系外行星大氣穿透光譜之研究

系外行星大氣光譜分析在這幾年迅速的發展，這是系外行星科學的分支，藉由使用大氣光譜分析，可以顯示出系外行星大氣層的資訊。至今已經有超過4000顆系外行星被發現，所以我們有許多的樣本可以進行分析。因此，我們將介紹一個方法如何表徵系外行星大氣層的性質，藉由使用Metropolis Hastings演算法，我們能夠檢索一些參數，例如大氣層元素豐度、參數化T-P profile的參數。本次的研究是基於Exo-Transmit的程式碼並結合了M-H演算法，此外，我們還修改了Exo-Transmit中EOS的部分，我們將TEA程式碼插入至Exo-Transmit中，用以計算在改變輸入元素豐度，且當化學平衡時，各個化學物質的豐度。根據HST與SST的觀測資料，我們的程式會檢索出適合的參數，並且計算出模擬的穿透光譜、T-P profile以及各個化學物質的含量分布。我們的方法目前只考慮氣相物質的化學平衡情形，而光化學反應、冷凝過程、沉降以及雲霧是我們未來的目標。

關鍵字

系外行星；大氣；穿透光譜

並列摘要

Exoplanet atmospheric spectroscopy is developed fast in recent years. This is a branch of Exoplanetology. Exoplanet atmospheric spectroscopy can reveal informa-tion of exoplanetary atmosphere. More than 4000 exoplanets have been detected so far, we have a lot of samples can be analyzed and characterized. Thus, we present a method which is used to char-acterize exoplanetary atmosphere properties. We used Metropolis-Hastings algorithm (MCMC) to retrieve parameters, such as elemental abundances and some parameters of parametric T-P profile. This work is based on Exo-Transmit code and combined with M-H algorithm. Furthermore, we modify the EOS part in Exo-Transmit. We in-sert TEA code into Exo-Transmit to calculate chemical equilibrium abundances by changing input elemental abundances. According to observational data from HST and SST, our method can retrieve suitable parameters and generate transmission spectrum, T-P profile and chemical abundances mixing ratio. For now, our method only considers chemical equilibrium in gaseous species. Photochemical process, condensation process, rain-out and cloud are our future goal.