Results 21 to 30 of about 15,045 (53)
Observations of Titan’s Stratosphere during Northern Summer: Temperatures, CH3CN and CH3D Abundances
The Planetary Science JournalTitan’s atmospheric composition and dynamical state have previously been studied over numerous epochs by both ground- and space-based facilities. However, stratospheric measurements remain sparse during Titan’s northern summer and fall.
Alexander E. Thelen +13 more
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Absolute Calibration. III. Improved Absolute Calibration for the Visible through the Mid-infrared
The Astronomical Journal, 2023 We propose Sirius as an improved zero-point-defining star and calibrate its spectrum to an accuracy of ∼0.6% in both the visible and infrared. This result is based on a newly derived independent calibration in the visible of similar accuracy to the ...
G. H. Rieke +3 more
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Importance of Sample Selection in Exoplanet-atmosphere Population Studies
The Astronomical Journal, 2022 Understanding planet formation requires robust population studies, which are designed to reveal trends in planet properties. In this work we aim to determine if and how different methods for selecting populations of exoplanets for atmospheric ...
Natasha E. Batalha +7 more
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MeerKAT Holography Measurements in the UHF, L, and S Bands
The Astronomical Journal, 2023 Radio holographic measurements using the MeerKAT telescope are presented for each of its supported observing bands, namely UHF (544–1087 MHz), L (856–1711 MHz), and S (1750–3499 MHz).
Mattieu S. de Villiers
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Target Selection and Validation of DESI Emission Line Galaxies
The Astronomical Journal, 2023 The Dark Energy Spectroscopic Instrument (DESI) will precisely constrain cosmic expansion and the growth of structure by collecting ∼40 million extragalactic redshifts across ∼80% of cosmic history and one-third of the sky. The Emission Line galaxy (ELG)
A. Raichoor +51 more
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Statistical Distribution Function of Orbital Spacings in Planetary Systems
The Astronomical JournalThe minimum orbital separation of planets in long-stable planetary systems is often modeled as a step function, parameterized with a single value ${{\rm{\Delta }}}_{\min }$ (measured in mutual Hill radius of the two neighboring planets).
Jeremy Dietrich +2 more
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The Astronomical Journal, 2023 The fate of planets around rapidly evolving stars is not well understood. Previous studies have suggested that, relative to the main-sequence population, planets transiting evolved stars ( P < 100 days) tend to have more eccentric orbits. Here we present
Samuel K. Grunblatt +29 more
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The Celestial Reference Frame at K Band: Imaging. I. The First 28 Epochs
The Astronomical Journal, 2023 We present K -band (24 GHz) images of 731 compact extragalactic radio sources with submilliarcsecond resolution, based on radio interferometric observations made with the Very Long Baseline Array of 10 telescopes during 29 day long sessions spanning from
Aletha de Witt +6 more
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Kongjian kexue xuebao能量中性原子(Energetic Neutral Atom, ENA)是由能量离子与中性背景成分电荷交换产生. 火星的外逸层扩展范围远高于弓激波, 上游太阳风质子与其相互作用并转化为太阳风氢ENA(Hydrogen-ENA, H-ENA), 新生的H-ENA可直接进入低层大气, 成为新的物质与能量输运通道. 本文基于单流体多成分MHD模型与中性外逸层模型, 计算了火星200 km等高面沉降H-ENA通量的空间分布, 统计了多种太阳风条件下沉降H-ENA的粒子与能量沉降率, 分析影响因素.
张 艺腾 +4 more
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Detection of Atmospheric Escape from Four Young Mini-Neptunes
The Astronomical Journal, 2023 We use Keck/NIRSPEC to survey a sample of of young (
Michael Zhang +7 more
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