Astronomy & Astrophysics最新文献

{"title":"Unified deep learning approach for estimating the metallicities of RR Lyrae stars using light curves from Gaia Data Release 3","authors":"L. Monti, T. Muraveva, A. Garofalo, G. Clementini, M. L. Valentini","doi":"10.1051/0004-6361/202555681","DOIUrl":"https://doi.org/10.1051/0004-6361/202555681","url":null,"abstract":"<i>Context.<i/> RR Lyrae stars (RRLs) are old population pulsating variables that serve as useful metallicity tracers due to the correlation between their metal abundances and the shape of their light curves. With the advent of ESA’s <i>Gaia<i/> mission Data Release 3 (DR3), which provides light curves for approximately 270 000 RRLs, it has become crucial to develop a machine learning technique for estimating metallicities for large samples of RRLs directly from their light curves.<i>Aims.<i/> We extend our previous methodological study on RRab stars by developing and validating a unified deep learning (DL) framework capable of accurately estimating metallicities for both fundamental mode (RRab) and first-overtone (RRc) pulsators using their <i>Gaia<i/> DR3 <i>G<i/>-band light curves. Our goal is to create a single, consistent model to produce a large, homogeneous metallicity catalogue.<i>Methods.<i/> We employed a gated recurrent units (GRUs)-based neural network architecture optimised for time-series extrinsic regression. The framework incorporates a rigorous pre-processing pipeline (including phase-folding, smoothing, and sample weighting) and is trained using <i>Gaia<i/> DR3 <i>G<i/>-band light curves and photometric metallicities of RRLs available in the literature. The model architecture and training implicitly handle the morphological differences between RRab and RRc light curves.<i>Results.<i/> Our unified GRU model achieves high predictive accuracy. It successfully confirms the high precision for RRab stars reported in our previous work (RMSE = 0.0765 dex, <i>R<i/><sup>2<sup/> = 0.9401) and, crucially, demonstrates even stronger performance for the more challenging RRc stars (RMSE = 0.0720 dex, <i>R<i/><sup>2<sup/> = 0.9625). This represents a significant improvement over previous DL benchmarks. We also present a key finding: a clear positive correlation between the number of photometric data points in a light curve and the precision of the final metallicity estimate; this correlation quantifies the value of well-sampled observations.<i>Conclusions.<i/> Crucially, we demonstrate that prediction accuracy scales with the number of photometric epochs, establishing that this framework is poised to deliver unprecedented precision with richer future datasets. Applying this methodology to the enhanced light curves from <i>Gaia<i/> DR4 and the <i>Vera C. Rubin<i/> Observatory will enable us to produce metallicity catalogues of unprecedented scale and fidelity, paving the way for next-generation studies in Galactic archaeology and chemo-dynamics.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"1 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145311305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Contact binary asteroid (153201) 2000 WO107: Rotation, shape model, and density","authors":"Yurij Krugly, Oleksiy Golubov, Ihor Kyrylenko, Veronika Lipatova, Irina Belskaya, Vasilij Shevchenko, Ivan Slyusarev, Raguli Inasaridze, Shuhrat Ehgamberdiev, Oleksandra Ivanova, Marek Husárik, Sergey Karpov, Daniel Hestroffer","doi":"10.1051/0004-6361/202452553","DOIUrl":"https://doi.org/10.1051/0004-6361/202452553","url":null,"abstract":"<i>Context<i/>. The spectral properties and albedo of near-Earth asteroid (153201) 2000 WO<sub>107<sub/> are consistent with a taxonomic type M. This implies that it might have a high metal abundance and higher density.<i>Aims<i/>. We combined different methods to investigate the asteroid rotation, determine its shape, and use it to estimate its density.<i>Methods<i/>. We carried out photometric observations of the asteroid during the 2020 apparition. We then created a program to simulate the light curves, and used it within a Markov chain Monte Carlo (MCMC) algorithm to reconstruct the asteroid shape model from the observational data. The Goldstone radar observations of the asteroid were used as an additional constraint on the asteroid model in the MCMC algorithm. The estimated shape and rotation rate of the contact binary were used to compute its density.<i>Results<i/>. The photometric observations of (153201) 2000 WO<sub>107<sub/> obtained at a wide range of the phase angles from 5 to 68 degrees in the time interval of November 28 – December 8, 2020, show light curves typical for contact binary asteroids, which agrees with the results of the radar data. The light curves have a maximum amplitude of up to 1.24 mag. The best-fit modeled shape of the asteroid is composed of two ellipsoidal lobes with axes of 0.68 × 0.38 × 0.36 km and 0.44 × 0.42 × 0.16 km. Its sidereal rotation period is determined to be 5.017 ± 0.002 h. The most probable solution for the angular velocity vector of the asteroid indicates ecliptic coordinates of <i>λ<i/> = 96° ± 8° and <i>β<i/> = −78° ± 1°, but another less probable solution of around <i>λ<i/> = 286° ± 11°, <i>β<i/> = −76° ± 2° cannot be disregarded. The estimated density of the asteroid <i>ρ<i/> = 4.80<sub>−0.63<sub/><sup>+0.34<sup/> g/cm<sup>3<sup/> is consistent with a possible metallic composition. From the orbital simulation of this potentially hazardous asteroid, we find that its integral probability of colliding with the Earth in the next 10 000 years is 7 · 10<sup>−5<sup/>.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"58 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145311308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Six microlensing planets detected via sub-day signals during the 2023–2024 season","authors":"Cheongho Han, Chung-Uk Lee, Andrzej Udalski, Ian A. Bond, Michael D. Albrow, Sun-Ju Chung, Andrew Gould, Youn Kil Jung, Kyu-Ha Hwang, Yoon-Hyun Ryu, Yossi Shvartzvald, In-Gu Shin, Jennifer C. Yee, Weicheng Zang, Hongjing Yang, Sang-Mok Cha, Doeon Kim, Dong-Jin Kim, Seung-Lee Kim, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Przemek Mróz, Michał K. Szymański, Jan Skowron, Radosław Poleski, Igor Soszyński, Paweł Pietrukowicz, Szymon Kozłowski, Krzysztof A. Rybicki, Patryk Iwanek, Krzysztof Ulaczyk, Marcin Wrona, Mariusz Gromadzki, Mateusz J. Mróz, Michał Jaroszyński, Marcin Kiraga, Fumio Abe, David P. Bennett, Aparna Bhattacharya, Akihiko Fukui, Ryusei Hamada, Stela Ishitani Silva, Yuki Hirao, Naoki Koshimoto, Yutaka Matsubara, Shota Miyazaki, Yasushi Muraki, Tutumi Nagai, Kansuke Nunota, Greg Olmschenk, Clément Ranc, Nicholas J. Rattenbury, Yuki Satoh, Takahiro Sumi, Daisuke Suzuki, Sean K. Terry, Paul J. Tristram, Aikaterini Vandorou, Hibiki Yama","doi":"10.1051/0004-6361/202554557","DOIUrl":"https://doi.org/10.1051/0004-6361/202554557","url":null,"abstract":"<i>Aims.<i/> We present analyses of six microlensing events: KMT-2023-BLG-0548, KMT-2023-BLG-0830, KMT-2023-BLG-0949, KMT-2024-BLG-1281, KMT-2024-BLG-2059, and KMT-2024-BLG-2242. These were identified in KMTNet data from the 2023–2024 seasons, selected for exhibiting anomalies shorter than one day – potential signatures of low-mass planetary companions. Motivated by this, we conducted detailed investigations to characterize the nature of the observed perturbations.<i>Methods.<i/> Detailed modeling of the light curves reveals that the anomalies in all six events are caused by planetary companions to the lenses. The brief durations of the anomalies are attributed to various factors: a low planet-to-host mass ratio (KMT-2024-BLG-2059, KMT-2024-BLG-2242), a wide planet-host separation (KMT-2023-BLG-0548), small and elongated caustics restricting the source’s interaction region (KMT-2023-BLG-0830, KMT-2024-BLG-1281), and a partial caustic crossing (KMT-2023-BLG-0949).<i>Results.<i/> We estimated the physical parameters of the lens systems using Bayesian analysis. For KMT-2023-BLG-0548, the posterior distribution of the lens mass shows two distinct peaks: a low-mass solution indicating a sub-Jovian planet orbiting an M dwarf in the Galactic disk, and a high-mass solution suggesting a super-Jovian planet around a K-type dwarf in the bulge. KMT-2023-BLG-0830 hosts a Neptune-mass planet orbiting an M dwarf in the Galactic bulge. KMT-2023-BLG-0949 involves a super-Jovian planet orbiting a ~0.5 <i>M<i/><sub>⊙<sub/> host located at ~6 kpc. KMT-2024-BLG-2059Lb is a super-Earth with a mass about seven times that of Earth, orbiting an early M dwarf of ~0.5 <i>M<i/><sub>⊙<sub/>. KMT-2024-BLG-1281L hosts a planet slightly more massive than Neptune, orbiting an M dwarf of ~0.3 <i>M<i/><sub>⊙<sub/>. The short timescale and small angular Einstein radius of KMT-2024-BLG-2242 suggest a ~0.07 <i>M<i/><sub>⊙<sub/> primary, likely a brown dwarf, with a planet of Uranus- or Neptune-like mass.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"109 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145311304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revisiting symbiotic binaries with interferometry","authors":"Henri M. J. Boffin, Jaroslav Merc","doi":"10.1051/0004-6361/202556135","DOIUrl":"https://doi.org/10.1051/0004-6361/202556135","url":null,"abstract":"Symbiotic stars, which generally comprise a red giant and an accreting white dwarf, are excellent laboratories to understand mass transfer in long-period binaries. One of the fundamental questions is how mass is transferred from the red giant to the white dwarf. We used interferometric measurements made with the VLTI/PIONIER instrument, combined with Gaia data, to measure the radius of the giant in seven symbiotic systems. We further placed the giants in the Hertzsprung-Russell diagram, allowing us to estimate their mass and to show that they are all very evolved and likely on the asymptotic giant branch. We compared our measured giant radii to their Roche lobe radius, showing that, except for ZZ CMi, all giants are well within their Roche lobe and that mass transfer likely takes place via stellar wind. Our interferometric data provide further evidence that the giant in ZZ CMi (nearly) fills its Roche lobe. Our conclusions are still hampered by the poor characterisation of some of the giants or their binary orbits, and we encourage the community to make an effort to provide these.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"39 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145311306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Destruction of “peas in a pod?”: A candidate multi-planet system around the nearby bright star HD 208487","authors":"Rafael I. Rubenstein, James S. Jenkins, Pablo A. Peña R., Carolina Charalambous, Mikko Tuomi, Douglas R. Alves, José Vines, Matías R. Díaz, Suman Saha, R. Paul Butler, Jeffrey D. Crane, Steve Shectman, Johanna K. Teske, David Osip, Zahra Essack, Benjamin T. Montet, Adina D. Feinstein, Cristobal Petrovich","doi":"10.1051/0004-6361/202449563","DOIUrl":"https://doi.org/10.1051/0004-6361/202449563","url":null,"abstract":"&lt;i&gt;Aims&lt;i/&gt;. We reinvestigated the HD 208487 system to test the reality of the proposed HD 208487c world. We also searched for additional companions using applied Bayesian statistics and 15+ years of new radial velocity (RV) data from the HARPS and the PFS instruments that were taken post-discovery of HD 208487b, as part of our continued study of bright Sun-like stars within 50 pc of the Sun.&lt;i&gt;Methods&lt;i/&gt;. RV data were analyzed with generalized Lomb-Scargle periodograms, followed by Bayesian analysis techniques using the EMPEROR code. We also scrutinized various stellar activity indices to search for any corresponding peaks in the power spectra, correlations with the RV measurements, or significant signals from a Bayesian analysis methodology. Finally, photometric data were also checked to test for any transits or possible activity manifestations that could lead to possible false RV signals or excess noise.&lt;i&gt;Results&lt;i/&gt;. Our analysis points toward a candidate second planet in the system, positioned near the period of a previously proposed and subsequently challenged signal. This signal, HD 208487c, would relate to a cool Saturn world with an orbital period of 923.06&lt;sub&gt;−2.76&lt;sub/&gt;&lt;sup&gt;+2.02&lt;sup/&gt; d and a minimum mass of &lt;i&gt;M&lt;i/&gt;&lt;sub&gt;&lt;i&gt;j&lt;i/&gt;&lt;sub/&gt;&lt;i&gt;sini&lt;i/&gt; = 0.32 ± 0.01 &lt;i&gt;M&lt;i/&gt;&lt;sub&gt;&lt;i&gt;j&lt;i/&gt;&lt;sub/&gt;. Our analysis also led to a newly discovered candidate planet, HD 208487d, which if confirmed would be the result of a cool super-Neptune-sub-Saturn with a period of 1380.13&lt;sub&gt;−8.25&lt;sub/&gt;&lt;sup&gt;+19.20&lt;sup/&gt; d and a minimum mass of &lt;i&gt;M&lt;i/&gt;&lt;sub&gt;&lt;i&gt;j&lt;i/&gt;&lt;sub/&gt;&lt;i&gt;sini&lt;i/&gt; = 0.15 ± 0.01 &lt;i&gt;M&lt;i/&gt;&lt;sub&gt;&lt;i&gt;j&lt;i/&gt;&lt;sub/&gt;. Neither stellar activity indices nor photometric data show signals statistically matching these periods. We find that stellar activity is indeed affecting the RVs, and yet our joint RV+activity indicator modeling argues they are Doppler in nature. We show that the RV models are stable over long timescales, and these signals are independent of wavelength-dependent noise. The relative contributions of the data to the model were also examined.&lt;i&gt;Conclusions&lt;i/&gt;. We uncovered a candidate three-planet system that would consist of an inner gas giant, a central Saturn, and an outer super-Neptune-sub-Saturn. Extensive analysis of both photometric and spectroscopic data as activity proxies strongly supports the planetary system hypothesis; however, more long-term RV data would help add more statistical weight to the reality of candidate planets c and d. Assuming our model best represents reality, a dynamical analysis suggests that gravitational scattering of an initially ordered, equally spaced system in a long resonant chain of six Neptunes can explain the current architecture of HD 208487, a moderately eccentric inner massive planet with an outer nearly resonant (&lt;i&gt;P&lt;sub&gt;d&lt;sub/&gt;&lt;i/&gt;/&lt;i&gt;P&lt;sub&gt;c&lt;sub/&gt;&lt;i/&gt; = 1.495) gas giant and super-Neptune. More RVs may shed light on the reality of a fourth Doppler signal uncovered in the data that sits close to t","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"354 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145295939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NIRPS and TESS reveal a peculiar system around the M dwarf TOI-756: A transiting sub-Neptune and a cold eccentric giant","authors":"Léna Parc, François Bouchy, Neil J. Cook, Nolan Grieves, Étienne Artigau, Alexandrine L’Heureux, René Doyon, Yuri S. Messias, Frédérique Baron, Susana C. C. Barros, Björn Benneke, Xavier Bonfils, Marta Bryan, Bruno L. Canto Martins, Ryan Cloutier, Nicolas B. Cowan, Daniel Brito de Freitas, Jose Renan De Medeiros, Xavier Delfosse, Elisa Delgado-Mena, Xavier Dumusque, David Ehrenreich, Pedro Figueira, Jonay I. González Hernández, David Lafrenière, Izan de Castro Leão, Christophe Lovis, Lison Malo, Claudio Melo, Lucile Mignon, Christoph Mordasini, Francesco Pepe, Rafael Rebolo, Jason Rowe, Nuno C. Santos, Damien Ségransan, Alejandro Suárez Mascareño, Stéphane Udry, Diana Valencia, Gregg Wade, Manuel Abreu, José L. A. Aguiar, Khaled Al Moulla, Guillaume Allain, Romain Allart, Jose Manuel Almenara, Tomy Arial, Hugues Auger, Luc Bazinet, Nicolas Blind, David Bohlender, Isabelle Boisse, Anne Boucher, Vincent Bourrier, Sébastien Bovay, Pedro Branco, Christopher Broeg, Denis Brousseau, Alexandre Cabral, Charles Cadieux, Andres Carmona, Yann Carteret, Zalpha Challita, David Charbonneau, Bruno Chazelas, Catherine A. Clark, João Coelho, Marion Cointepas, Karen A. Collins, Kevin I. Collins, Uriel Conod, Eduardo Cristo, Ana Rita Costa Silva, Antoine Darveau-Bernier, Laurie Dauplaise, Jean-Baptiste Delisle, Roseane de Lima Gomes, João Faria, Dasaev O. Fontinele, Thierry Forveille, Yolanda G. C. Frensch, Jonathan Gagné, Frédéric Genest, Ludovic Genolet, João Gomes da Silva, Félix Gracia Témich, Nicole Gromek, Olivier Hernandez, Melissa J. Hobson, H. Jens Hoeijmakers, Norbert Hubin, Marziye Jafariyazani, Farbod Jahandar, Ray Jayawardhana, Hans-Ulrich Käufl, Dan Kerley, Johann Kolb, Vigneshwaran Krishnamurthy, Benjamin Kung, Pierrot Lamontagne, Pierre Larue, Henry Leath, Olivia Lim, Gaspare Lo Curto, Allan M. Martins, Elisabeth C. Matthews, Jaymie Matthews, Jean-Sébastien Mayer, Stan Metchev, Lina Messamah, Leslie Moranta, Dany Mounzer, Nicola Nari, Louise D. Nielsen, Ares Osborn, Mathieu Ouellet, Jon Otegi, Luca Pasquini, Vera M. Passegger, Stefan Pelletier, Céline Peroux, Caroline Piaulet-Ghorayeb, Mykhaylo Plotnykov, Emanuela Pompei, Anne-Sophie Poulin-Girard, José Luis Rasilla, Vladimir Reshetov, Jonathan Saint-Antoine, Mirsad Sarajlic, Ivo Saviane, Robin Schnell, Alex Segovia, Julia Seidel, Armin Silber, Peter Sinclair, Michael Sordet, Danuta Sosnowska, Avidaan Srivastava, Atanas K. Stefanov, Márcio A. Teixeira, Simon Thibault, Philippe Vallée, Thomas Vandal, Valentina Vaulato, Joost P. Wardenier, Bachar Wehbe, Drew Weisserman, Ivan Wevers, François Wildi, Vincent Yariv, Gérard Zins","doi":"10.1051/0004-6361/202555684","DOIUrl":"https://doi.org/10.1051/0004-6361/202555684","url":null,"abstract":"<i>Context<i/>. The Near InfraRed Planet Searcher (NIRPS) joined HARPS on the 3.6-m ESO telescope at La Silla Observatory in April 2023, dedicating part of its Guaranteed Time Observations (GTO) program to the radial velocity follow-up of TESS planet candidates to confirm and characterize transiting planets around M dwarfs.<i>Aims<i/>. We present the “Sub-Neptunes” subprogram of the NIRPS-GTO, aimed at investigating the composition and formation of sub-Neptunes orbiting M dwarfs. We report the first results of this program with the characterization of the TOI-756 system, which consists of TOI-756 b, a transiting sub-Neptune candidate detected by TESS, as well as TOI-756 c, an additional non-transiting planet discovered by NIRPS and HARPS.<i>Methods<i/>. We analyzed TESS and ground-based photometry, high-resolution imaging, and high-precision radial velocities (RVs) from NIRPS and HARPS to characterize the two newly discovered planets orbiting TOI-756, as well as to derive the fundamental properties of the host star. A dedicated approach was employed for the NIRPS RV extraction to mitigate telluric contamination, particularly when the star’s systemic velocity was shown to overlap with the barycentric Earth radial velocity.<i>Results<i/>. TOI-756 is a M1V-type star with an effective temperature of <i>T<i/><sub>eff<sub/> ~ 3657 K and a super-solar metallicity ([Fe/H]) of 0.20±0.03 dex. TOI-756 b is a 1.24-day period sub-Neptune with a radius of 2.81 ± 0.10 <i>R<i/><sub>⊕<sub/> and a mass of 9.8<sub>−1.6<sub/><sup>+1.8<sup/> <i>M<i/><sub>⊕<sub/>. TOI-756 c is a cold eccentric (e<sub><i>c<i/><sub/> = 0.45 ± 0.01) giant planet orbiting with a period of 149.6 days around its star with a minimum mass of 4.05 ± 0.11 <i>M<i/><sub>Jup<sub/>. Additionally, a linear trend of 146 m s<sup>−1<sup/> yr<sup>−1<sup/> is visible in the radial velocities, hinting at a third component, possibly in the planetary or brown dwarf regime.<i>Conclusions<i/>. We present the discovery and characterization of the transiting sub-Neptune TOI-756 b and the non-transiting eccentric cold giant TOI-756 c. This system is unique in the exoplanet landscape, standing as the first confirmed example of such a planetary architecture around an M dwarf. With a density of 2.42 ± 0.49 g cm<sup>−3<sup/>, the inner planet, TOI-756 b, is a volatile-rich sub-Neptune. Assuming a pure H/He envelope, we inferred an atmospheric mass fraction of 0.023 and a core mass fraction of 0.27, which is well constrained by stellar refractory abundances derived from NIRPS spectra. It falls within the still poorly explored radius cliff and at the lower boundary of the Neptune desert, making it a prime target for a future atmospheric characterization with JWST to improve our understanding of this population.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"1 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145295906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Twenty years of blazar monitoring with the INAF radio telescopes","authors":"N. Marchili, S. Righini, M. Giroletti, C. M. Raiteri, R. P. Giri, M. I. Carnerero, M. Villata, U. Bach, P. Cassaro, E. Liuzzo, C. S. Buemi, P. Leto, C. Trigilio, G. Umana, M. Bonato, B. Patricelli, A. Stamerra","doi":"10.1051/0004-6361/202556630","DOIUrl":"https://doi.org/10.1051/0004-6361/202556630","url":null,"abstract":"<i>Context<i/>. The extreme variability of blazars, in both timescale and amplitude, is generally explained as the effect of a relativistic jet closely aligned with the observer’s line of sight. Via causality arguments, variability characteristics translate into spatial information about the emitting region of blazars. Since radiation at different wavelengths is emitted in different parts of the jet, multi-frequency observations provide us with a virtual view of the structure of the jet on different scales. Radio-γ-ray correlations, moreover, are essential to revealing where and how the high-energy radiation is produced.<i>Aims<i/>. We present the observations collected within the blazar radio monitoring programme that we are running at the Medicina and Noto telescopes. Its aim is to investigate how the variability characteristics and spectral energy distribution of blazars evolve in time.<i>Methods<i/>. Beginning in 2004, observation were performed at 5, 8, 24, and 43 GHz on 47 targets with a monthly cadence; the monitoring programme is still active at frequencies of 8 and 24 GHz.<i>Results<i/>. The database we have built over more than 20 years of activity comprises to date about 21 000 flux density measurements. Some basic analysis tools have been applied to the data to characterise the detected variability and offer a first glance at the wealth of information that such a programme can provide about blazars.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"11 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145295936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Update of the CODE catalogue and some aspects of the dynamical status of Oort Cloud comets","authors":"Piotr A. Dybczyński, Małgorzata Królikowska","doi":"10.1051/0004-6361/202556678","DOIUrl":"https://doi.org/10.1051/0004-6361/202556678","url":null,"abstract":"<i>Context<i/>. The outer Solar System is believed to host a vast reservoir of long-period comets (LPCs), but our understanding of their spatial distribution and dynamical history remains limited due to observational biases and uncertainties in orbital solutions for really observed comets.<i>Aims<i/>. We aim to provide a comprehensive and dynamically homogeneous orbital database of LPCs to support the study of their origin, evolution, dynamical status, and 6D distribution of orbital elements.<i>Methods<i/>. We updated the Catalogue of Cometary Orbits and their Dynamical Evolution (CODE) by computing original and future barycentric orbits and orbital parameters at previous and next perihelion using full Monte Carlo swarms of real comets for the uncertainty estimation and taking into account the planetary, Galactic, and passing stars’ perturbations according to the latest data and algorithms.<i>Results<i/>. This update of the CODE focuses on the dynamical status of near-parabolic comets. Using current stellar data, we formulated new constraints for dynamically new comets. Today, the CODE database includes 983 orbital solutions for 369 comets with full uncertainty estimates and dynamical classifications, covering nearly all comets with original semi-major axes exceeding 10 000 au and discovered before 2022, as well as all LPCs discovered beyond 10 au from the Sun during this period, and over 80% of the known LPCs with perihelion distances beyond 7 au.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"92 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145295938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrodynamical simulations of planet rebound migration in photo-evaporating disks","authors":"Beibei Liu, Clément Baruteau, Zhaohuan Zhu, Ya-Ping Li, Sijme-Jan Paardekooper","doi":"10.1051/0004-6361/202556167","DOIUrl":"https://doi.org/10.1051/0004-6361/202556167","url":null,"abstract":"This study investigates the orbital migration of a planet located near the truncated edge of protoplanetary disks, induced by X-ray photo-evaporation originating from the central star. The combined effects of turbulent viscous accretion and stellar X-ray photo-evaporation give rise to the formation of a cavity in the central few astronomical units in disks. Once the cavity is formed, the outer disk experiences rapid mass loss and the cavity expands from the inside out. We conducted 2D hydrodynamical simulations of planet-disk interaction for various planet masses and disk properties. Our simulations demonstrate that planets up to about Neptune masses experience a strong positive corotation torque along the cavity edge that leads to sustained outward migration – a phenomenon previously termed rebound migration. Rebound migration is more favorable in disks with moderate stellar photo-evaporation rates of ~10<sup>−8<sup/> M<sub>⊙<sub/> yr<sup>−1<sup/>. Saturn-mass planets only experience inward migration, due to significant gas depletion in their co-orbital regions. In contrast, Jupiter-mass planets are found to undergo modest outward migration as they cause the residual disk to become eccentric. This work presents the first 2D hydrodynamical simulations that confirm the existence and viability of rebound outward migration during the inside-out clearing in protoplanetary disks.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"44 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145295937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discovery of a nova super-remnant surrounding the recurrent nova LMCN 1971-08a in the Large Magellanic Cloud","authors":"Michael W. Healy-Kalesh, Manami Sasaki, Sean D. Points, Miroslav D. Filipović, Zachary J. Smeaton, Matthew J. Darnley, Knox S. Long, Sara Saeedi, Federico Zangrandi","doi":"10.1051/0004-6361/202556670","DOIUrl":"https://doi.org/10.1051/0004-6361/202556670","url":null,"abstract":"A nova super-remnant (NSR) is a greatly-extended structure grown by repeated nova eruptions sweeping the surrounding material away from a nova into a dense outer shell and are predicted to form around all novae. To date, four NSRs are known, with three located in the Galaxy and one residing in M31. Here we present the discovery of the first NSR in the Large Magellanic Cloud and only the second extragalactic nova shell identified, hosted by the recurrent nova LMCN 1971-08a. The structure is coincident with the nova, has a circular morphology, and is visible in narrowband H<i>α<i/> and [S II] filters but is very faint in [O III] , as expected. H I data also potentially reveal the existence of a coincident structure. Further, with a diameter of ∼200 pc, this NSR is the largest example yet found, with models indicating an ∼4130 M<sub>⊙<sub/> shell expanding at ∼20 km s<sup>−1<sup/> into the surrounding medium and an age of ∼2.4 Myr. The existence of the NSR also suggests that LMCN 1971-08a may have a much shorter recurrence period than currently presumed.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"5 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145283183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}