Imaged Exoplanets(成像的系外行星)到底是什麼？
Imaged Exoplanets 成像的系外行星 - Many exoplanet-focused instruments use a lenslet IFS to make datacubes with spatial and spectral information used to extract spectral information of imaged exoplanets. [1]許多系外行星聚焦儀器使用小透鏡 IFS 製作具有空間和光譜信息的數據立方體，用於提取成像系外行星的光譜信息。 [1]
Directly Imaged Exoplanets 直接成像的系外行星
Measuring the orbits of directly imaged exoplanets requires precise astrometry at the milliarcsec level over long periods of time due to their wide separation to the stars (≳10 au) and long orbital period (≳20 yr). [1] Measurements of the transmission spectra, dayside emission, and phase curves of transiting exoplanets, as well as the emission spectrum and light curves of directly imaged exoplanets and brown dwarfs have shown that aerosols are distributed inhomogeneously in exoplanet atmospheres, with aerosol distributions varying significantly with planet equilibrium temperature and gravity. [2] These are the most challenging directly imaged exoplanets that have been observed at high spectral resolution to date when considering both their angular separations and flux ratios. [3] ExoSpec Project is a NASA Headquarters directed work package that links four different tasks at Goddard space flight center to enable future missions to more efficiently characterize directly imaged exoplanets. [4] We measured the near-infrared linear polarization of 20 known directly imaged exoplanets and brown dwarf companions with the high-contrast imager SPHERE-IRDIS at the VLT. [5] The aim of this project is to investigate biases (deviation of the median and mode of the posterior from the true values of orbital parameters, and the width and coverage of their credible intervals) in the estimation of orbital parameters of directly imaged exoplanets, particularly their eccentricities, and to define general guidelines to perform better estimations of uncertainty. [6] Likewise, it suggests that stable and large scale cloud covers could be ubiquitous in strongly irradiated exoplanets but might be more patchy in low-irradiated or isolated objects like brown dwarfs and directly imaged exoplanets. [7] We suggest that directly imaged exoplanets at large orbital radii, where the disk mass criterion is more likely to be satisfied, could have significant obliquities due to the tilt instability of their circumplanetary disks. [8] The main reason behind the small number of directly imaged exoplanets is that such observations are extremely challenging. [9] Atmospheric characterization of directly imaged exoplanets is currently limited to Giant planets and Mini-Neptunes. [10] The Keck Planet Imager and Characterizer (KPIC) is a novel instrument that combines high-contrast imaging with high-resolution spectroscopy to enable high-dispersion coronagraphy (HDC) techniques that allow us to characterize directly imaged exoplanets at a spectral resolution of R~35,000. [11] In the near term, it will be used to spectrally characterize known directly imaged exoplanets and low-mass brown dwarf companions visible in the northern hemisphere with a spectral resolution high enough to enable spin and planetary radial velocity measurements as well as Doppler imaging of atmospheric weather phenomena. [12] Current and future high-contrast imaging instruments require extreme adaptive optics systems to reach contrasts necessary to directly imaged exoplanets. [13] Reflected starlight measurements will open a new path in the characterization of directly imaged exoplanets. [14] The orbital eccentricities of directly imaged exoplanets and brown dwarf companions provide clues about their formation and dynamical histories. [15] Although HR 8799 e was already known, the interferometry technique could be used to refine the orbits and spectra of directly imaged exoplanets. [16] KPIC will enable High Dispersion Coronagraphy (HDC) of directly imaged exoplanets for the first time, providing potentially improved detection significance and spectral characterization capabilities compared to direct imaging. [17] In this work, we show how it can be used to derive radial velocity (RV) measurements of directly imaged exoplanets. [18]測量直接成像的系外行星的軌道需要在很長一段時間內進行精確的天體測量，因為它們與恆星的距離很遠（≳10 au）和較長的軌道周期（≳20 yr）。 [1] 對凌日系外行星的透射光譜、白天發射和相位曲線的測量，以及直接成像的系外行星和褐矮星的發射光譜和光變曲線的測量表明，氣溶膠在系外行星大氣中分佈不均勻，氣溶膠分佈隨行星的變化而顯著平衡溫度和重力。 [2] 這些是迄今為止在高光譜分辨率下觀察到的最具挑戰性的直接成像系外行星，同時考慮到它們的角間距和通量比。 [3] ExoSpec 項目是 NASA 總部指導的工作包，將戈達德太空飛行中心的四個不同任務聯繫起來，以使未來的任務能夠更有效地表徵直接成像的系外行星。 [4] 我們用 VLT 的高對比度成像儀 SPHERE-IRDIS 測量了 20 顆已知的直接成像系外行星和褐矮星伴星的近紅外線性偏振。 [5] 該項目的目的是研究直接成像系外行星軌道參數估計中的偏差（中值和後驗模式與軌道參數真實值的偏差，以及可信區間的寬度和覆蓋範圍），尤其是它們的軌道參數。偏心率，並定義一般準則以更好地估計不確定性。 [6] 同樣，它表明穩定和大規模的雲層覆蓋在受到強烈輻照的系外行星中可能無處不在，但在低輻照或孤立的物體（如褐矮星和直接成像的系外行星）中可能更加零散。 [7] 我們建議，在大軌道半徑處直接成像的系外行星更可能滿足圓盤質量標準，由於其環繞行星盤的傾斜不穩定性，它們可能具有顯著的傾角。 [8] 少量直接成像的系外行星背後的主要原因是此類觀測極具挑戰性。 [9] 直接成像系外行星的大氣特徵目前僅限於巨行星和迷你海王星。 [10] 凱克行星成像儀和表徵器 (KPIC) 是一種新型儀器，它將高對比度成像與高分辨率光譜相結合，以實現高色散日冕成像 (HDC) 技術，使我們能夠以 R~35,000 的光譜分辨率表徵直接成像的系外行星. [11] 在短期內，它將用於對已知的直接成像系外行星和在北半球可見的低質量褐矮星伴星進行光譜表徵，其光譜分辨率足以實現自旋和行星徑向速度測量以及大氣天氣的多普勒成像現象。 [12] 當前和未來的高對比度成像儀器需要極端的自適應光學系統來達到直接成像系外行星所需的對比度。 [13] 反射星光測量將為直接成像的系外行星的表徵開闢一條新途徑。 [14] 直接成像的系外行星和褐矮星伴星的軌道偏心率為它們的形成和動力學歷史提供了線索。 [15] 儘管 HR 8799 e 已經為人所知，但乾涉測量技術可用於細化直接成像的系外行星的軌道和光譜。 [16] 大韓油化將首次實現直接成像系外行星的高色散日冕成像（HDC），與直接成像相比，提供潛在改進的探測意義和光譜表徵能力。 [17] 在這項工作中，我們展示瞭如何使用它來導出直接成像的系外行星的徑向速度 (RV) 測量值。 [18]