arXiv subjects

Santiago Iglesias Álvarez

Publications and source records attributed to Santiago Iglesias Álvarez.

6 recordsLinked to original sources

arXiv2026

On the rotation of M-type asteroids: statistical evidence for higher rotation rates

Rotational dynamics of asteroids carry important information about their internal structure, collisional history and material composition. This work investigates whether M-type asteroids exhibit systematically higher rotation rates than the broader asteroid population. Using Mahlke's probabilistic taxonomy combined with rotation periods and diameters from the Small-Body Database, we analyse the rotational properties of candidate M-type asteroids and compare them with the general asteroid population. Because asteroid rotation strongly depends on size, the comparison is performed using a Monte Carlo resampling approach conditioned on the diameter distribution of the M-type sample. The results indicate that the M-type asteroids rotate, on average, faster than other asteroids of comparable size. While limitations remain due to sample size, heterogeneous data sources, and possible selection effects, the analysis provides statistical evidence that M-type asteroids are associated with higher rotation rates. This finding is consistent with an association between M-type classification and enhanced rotational properties, with potential implications for the internal structure and collisional evolution of small bodies in the Solar System.

astro-ph.EP↗

arXiv2026

Spin Parameters and Shape Models of Near-Earth Asteroids (4660) Nereus, (21088) Chelyabinsk, (66146) 1998 TU3, and (297418) 2000 SP43

We present our shape and rotational characterization of four near-Earth asteroids observed as part of the Visible NEAs Observations Survey. This work includes 61 new light curves obtained between 2020 June and 2024 September for asteroids (21088) Chelyabinsk and (66146) 1998 TU3 and the potentially hazardous asteroids (4660) Nereus and (297418) 2000 SP43. We combine these observations with archival data to derive their shape models, spin parameters, and refined rotation periods using a light-curve inversion method. Our derived rotational periods are consistent with previously published values for all the objects. We present constant-period models for each asteroid, while for (66146) 1998 TU3 we detect a possible Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) acceleration of $\upsilon \simeq 2.05 \times 10^{-8} \text{ rad day}^{-2}$, potentially adding it to the short list of asteroids known to experience the YORP effect.

astro-ph.EP↗

arXiv2024

Light-curve analysis and shape models of NEAs 7335, 7822, 154244 and 159402

In an attempt to further characterise the near-Earth asteroid (NEA) population we present 38 new light-curves acquired between September 2020 and November 2023 for NEAs (7335) 1989 JA, (7822) 1991 CS, (154244) 2002 KL6 and (159402) 1999 AP10, obtained from observations taken at the Teide Observatory (Tenerife, Spain). With these new observations along with archival data, we computed their first shape models and spin solutions by applying the light curve inversion method. The obtained rotation periods are in good agreement with those reported in previous works, with improved uncertainties. Additionally, besides the constant period models for (7335) 1989 JA, (7822) 1991 CS and (159402) 1999 AP10, our results for (154244) 2002 KL6 suggest that it could be affected by a Yarkovsky-O'Keefe-Radzievskii-Paddack acceleration with a value of $\upsilon \simeq -7 \times 10^{-9}$ rad d$^{-2}$. This would be one of the first detections of this effect slowing down an asteroid.

astro-ph.EP↗

arXiv2024

Computing Transiting Exoplanet Parameters with 1D Convolutional Neural Networks

The transit method allows the detection and characterization of planetary systems by analyzing stellar light curves. Convolutional neural networks appear to offer a viable solution for automating these analyses. In this research, two 1D convolutional neural network models, which work with simulated light curves in which transit-like signals were injected, are presented. One model operates on complete light curves and estimates the orbital period, and the other one operates on phase-folded light curves and estimates the semimajor axis of the orbit and the square of the planet-to-star radius ratio. Both models were tested on real data from TESS light curves with confirmed planets to ensure that they are able to work with real data. The results obtained show that 1D CNNs are able to characterize transiting exoplanets from their host star's detrended light curve and, furthermore, reducing both the required time and computational costs compared with the current detection and characterization algorithms.

astro-ph.EP↗

arXiv2023

Improved models for near-Earth asteroids (2100) Ra-Shalom, (3103) Eger, (12711) Tukmit & (161989) Cacus

We present 24 new dense lightcurves of the near-Earth asteroids (3103) Eger, (161989) Cacus, (2100) Ra-Shalom and (12711) Tukmit, obtained with the Instituto Astrofísico Canarias 80 and Telescopio Abierto Remoto 2 telescopes at the Teide Observatory (Tenerife, Spain) during 2021 and 2022, in the framework of projects visible NEAs observations survey and NEO Rapid Observation, Characterization and Key Simulations. The shape models and rotation state parameters ($P$, $λ$, $β$) were computed by applying the lightcurve inversion method to the new data altogether with the archival data. For (3013) Eger and (161989) Cacus, our shape models and rotation state parameters agree with previous works, though they have smaller uncertainties. For (2100) Ra-Shalom, our results also agree with previous studies. Still, we find that a Yarkovsky - O'Keefe - Radzievskii - Paddack acceleration of $\upsilon = (0.223\pm0.237)\times10^{-8}$ rad d$^{-2}$ slightly improves the fit of the lightcurves, suggesting that (2100) Ra-Shalom could be affected by this acceleration. We also present for the first time a shape model for (12711) Tukmit, along with its rotation state parameters ($P=3.484900 \pm 0.000031$ hr, $λ= 27^{\circ}\pm 8^{\circ}$, $β= 9^{\circ} \pm 15^{\circ}$).

astro-ph.EP↗

arXiv2023

One-dimensional Convolutional Neural Networks for Detecting Transiting Exoplanets

The transit method is one of the most relevant exoplanet detection techniques, which consists of detecting periodic eclipses in the light curves of stars. This is not always easy due to the presence of noise in the light curves, which is induced, for example, by the response of a telescope to stellar flux. For this reason, we aimed to develop an artificial neural network model that is able to detect these transits in light curves obtained from different telescopes and surveys. We created artificial light curves with and without transits to try to mimic those expected for the extended mission of the Kepler telescope (K2) in order to train and validate a 1D convolutional neural network model, which was later tested, obtaining an accuracy of 99.02 % and an estimated error (loss function) of 0.03. These results, among others, helped to confirm that the 1D CNN is a good choice for working with non-phased-folded Mandel and Agol light curves with transits. It also reduces the number of light curves that have to be visually inspected to decide if they present transit-like signals and decreases the time needed for analyzing each (with respect to traditional analysis).

astro-ph.EP↗