Explanipedia

Cosmologically viable solutions in geometric modified gravity Open

Paulo Alexandre Gomes Monteiro, C. J. A. P. Martins · 2025

The discovery of the accelerated expansion of the Universe highlighted General Relativity’s inability to naturally account for dark energy without invoking a finely tuned cosmological constant. In response, a wide range of alternative para…

Distinguishing distance duality breaking models using electromagnetic and gravitational waves measurements Open

Chiara De Leo, M. Martinelli, Rocco D’Agostino, Giulia Gianfagna, C. J. A. P. Martins · 2025

Several assumptions at the foundation of the standard cosmological model have as a direct consequence a specific relation between cosmological distances, known as the distance duality relation, whose violation would be a smoking gun of dev…

Unveiling the nature of HE 0107-5240 Open

E. Caffau, M. Steffen, P. Molaro, P. Bonifacio, N. Christlieb , et al. · 2025

The vast majority of the most iron-poor stars in the Galaxy exhibit a strong carbon enhancement, with C/H ratios only about two orders of magnitude below solar. This unusual chemical composition likely reflects the properties of the gas cl…

TOI-283 b: A transiting mini-Neptune in a 17.6-day orbit discovered with TESS and ESPRESSO Open

F. Murgas, E. Pallé, A. Suárez Mascareño, J. Korth, F. J. Pozuelos , et al. · 2025

Context . Super-Earths and mini-Neptunes are missing from our Solar System, yet they appear to be the most abundant planetary types in our Galaxy. A detailed characterization of key planets within this population is important for understan…

CANDI data and settings Open

Chiara Leo, M. Martinelli, Rocco D’Agostino, Giulia Gianfagna, C. J. A. P. Martins · 2025

In this package you will find: Mock data generator – a Jupyter notebook to generate the mock datasets used in the paper arxiv:2505.13613.Note: the cut on GW data is implemented in a simplified (but nearly equivalent) way compared to the me…

TOI-2322: Two transiting rocky planets close to the stellar rotation period and its first harmonic Open

Mélissa J. Hobson, A. Suárez Mascareño, C. Lovis, F. Bouchy, B. Lavie , et al. · 2025

Context . Active regions on the stellar surface can induce quasi-periodic radial velocity (RV) variations that can mimic planets and mask true planetary signals. These spurious signals can be problematic for RV surveys such as those carrie…

MUMIFICAÇÃO FETAL EM CADELAS Open

C. J. A. P. Martins, Djail Santos, Gustavo Rabello dos Anjos, GIULIA SUNINGA OLIVEIRA, Laı́s de Carvalho , et al. · 2025

A mumificação fetal em cadelas ocorre quando um feto morre dentro do útero e não é absorvido ou expelido, resultando em um processo de preservação dos tecidos, semelhantes à mumificação humana. Este processo ocorre geralmente na segunda me…

Varying fundamental constants cosmography Open

C. J. A. P. Martins · 2025

Euclid: Forecasts on $Λ$CDM consistency tests with growth rate data Open

Indira Ocampo, D Sapone, Savvas Nesseris, George Alestas, J García-Bellido , et al. · 2025

The large-scale structure (LSS) of the Universe is an important probe for deviations from the canonical cosmological constant $Λ$ and cold dark matter ($Λ$CDM) model. A statistically significant detection of any deviations would signify th…

A systematic bias in template-based radial velocity extraction algorithms Open

A.M. Silva, N. C. Santos, J. P. Faria, J. H. C. Martins, E. Cristo , et al. · 2025

Context . The radial velocity (RV) method plays a key role in modern-day astrophysics. One of the most common techniques for extracting precise RVs from state-of-the-art spectrographs is template-matching (TM) algorithms. They have been sh…

Updated constraints on Regge-Teitelboim gravity Open

C. J. A. P. Martins · 2025

In the Regge-Teitelboim model, gravity is described by embedding the space-time manifold in a (usually flat) fixed higher-dimensional background, where the embedding coordinates, rather than the metric tensor, are the dynamical degrees of …

Scaling solutions for current-carrying cosmic string networks. II. Biased solutions Open

Francisco Pimenta, C. J. A. P. Martins · 2025

The charge-velocity-dependent one-scale model is an extension of the canonical velocity-dependent one-scale model which explicitly incorporates additional degrees of freedom on the string worldsheet, such as arbitrary currents and charges,…

The ESPRESSO transmission spectrum of HD189733 b Open

Dany Mounzer, W. Dethier, C. Lovis, V. Bourrier, Angelica Psaridi , et al. · 2025

Context . While transmission spectroscopy has allowed us to detect many atomic and molecular species in exoplanet atmospheres, the improvement in resolution and signal-to-noise ratio (S/N) enabled us to become sensitive to planet-occulted …

Two neighbours of the ultra-short-period Earth-sized planet K2-157 b in the warm Neptunian savanna Open

A. Castro-González, F. Bouchy, A. C. M. Correia, A. Sozzetti, J. Lillo-Box , et al. · 2025

Context . The formation and evolution of ultra-short-period (USP) rocky planets is poorly understood. However, it is widely thought that these planets could not have formed at their present-day close-in orbits, but instead migrated inwards…

The ESPRESSO Redshift Drift Experiment Open

A. Trost, C. M. J. Marques, S. Cristiani, G. Cupani, S. Di Stefano , et al. · 2025

Context. The measurement of the tiny temporal evolution in the redshift of distant objects, the redshift drift, is a powerful probe of universal expansion and cosmology. Aims. We performed the first steps towards the measurement of such an…

Validation of the ESPRESSO wavelength calibration using iodine absorption cell spectra Open

Tobias M. Schmidt, A. Reiners, M. T. Murphy, G. Lo Curto, C. J. A. P. Martins , et al. · 2025

High-quality wavelength calibration is crucial for science cases like radial-velocity studies of exoplanets, the search for a possible variation of fundamental constants, and the redshift drift experiment. However, for state-of-the-art spe…

Probing fundamental physics using compact astrophysical objects Open

E.-A. Kolonia, C. J. A. P. Martins, Konstantinos N. Gourgouliatos · 2025

It is well known that alternative theories to the Standard Model allow—and sometimes require—fundamental constants, such as the fine-structure constant, α, to vary in spacetime. We demonstrate that one way to investigate these variations i…

TOI-512: Super-Earth transiting a K-type star discovered by TESS and ESPRESSO Open

J. Rodrigues, S. C. C. Barros, N.C. Santos, Jeanne Davoult, Mohamed Attia , et al. · 2025

Context. One of the goals of the ESPRESSO guaranteed time observations (GTOs) at the ESO 8.2 m telescope is to follow up on candidate planets from transit surveys such as the TESS mission. High-precision radial velocities are required to c…

Temperature-redshift relation in energy-momentum-powered gravity models Open

C. J. A. P. Martins, A. M. M. Vieira · 2025

There has been recent interest in the cosmological consequences of energy-momentum-powered gravity models, in which the matter side of Einstein's equations includes a term proportional to some power, $n$, of the energy-momentum tensor, in …

Impact of spatial curvature on forecast constraints from standard and differential redshift drift measurements Open

C. J. A. P. Martins, M. A. F. Melo e Sousa, Sónia Fernandes, C. M. J. Marques · 2024

Impact of spatial curvature on forecast constraints from standard and differential redshift drift measurements Open

C. J. A. P. Martins, M. A. F. Melo e Sousa, Susana Fernandes, C. M. J. Marques · 2024

The redshift drift of objects following the cosmological expansion is a unique model-independent probe of background cosmology, detectable by astrophysical facilities presently under construction. Previous forecasts for such measurements a…

A sub-Earth-mass planet orbiting Barnard’s star Open

Atanas K. Stefanov, J. I. Gónzalez Hernández, A. Suárez Mascareño, N. Nari, R. Rébolo , et al. · 2024

A sub-Earth-mass planet orbiting Barnard’s star, designated as Barnard b, has recently been announced. At almost the same time, the first photometric data of Barnard’s star by the Transit Exoplanet Survey Satellite (TESS) was released in S…

Revisiting the multi-planetary system of the nearby star HD 20794 Open

N. Nari, X. Dumusque, N.C. Hara, A. Suárez Mascareño, M. Cretignier , et al. · 2024

Context. Close-by Earth analogs and super-Earths are of primary importance because they will be preferential targets for the next generation of direct imaging instruments. Bright and close-by G-to-M type stars are preferential targets in r…

The obliquity and atmosphere of the hot Jupiter WASP-122b (KELT-14b) with ESPRESSO: An aligned orbit and no sign of atomic or molecular absorption Open

M. Stangret, Ε. Πάλλη, E. Esparza-Borges, J. Orell Miquel, N. Casasayas-Barris , et al. · 2024

Thanks to their short orbital periods and hot extended atmospheres, hot Jupiters are ideal candidates for atmosphere studies with high- resolution spectroscopy. New stable spectrographs help improve our understanding of the evolution and c…

A sub-Earth-mass planet orbiting Barnard’s star Open

J. I. Gónzalez Hernández, A. Suárez Mascareño, A. M. Silva, Atanas K. Stefanov, J. P. Faria , et al. · 2024

Context. ESPRESSO guaranteed time observations (GTOs) at the 8.2m VLT telescope were performed to look for Earth-like exoplanets in the habitable zone of nearby stars. Barnard’s star is a primary target within the ESPRESSO GTO as it is the…

A sub-Earth-mass planet orbiting Barnard's star: No evidence of transits in TESS photometry Open

A. K. Stefanov, J. I. Gónzalez Hernández, A. Suárez Mascareño, N. Nari, R. Rébolo , et al. · 2024

A sub-Earth-mass planet orbiting Barnard's star, designated as Barnard b, has been recently announced. At almost the same time, the first photometric data of Barnard's star by the Transit Exoplanet Survey Satellite (TESS) was released in S…

A speed limit on tachyon fields from cosmological and fine-structure data Open

J. D. F. Dias, Nils Schöneberg, L. Vacher, C. J. A. P. Martins, Samy Vinzl · 2024

The rolling tachyon is a non-canonical scalar field model well motivated in string theory which naturally predicts variations of the fine-structure constant. Such variations can in principle lead to interesting observable consequences, but…

Isotopic abundance of carbon in the DLA towards QSO B1331+170 Open

Dinko Milaković, John K. Webb, P. Molaro, Chung-Chi Lee, Prashin Jethwa , et al. · 2024

Chemical evolution models predict a gradual build-up of 13C in the Universe, based on empirical nuclear reaction rates and assumptions on the properties of stellar populations. However, old metal-poor stars within the Galaxy contain more 1…

ESPRESSO reveals blueshifted neutral iron emission lines on the dayside of WASP-76 b Open

Ana Rita Costa Silva, O. D. S. Demangeon, N. C. Santos, D. Ehrenreich, C. Lovis , et al. · 2024

Context. Ultra hot Jupiters (gas giants with T eq > 2000 K) are intriguing exoplanets due to the extreme physics and chemistry present in their atmospheres. Their torrid daysides can be characterised using ground-based high-resolution emis…

Scaling solutions for current-carrying cosmic string networks Open

Francisco Pimenta, C. J. A. P. Martins · 2024

Cosmic string networks are the best motivated relics of cosmological phase transitions, being unavoidable in many physically plausible extensions of the Standard Model. Most studies, including those providing constraints from and forecasts…

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