郭新臺灣大學：天文物理研究所彭子誠Peng, Tzu-ChengTzu-ChengPeng2007-11-262018-06-282007-11-262018-06-282006http://ntur.lib.ntu.edu.tw//handle/246246/52033無論是在宇宙間或太陽系內，都顯示著磷的豐富含量。然而在星際介質中，目前只有氮化磷(PN)與碳化磷(CP)被天文學家觀測到。根據化學理論與模型預測，一氧化磷(PO)為豐度最高的含磷分子，雖然之前的觀測尚未證實這點。因此，尋找星際間的一氧化磷將有助於天文學家，釐清為何大部分的含磷分子都未被觀測到。我們利用美國亞歷桑納天文台十二米望遠鏡及十米次毫米波望遠鏡進行一氧化磷觀測，並挑選了兩個富含許多分子的天體。一為Orion KL，是獵戶座大星雲中的熱分子雲核心，並伴隨著許多大質量恆星的形成。另一個為IRC+10216，是一顆距離我們相當近的演化末期恆星，許多分子都在這顆恆星的周圍形成。觀測結果顯示，一氧化磷出現在Orion KL，而在IRC+10216並沒有任何一氧化磷被觀測到。同時結果也指出一氧化磷可能來自Orion KL的特定區域，這些證據可以讓我們更了解一氧化磷的形成機制與形成環境。Even though phosphorus is abundant in the Universe, only PN and CP are detected in the interstellar medium. PO, which could be the most plentiful phosphorus-bearing molecule, has not been successfully detected yet. We have therefore searched for the PO transitions in the massive star-forming region Orion KL and the carbon-rich star IRC+10216 with the ARO 12 meter telescope and Submillimeter telescope. Our results show detections of PO in Orion KL but non-detections in IRC+10216. The PO line profiles indicate that the PO emission comes from the Compact Ridge of Orion KL. In addition, the HCP detection at IRC+10216 in our observations suggests the formation of CP is associated with HCP.1 Introduction 1 1.1 Phosphorus . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.1 Biochemical Importance of Phosphorus . . . . . . . . 1 1.1.2 Cosmic Phosphorus and Its Abundance . . . . . . . . 1 1.1.3 Depletion of P-bearing Molecules . . . . . . . . . . . . 2 1.1.4 Previous PO Observations . . . . . . . . . . . . . . . . 3 1.2 Target Sources . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2.1 Orion KL . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2.2 IRC+10216 . . . . . . . . . . . . . . . . . . . . . . . . 6 2 Phosphorus Monoxide 11 2.1 Basic Chemical Constants of PO . . . . . . . . . . . . . . . . 11 2.2 Energy Levels and Transitions . . . . . . . . . . . . . . . . . . 13 2.3 The Formation of PO . . . . . . . . . . . . . . . . . . . . . . 13 3 Observations and Telescopes 17 3.1 Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3.2 KP 12 Meter Telescope (KP 12m) . . . . . . . . . . . . . . . 17 3.2.1 Telescope Optics . . . . . . . . . . . . . . . . . . . . . 18 3.2.2 The LO System and IF Section . . . . . . . . . . . . . 18 3.2.3 Spectrometers . . . . . . . . . . . . . . . . . . . . . . . 19 3.3 Submillimeter Telescope (SMT) . . . . . . . . . . . . . . . . . 19 3.3.1 Telescope Optics . . . . . . . . . . . . . . . . . . . . . 20 3.3.2 The LO System and IF Section . . . . . . . . . . . . . 20 3.3.3 Spectrometers . . . . . . . . . . . . . . . . . . . . . . . 21 3.4 Observation Settings and Procedures . . . . . . . . . . . . . . 22 3.4.1 Tracking . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.4.2 Pointing . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.4.3 Focus . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3.4.4 Spectrometer Settings . . . . . . . . . . . . . . . . . . 23 3.4.5 Calibration . . . . . . . . . . . . . . . . . . . . . . . . 23 4 Data Reduction and Line Identifications 26 4.1 Data Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . 26 4.2 Orion KL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 4.2.1 Detections of PO 2 1/2 State . . . . . . . . . . . . . . 27 4.2.2 Detections of PO 2 3/2 State . . . . . . . . . . . . . . 29 4.2.3 Rotational Temperature Diagram of PO . . . . . . . . 29 4.2.4 Other Detected Lines in Orion KL . . . . . . . . . . . 30 4.3 IRC+10216 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 4.3.1 The Upper Limit of PO Column Density . . . . . . . . 47 4.3.2 HCP in IRC+10216 . . . . . . . . . . . . . . . . . . . 48 4.3.3 Other Detected Lines in IRC+10216 . . . . . . . . . . 50 5 Discussions 58 5.1 Orion KL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 5.1.1 The Origin of PO in Orion KL . . . . . . . . . . . . . 58 5.1.2 The Relation Between PN and PO in Orion KL . . . . 59 5.2 IRC+10216 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 5.2.1 The Relation Between HCP and CP in IRC+10216 . . 60 6 Conclusions 62 Appendix A A Column Density Calculation 64 Bibliography 6816597237 bytesapplication/pdfen-US星際介質分子磷ISMMoleculePhosphorusotherhttp://ntur.lib.ntu.edu.tw/bitstream/246246/52033/1/ntu-95-R93244007-1.pdf