing binaries remain the most robust means of stellar characterisation. Here we present two targets from the Eclipsing Binary Low Mass (EBLM) survey that were observed with K2: EBLM J0055-00 and EBLM J2217-04. Combined with HARPS and CORALIE spectroscopy, we measure M-dwarf masses with precisions better than 5%, radii better than 3% and effective temperatures on order 1%. However, our fits require invoking a model to derive parameters for the primary star. By investigating three popular models, we determine that the model uncertainty is of similar magnitude to the statistical uncertainty in the model fits. Therefore, whilst these can be considered benchmark M-dwarfs, we caution the community to consider model uncertainty when pushing the limits of precise stellar characterisation.
The decay of an unstable system is usually described by an exponential law. Quantum mechanics predicts strong deviations of the survival probability from the exponential: Indeed, the decay is ...initially quadratic, while at very large times it follows a power law, with superimposed oscillations. The latter regime is particularly elusive and difficult to observe. Here we employ arrays of single-mode optical waveguides, fabricated by femtosecond laser direct inscription, to implement quantum systems where a discrete state is coupled and can decay into a continuum. The optical modes correspond to distinct quantum states of the photon, and the temporal evolution of the quantum system is mapped into the spatial propagation coordinate. By injecting coherent light states in the fabricated photonic structures and by measuring a small scattered fraction of such light with an unprecedented dynamic range, we are able to experimentally observe not only the exponential decay regime, but also the quadratic Zeno region and the power-law decay at long evolution times.
We present high-precision radial velocities (RVs) from the HARPS-N spectrograph for HD79210 and HD79211, two M0V members of a gravitationally-bound binary system. We detect a planet candidate with a ...period of \(24.421^{+0.016}_{-0.017}\) days around HD79211 in these HARPS-N RVs, validating the planet candidate originally identified in CARMENES RV data alone. Using HARPS-N, CARMENES and HIRES RVs spanning a total of 25 years, we further refine the planet candidate parameters to \(P=24.422\pm0.014\) days, \(K=3.19\pm0.27\) m/s, \(M\) sin \(i = 10.6 \pm 1.2 M_\oplus\), and \(a = 0.142 \pm0.005\) au. We do not find any additional planet candidate signals in the data of HD79211 nor do we find any planet candidate signals in HD79210. This system adds to the number of exoplanets detected in binaries with M dwarf members, and serves as a case study for planet formation in stellar binaries.
We explore the features of an equally-spaced array of two-level quantum emitters, that can be either natural atoms (or molecules) or artificial atoms, coupled to a field with a single continuous ...degree of freedom (such as an electromagnetic mode propagating in a waveguide). We investigate the existence and characteristics of bound states, in which a single excitation is shared among the emitters and the field. We focus on bound states in the continuum, occurring in correspondence of excitation energies in which a single excited emitter would decay. We characterize such bound states for an arbitrary number of emitters, and obtain two main results, both ascribable to the presence of evanescent fields. First, the excitation profile of the emitter states is a sinusoidal wave. Second, we discuss the emergence of multimers, consisting in subsets of emitters separated by two lattice spacings in which the electromagnetic field is approximately vanishing.
In recent years, biochar is being widely considered as an effective and low cost biosorbent in water and wastewater treatment processes. Various biomasses can be effectively used for biochar ...production, and this study investigates the use of a novel biochar derived from pistachio green hull to remove Cu(II) from aqueous solutions. The biochar was analyzed by FTIR, SEM-WDX, and SEM-EDX. The efficacy of several experimental factors was investigated in a number of batch adsorption experiments. The sorption kinetics of copper on the biochar were satisfactorily described by a pseudo–second order model. The adsorption isotherms were well described by the Langmuir model. The analysis of experimental results suggested that the Cu(II) sorption onto biochar could mainly be ascribed to cation exchange, surface precipitation, and surface complexation with oxygen-containing functional groups. Overall, it can be concluded that biochar derived from pistachio green hull is valuable as a green cost-effective sorbent for Cu(II) removal from water.
Display omitted
•Pistachio green hull, an agricultural byproduct, used to produce biochar.•Pistachio derived biochar showed very promising Cu(II) sorption characteristics.•Different sorption mechanisms: ion exchange, precipitation, surface complexation.
Objective To evaluate clinical complications after transperineal prostate biopsy in patients undergoing 12 vs 18 vs more than 24 cores. Methods From February 2002 to December 2012, 3000 patients ...(median age, 66 years) underwent transperineal prostate biopsy after an abnormal result on a digital rectal examination, prostate-specific antigen (PSA) level >10 ng/mL, PSA values between 4.1 and 10, 2.6 and 4, and <2.5 ng/mL with free/total PSA ≤25%, ≤20%, and ≤15%, respectively. Of these, 915 (30.5%), 1330 (48.5%), and 630 patients (21%) underwent 12, 18, and >24 needle cores under antibiotic prophylaxis. Prostate biopsy-related complications were evaluated within 15 to 20 days after the prostate biopsy. The number of patients who needed hospital admission or an emergency department visit (EDV) was recorded. Results Prostate cancer was found in 1150 (38.3%) patients. Side effects after the biopsy occurred in 40.2% of the patients, and the complications were directly correlated with the number of needle cores: 31.5% with 12 cores, 41.8% with 18 cores, and 57.4% with >24 cores ( P = .001). Overall hospital admission and EDV were 1.2% and 9.1% and occurred, respectively, in 1% and 6% (12 cores) vs 1.3% and 9.6% (18 cores) vs 1.6% and 14.4% (>24 cores) of the patients. The most frequent complication that needed hospital admission vs EDV was urinary tract infection (0.7%) vs acute urinary retention (6.7%), respectively. No patients developed sepsis. Conclusion Clinical complications after transperineal prostate biopsy occurred in 40.2% of the patients, but only 1.2% required hospital admission. The number of needle cores (12 vs 18 vs >24) significantly correlated with increased onset of side effects.
The correlation properties of light provide an outstanding tool to overcome the limitations of traditional imaging techniques. A relevant case is represented by correlation plenoptic imaging (CPI), a ...quantum-inspired volumetric imaging protocol employing spatio-temporally correlated photons from either entangled or chaotic sources to address the main limitations of conventional light-field imaging, namely, the poor spatial resolution and the reduced change of perspective for 3D imaging. However, the application potential of high-resolution imaging modalities relying on photon correlations is limited, in practice, by the need to collect a large number of frames. This creates a gap, unacceptable for many relevant tasks, between the time performance of correlated-light imaging and that of traditional imaging methods. In this article, we address this issue by exploiting the photon number correlations intrinsic in chaotic light, combined with a cutting-edge ultrafast sensor made of a large array of single-photon avalanche diodes (SPADs). This combination of source and sensor is embedded within a novel single-lens CPI scheme enabling to acquire 10 volumetric images per second. Our results place correlated-photon imaging at a competitive edge and prove its potential in practical applications.
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