Earth and Planetary Astrophysics
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Showing new listings for Friday, 18 April 2025
- [1] arXiv:2504.12541 [pdf, html, other]
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Title: Evolving Atmospheric Ion Escape from Kepler-1649 b and c: Power-Law Trends in Atmospheric LossHaitao Li, Xinke Wang, Chuanfei Dong, Lianghai Xie, Xinyi He, Hong-Liang Yan, Jinxiao Qin, Nathan Mayne, Mei Ting Mak, Nikolaos Georgakarakos, Duncan Christie, Yajun Zhu, Zhaojin Rong, Jinlian Ma, Shi Chen, Hai ZhouComments: 19 pages, 6 figures, 3 tables. Submitted to ApJLSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Rocky planets orbiting M-dwarf stars are prime targets for characterizing terrestrial atmospheres, yet their long-term evolution under intense stellar winds and high-energy radiation remains poorly understood. The Kepler-1649 system, which hosts two terrestrial exoplanets orbiting an M5V star, presents a valuable opportunity to explore atmospheric evolution in the extreme environments characteristic of M-dwarf stellar systems. In this Letter we show that both planets could have retained atmospheres over gigayear timescales. Using a multi-species magnetohydrodynamic model, we simulate atmospheric ion escape driven by stellar winds and extreme ultraviolet radiation from 0.7 to 4.8 Gyrs. The results show that total ion escape rates follow a power-law decline ($\propto \tau^{-1.6}$ for Kepler-1649 b, $\propto \tau^{-1.5}$ for Kepler-1649 c$\,$), with O$^{+}$ dominating atmospheric loss (76.8%-98.7%). The escape rates at 4.8 Gyrs are two orders of magnitude lower than those during the early epochs ($1.9\times10^{27}$ s$^{-1}$ at 0.7 Gyr vs. $3.0\times10^{25}$ s$^{-1}$ at 4.8 Gyrs for planet b$\,$), while planet b consistently exhibits 1.1-1.9$\times$ higher O$^{+}$ escape rates than planet c due to its closer orbit (0.051 AU vs. 0.088 AU). Despite substantial early atmospheric erosion, both planets may still retain significant atmospheres, suggesting the potential for long-term habitability. These findings offer predictive insight into atmospheric retention in M-dwarf systems and inform future JWST observations aimed at refining habitability assessments.
- [2] arXiv:2504.12596 [pdf, html, other]
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Title: Higher-Order Mean-Motion Resonances Can Form in Type-I Disk MigrationComments: 27 pages, 15 figuresSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Type-I disk migration can form a chain of planets engaged in first-order mean-motion resonances (MMRs) parked at the disk inner edge. However, while second- or even third-order resonances were deemed unlikely due to their weaker strength, they have been observed in some planetary systems (e.g. TOI-178 bc: 5:3, TOI-1136 ef: 7:5, TRAPPIST-1 bcd: 8:5-5:3). We performed $>6,000$ Type-I simulations of multi-planet systems that mimic the observed {\it Kepler} sample in terms of stellar mass, planet size, multiplicity, and intra-system uniformity over a parameter space encompassing transitional and truncated disks. We found that Type-I migration coupled with a disk inner edge can indeed produce second- and third-order resonances (in a state of libration) in $\sim 10\%$ and 2\% of resonant-chain systems, respectively. Moreover, the fraction of individual resonances in our simulations reproduced that of the observed sample (notably, 5:3 is the most common second-order MMR). The formation of higher-order MMRs favors slower disk migration and a smaller outer planet mass. Higher-order resonances do not have to form with the help of a Laplace-like three-body resonance as was proposed for TRAPPIST-1. Instead, the formation of higher-order resonance is assisted by breaking a pre-existing first-order resonance, which generates small but non-zero initial eccentricities ($e\approx10^{-3}$ to 10$^{-2}$). We predict that 1) librating higher-order resonances have higher equilibrium $e$ ($\sim 0.1$); 2) be more likely found as an isolated pair in an otherwise first-order chain; 3) more likely emerge in the inner pairs of a chain.
- [3] arXiv:2504.12884 [pdf, html, other]
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Title: TOI-3493 b: A planet with a Neptune-like density transiting a bright G0-type starP. Chaturvedi, E. Goffo, D. Gandolfi, C.M. Persson, A.P. Hatzes, G. Nowak, A. Bonfanti, A. Bieryla, W.D.Cochran, K. A. Collins, S.B. Fajardo-Acosta, S.B. Howell, J.M. Jenkins, J. Korth, J. Livingston, E. Palle, S.N. Quinn, R. P. Schwarz, S. Seager, A. Shporer, K.G. Stassun, S. Striegel, V. Van Eylen, C.N. Watkins, J.N. Winn, C. ZieglerComments: 17 pages, 13 figures, to be published in Astronomy and AstrophysicsSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
We report the discovery of TOI-3493 b, a sub-Neptune-sized planet on an 8.15-d orbit transiting the bright (V=9.3) G0 star HD 119355 (aka TIC 203377303) initially identified by NASA's TESS space mission. With the aim of confirming the planetary nature of the transit signal detected by TESS and determining the mass of the planet, we performed an intensive Doppler campaign with the HARPS spectrograph, collecting radial velocity measurements. We found that TOI-3493 b lies in a nearly circular orbit and has a mass of 9.0+/-1.2 M_earth and a radius of 3.22+/-0.08 R_earth, implying a bulk density of 1.47+/-0.23 g/cm^3, consistent with a composition comprising a small solid core surrounded by a thick H/He dominated atmosphere.
- [4] arXiv:2504.12907 [pdf, html, other]
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Title: De-jittering Ariel: an optimized algorithmAndrea Bocchieri, Lorenzo V. Mugnai, Enzo Pascale, Andreas Papageorgiou, Angele Syty, Angelos Tsiaras, Paul Eccleston, Giorgio Savini, Giovanna Tinetti, Renaud Broquet, Patrick Chapman, Gianfranco SechiComments: 26 pages, 8 figures, accepted in Experimental AstronomySubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
The European Space Agency's Ariel mission, scheduled for launch in 2029, aims to conduct the first large-scale survey of atmospheric spectra of transiting exoplanets. Ariel achieves the high photometric stability on transit timescales required to detect the spectroscopic signatures of chemical elements with a payload design optimized for transit photometry that either eliminates known systematics or allows for their removal during data processing without significantly degrading or biasing the detection. Jitter in the spacecraft's line of sight is a source of disturbance when measuring the spectra of exoplanet atmospheres. We describe an improved algorithm for de-jittering Ariel observations simulated in the time domain. We opt for an approach based on the spatial information on the Point Spread Function (PSF) distortion from jitter to detrend the optical signals. The jitter model is based on representative simulations from Airbus Defence and Space, the prime contractor for the Ariel service module. We investigate the precision and biases of the retrieved atmospheric spectra from the jitter-detrended observations. At long wavelengths, the photometric stability of the Ariel spectrometer is already dominated by photon noise. Our algorithm effectively de-jitters both photometric and spectroscopic data, ensuring that the performance remains photon noise-limited across the entire Ariel spectrum, fully compliant with mission requirements. This work contributes to the development of the data reduction pipeline for Ariel, aligning with its scientific goals, and may also benefit other astronomical telescopes and instrumentation.
- [5] arXiv:2504.12946 [pdf, other]
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Title: Prospects for Detecting Signs of Life on Exoplanets in the JWST EraComments: In press, paper accepted in PNAS on: 2025-01-29Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
The search for signs of life in the Universe has entered a new phase with the advent of the James Webb Space Telescope (JWST). Detecting biosignature gases via exoplanet atmosphere transmission spectroscopy is in principle within JWST's reach. We reflect on JWST's early results in the context of the potential search for biological activity on exoplanets. The results confront us with a complex reality. Established inverse methods to interpret observed spectra-already known to be highly averaged representations of intricate 3D atmospheric processes-can lead to disparate interpretations even with JWST's quality of data. Characterizing rocky or sub-Neptune-size exoplanets with JWST is an intricate task, and moves us away from the notion of finding a definitive "silver bullet" biosignature gas. Indeed, JWST results necessitate us to allow "parallel interpretations" that will perhaps not be resolved until the next generation of observatories. Nonetheless, with a handful of habitable-zone planet atmospheres accessible given the anticipated noise floor, JWST may continue to contribute to this journey by designating a planet as biosignature gas candidate. To do this we will need to sufficiently refine our inverse methods and physical models for confidently quantifying specific gas abundances and constraining the atmosphere context. Looking ahead, future telescopes and innovative observational strategies will be essential for the reliable detection of biosignature gases.
- [6] arXiv:2504.12962 [pdf, html, other]
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Title: Astronomical Refutation of the New Chronology by Fomenko and Nosovsky: The 1151-Year Planetary Cycle and Dating of the Almagest via Speed/Error CorrelationComments: 7 pages, 2 figures. Includes links to code repositories and datasetsSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); History and Philosophy of Physics (physics.hist-ph)
This paper introduces two astronomical methods developed through computational simulation to evaluate the historical dating of ancient astronomical sources. The first identifies a 1151-year planetary cycle based on the recurrence of visible configurations of Mercury to Saturn, including the Sun and Moon, from a geocentric perspective. The second, called SESCC (Speed-Error Signals Cross Correlation), statistically estimates the epoch of star catalogs by analyzing the correlation between positional error and proper motion in ecliptic latitude. Both methods are reproducible, data-driven, and yield results that contradict key tenets of the New Chronology proposed by Fomenko and Nosovsky, most notably the claim that the Anno Domini began in 1152 CE. Open-source code and analysis tools are provided for independent verification.
- [7] arXiv:2504.13039 [pdf, other]
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Title: Evidence for sulfur chemistry in the atmosphere of the warm sub-Neptune TOI-270 dComments: Submitted to A&ASubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Context: Recent JWST measurements allow access to the near-infrared spectrum of the sub-Neptune TOI-270 d, for which two different interpretations, a high-metallicity miscible envelope and a lower metallicity hycean world, are currently in conflict. Aims: Here, we reanalyze the published data and reproduce previously retrieved molecular abundances based on an independent data reduction and a different retrieval framework. The aim of this study is to refine the understanding of TOI-270 d and highlight considerations for JWST data analysis. Additionally, we test the impact of data resolution on atmospheric retrieval calculations. Methods: We reduce one JWST NIRSpec G395H and one NIRISS SOSS GR700XD transit dataset using the Eureka! pipeline and a custom MCMC-based light curve fitting algorithm at the instruments' native resolutions. The atmospheric composition is estimated with the updated BeAR retrieval code across a grid of retrieval setups and spectral resolutions. Results: Our transit spectrum is consistent with previous studies, except at the red end of the NIRISS data. Our retrievals support a higher mean molecular weight atmosphere for TOI-270 d. We provide refined abundance constraints and find statistically favored model extensions indicating either sulfur-rich chemistry with species such as CS2, CS, and H2CS, or the possible presence of CH3Cl or CH3F. However, Bayesian inference cannot distinguish between these scenarios due to similar opacities below 4 microns. Conclusions: Our analysis reinforces TOI-270 d as a highly interesting warm sub-Neptune for atmospheric studies, with a complex chemistry in a cloud-free upper atmosphere. However, its exact nature remains uncertain and warrants further detailed photochemical modeling and observations.
- [8] arXiv:2504.13130 [pdf, html, other]
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Title: General Analytic Solutions for Circumplanetary Disks during the Late Stages of Giant Planet FormationComments: 36 pages, 5 figures, accepted to PASPSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Forming giant planets are accompanied by circumplanetary disks, as indicated by considerations of angular momentum conservation, observations of candidate protoplanets, and the satellite systems of planets in our Solar System. This paper derives surface density distributions for circumplanetary disks during the final stage of evolution when most of the mass is accreted. This approach generalizes previous treatments to include the angular momentum bias for the infalling material, more accurate solutions for the incoming trajectories, corrections to the outer boundary condition of the circumplanetary disk, and the adjustment of newly added material as it becomes incorporated into the Keplerian flow of the pre-existing disk. These generalizations lead to smaller centrifugal radii, higher column density for the surrounding envelopes, and higher disk accretion efficiency. In addition, we explore the consequences of different angular distributions for the incoming material at the outer boundary, with the concentration of the incoming flow varying from polar to isotropic to equatorial. These geometric variations modestly affect the disk surface density, but also lead to substantial modification to the location in the disk where the mass accretion rate changes sign. This paper finds analytic solutions for the orbits, source functions, surface density distributions, and the corresponding disk temperature profiles over the expanded parameter space outlined above.
- [9] arXiv:2504.13160 [pdf, html, other]
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Title: Discovery and Dynamics of the Nontransiting Planet Kepler-139fComments: 12 pages, 6 figures, 1 table. Accepted for publication in ApJLSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Among the ways that an outer giant planet can alter the architecture of an inner planetary system is by tilting the orbits of the inner planets and reducing their mutual transit probabilities. Here, we report on an example of this phenomenon: we show that the Kepler-139 system contains a nontransiting planet just exterior to three transiting planets, and interior to a giant planet. This newly discovered planet, Kepler-139f, has an orbital period of $355 \pm 2$ days and a mass of $36 \pm 10 M_\oplus$ based on transit-timing and radial-velocity data. Through dynamical simulations, we show that gravitational perturbations on planet f's orbit from the outer giant planet reduce the probability for a randomly located observer to see transits of all four inner planets. Thus, Kepler-139 illustrates the role that outer giant planets can play in the apparent truncation of compact systems of multiple transiting planets.
New submissions (showing 9 of 9 entries)
- [10] arXiv:2504.12306 (cross-list from physics.geo-ph) [pdf, html, other]
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Title: Compared analysis of DInSAR data from ascending and descending orbits of Sentinel-1: the Cazzaso case studyGiuseppe Buono, Raffaele Nutricato, Paolo Facchi, Luciano Guerriero, Francesco Vincenzo Pepe, Cosmo Lupo, Saverio PascazioComments: 17 pages, 15 figuresSubjects: Geophysics (physics.geo-ph); Earth and Planetary Astrophysics (astro-ph.EP); Data Analysis, Statistics and Probability (physics.data-an)
Differential SAR interferometry (DInSAR), by providing displacement time series over coherent objects on the Earth's surface (persistent scatterers), allows to analyze wide areas, identify ground displacements, and study their evolution at large times. In this work we implement an innovative approach that relies exclusively on line-of-sight displacement time series, applicable to cases of correlated persistent-scatterer displacements. We identify the locus of the final positions of the persistent scatterers and automatically calculate the lower bound of the magnitude of the potential three-dimensional displacements. We present the results obtained by using Sentinel-1 data for investigating the ground stability of the hilly village Cazzaso located in the Italian Alps (Friuli Venezia Giulia region) in an area affected by an active landslide. SAR datasets acquired by Sentinel-1 from both ascending and descending orbits were processed using the SPINUA algorithm. Displacement time series were analysed in order to solve phase unwrapping issues and displacement field calculation.
- [11] arXiv:2504.12645 (cross-list from astro-ph.SR) [pdf, html, other]
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Title: High-Time-Cadence Spectroscopy and Photometry of Stellar Flares on M-dwarf YZ Canis Minoris with Seimei Telescope and TESS. II. Statistical Properties of Blue/Red Asymmetries in the H$α$ LineComments: 18 pages, 5 figures, 9 tables. Accepted for publication in The Astrophysical JournalSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
M-dwarfs frequently produce flares, and their associated coronal mass ejections (CMEs) may threaten the habitability of close-in exoplanets. M-dwarf flares sometimes show prominence eruption signatures, observed as blue/red asymmetries in the H$\alpha$ line. In Paper I, we reported four candidates of prominence eruptions, which shows large diversity in their durations and velocities. In this study, we statistically investigate how blue/red asymmetries are related with their flare and starspot properties, using the dataset from 27 H$\alpha$ flares in Paper I and previously reported 8 H$\alpha$ flares on an M-dwarf YZ Canis Minoris. We found that these asymmetry events tend to show larger H$\alpha$ flare energies compared to non-asymmetry events. In particular, 5 out of 6 blue asymmetry events are not associated with white-light flares, whereas all 7 red asymmetry events are associated with white-light flares. Furthermore, their starspot distributions estimated from the TESS light curve show that all prominence eruption candidates occurred when starspots were located on the stellar disk center as well as on the stellar limb. These results suggest that flares with lower heating rates may have a higher association rate with prominence eruptions and/or the possibility that prominence eruptions are more detectable on the limb than on the disk center on M-dwarfs. These results provide significant insights into CMEs that can affect the habitable world around M-dwarfs.