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The Astronomical Journal
Scopus
ISSN 0004-6256 · IOP Publishing · 2.474 artikel di indeks
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Artikel Jurnal
Scalable Gaussian Processes for Integrated and Overlapping Measurements via Augmented State-space Models
Astronomical measurements are often integrated over finite exposures, which can obscure latent variability on comparable timescales. Correctly accounting for exposure integration with Gaussian processes (GPs) in such scenarios is essential but computationally challenging: once exposure times vary…
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Artikel Jurnal
Exposure-averaged Gaussian Processes for Combining Overlapping Datasets
Physically motivated Gaussian process (GP) kernels for stellar variability, like the commonly used damped, driven simple harmonic oscillators that model stellar granulation and p -mode oscillations, quantify the instantaneous covariance between any two points. For kernels whose timescales are…
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Artikel Jurnal
A High-resolution Near-Ultraviolet Transmission Spectrum of KELT-9b: Mg II and Fe II Escaping from the Hottest Known Giant Planet
We present high-resolution near-ultraviolet observations from the Hubble Space Telescope’s Space Telescope Imaging Spectrograph (STIS) data for the hottest known gas planet, KELT-9b. Observations were collected with STIS/E230M (2300–3000 Å, R ∼ 30,000), and we decorrelate systematic effects from…
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Artikel Jurnal
Neural Posterior Estimation for Cataloging Astronomical Images from the Legacy Survey of Space and Time
The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will commence full-scale operations in 2026, yielding an unprecedented volume of astronomical images. Constructing an astronomical catalog, a table of imaged stars, galaxies, and their properties, is a fundamental step in most…
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Artikel Jurnal
Oxygen Isotope Constraints on the Importance of Photochemical Processing in Protoplanetary Disks
Observations have revealed evidence of photochemical processing in protoplanetary disks. This processing occurs in the photon-dominated layer, the optically thin regions of the disk high above the disk midplane. It remains unclear, however, how much this photochemical processing impacts the…
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Artikel Jurnal
A Deep Learning–Based Approach for Dielectric Permittivity Inversion of RIMFAX Ground-penetrating Radar Data
The dielectric permittivity is a crucial parameter in planetary ground-penetrating radar (GPR) missions, such as the RIMFAX radar onboard the Mars 2020 Perseverance rover. It characterizes subsurface materials and enables depth interpretation of radargrams. In this study, we develop a deep…
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Artikel Jurnal
Initial Characterization of Stellar Photometry of Roman Images from the OpenUniverse Simulations
NASA’s Nancy Grace Roman Space Telescope (Roman) will provide an opportunity to study dark energy with unprecedented precision and accuracy using several techniques, including measurements of high- z Type Ia Supernovae (SNe Ia; z ≲ 3.0) via the High-Latitude Time Domain Survey (HLTDS). In this…
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Artikel Jurnal
Tracing Galaxy Evolution in the Nearby Universe: The Role of Dark Matter
Using a sample of ∼126,000 late-type galaxies (LTGs) from the Sloan Digital Sky Survey, we analyzed stellar mass as a function of the dynamical mass. Stellar masses are estimated using eight stellar population synthesis (SPS) models with constant initial mass functions (IMFs), while dynamical…
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Artikel Jurnal
First Light for the New 30 m Parabolic Radio Telescope at ArQi: Implications for Space Weather Monitoring
Interplanetary scintillation (IPS) phenomenon behaves as twinkling of a compact radio source due to scattering in the solar wind. Here we report the first identification of IPS signal by a new parabolic dish antenna with its diameter of 30 m, observed on 2024 March 1. The radio source of 3C446 at…
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Artikel Jurnal
Improving Generalization and Uncertainty Quantification of Photometric Redshift Models
Accurate redshift estimates are a vital component in understanding galaxy evolution and precision cosmology. In this paper, we explore approaches to increase the applicability of machine learning models for photometric redshift estimation on a broader range of galaxy types. Typical models are…
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Artikel Jurnal
Quantifying the Contamination of TESS Ecliptic-plane Light Curves by Minor Planets
Though missions devoted to time series photometry focus primarily on targets far beyond the solar system, their observations can be contaminated by foreground minor planets, especially near the ecliptic plane, where solar system objects are most prevalent. Crucially, depending on one’s choice of…
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Artikel Jurnal
Orbits of Twelve Multiple Stars
Inner and outer orbits in 12 hierarchical stellar systems are determined using high-resolution speckle imaging, radial velocities, or both. Masses and fluxes of the components are estimated. The Hipparcos numbers of the main stars are 7111, 12912, 17895, 20375, 42424, 68717, 77439, 79076, 90253…
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Artikel Jurnal
Modeling the Impact of Unresolved Stellar Companions on Detection Sensitivity in Kepler’s Small-planet Occurrence Rates
Unresolved stellar companions can cause both underestimations in the radii of transiting planets and overestimations of their detectability, affecting our ability to reliably measure planet occurrence rates. To quantify the latter, we identified a control sample of 198 Kepler stars with sensitivity…
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Artikel Jurnal
Hipparcos, Gaia, and Radial Velocities Reveal that the Radio-emitting F Star HD 220242 Has an M Dwarf Companion, a Likely Source of the Radio Emission
The detection of circularly polarized, low-frequency radio emission offers the tantalizing possibility of observing interactions between stars and their possible substellar companions, as well as direct emission from exoplanets. Additional follow-up of systems with radio emission is key to…
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Artikel Jurnal
From Earths to Super-Earths: Five New Small Planets Transiting M Dwarf Stars
Earth-sized planets transiting M dwarf stars present one of the best opportunities with current facilities for studying the atmospheric and bulk compositions of terrestrial worlds. Here, we statistically validate five new transiting Earth and super-Earth sized planets orbiting M dwarf stars using a…
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Artikel Jurnal
Validation of a Third Earth-sized Planet in the TOI-2267 Binary System
We report the validation of a third terrestrial exoplanet in the nearby (22 pc) TOI-2267 system. TOI-2267 is a binary system with stellar components TOI-2267A (M5, 3030 K) and TOI-2267B (M6, 2930 K), with an on-sky separation of 0 $\mathop{.}\limits{^{\prime\prime} }$ 384 (8 au projected…
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Artikel Jurnal
The Trajectory of 3I/ATLAS Through the Inner Solar System: Close Encounters and Possible Collisions
3I/ATLAS is the third interstellar object (ISO) identified to date. Unlike other known ISOs, 3I/ATLAS travels on a nearly ecliptic, retrograde orbit ( i ≈ 175°). This trajectory, combined with a small perihelion distance ( q ≈ 1.36 au), directs it through the relatively dense populated regions of…
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Artikel Jurnal
A Search for Late-type Brown Dwarfs in the Euclid Quick Data Release 1
We present the identification and characterization of 15 mid-to-late T dwarf candidates in the Euclid Quick Release 1 (Q1) data set, based on a combined photometric and spectroscopic analysis. Candidates were initially selected via color-based cuts in the Euclid Y _E − J _E and J _E − H _E…
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Artikel Jurnal
Background Intensity Estimation for Cassini–ISS Image Using Deep-learning-based Diffusion Model
Accurate background intensity estimation is crucial for precise astrometric measurements in astronomical imaging, particularly in complex scenarios such as those encountered in Cassini Imaging Science Subsystem (ISS) observations of Saturn’s ring system. Traditional methods such as polynomial…
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Artikel Jurnal
Red Noise–based False Alarm Thresholds for Astrophysical Periodograms via Whittle’s Approximation to the Likelihood
Astronomers who search for periodic signals using Lomb–Scargle periodograms rely on false alarm level (FAL) estimates to identify statistically significant peaks. Although FALs are often calculated from white noise models, many astronomical time series suffer from red noise. Prewhitening is a…
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