此研究聚焦在年輕恆星及亞恆星的早期演化，以不同質量範圍探討：（1）大質量恆星誕生後對周遭分子雲，包括引發下一代恆星形成的影響；（2）亞恆星天體的形成；以及（3）低質量恆星和棕矮星配對的雙星系統。Sh2-142是個氫游離區，除了有大質量恆星，周圍也有分子雲，以及游離雲，已經年輕星團，我們利用多波段觀測數據，包括紅外波段影像、一氧化碳分子光譜的空間分布，結果揭示了分子雲的動力和結構明顯受到大質量恆星影響，並進而引發新一代的恆星誕生。在極低質量天體方面，我們研究了蛇夫座ρ星雲當中的主要恆星形成區，亦即L1688星雲當中，利用它們低溫大氣中的水吸收光譜特性，以紅外成像法來指認這些理論上未能點燃核融合的候選棕矮星。針對比較明亮的目標，我們取得紅外光譜，確認它們的低溫大氣特性；我們也利用深度的紅外影像，推測它們的自行運動，以判斷是否與年輕恆星成協。有些目標的光譜展現了吸積，同時光譜能量分布顯示周圍有環星盤，表示這些棕矮星的誕生類似恆星，而非行星。針對低質量天體，我們透過LAMOST 確認為晚M型天體的目標，尋找Gaia 的共行伴星，進一步計算這些低量雙星對的質量比和投影在天球的分離距等雙星統計，依此證明它們經由雲核分裂而誕生。

This research centers around young stellar and substellar objects in their pre-stellar or pre-main sequence phase. Investigating different mass regimes, this work explores three aspects of star formation: (1) the feedback from massive stars to trigger subsequent star formation, (2) the formation mechanism of substellar objects in comparison to stellar
objects, and (3) low-mass and brown dwarf pairs. The influence of massive star was investigated in Sh2-142 cloud complex fostering an H II region. We explored the connection between young stellar population and gas in the complex, the former selected and analysed through archival infrared photometry and the latter through CO molecular line data. Our analysis revealed the observed kinematics and structure of molecular gas were shaped under the influence of massive star. The relative positioning of young stellar objects and ionizing source of the region, suggested that the
stellar feedback may have triggered the formation of new generation of stars. Substellar objects for the young star forming core of Rho Oph i.e., L1688 A, were identified through molecular - absorption feature implementing the Water-filter (W-band) observations. Proper motions of the sample were derived to assess their membership from deep archival infrared images. Near infrared spectroscopy of a few bright candidates confirmed signatures of magnetospheric accretion in two disk bearing sources. We also spectroscopically confirmed an M8-type substellar object exhibiting possible signs of binarity. A high prevalence of disks in our sample based on the assessment of spectral energy distribution suggested a common formation pathway for stellar and substellar objects.
An investigation of low mass and brown dwarf comoving pairs is presented. The sample was selected from LAMOST low resolution spectroscopic data/catalog, and possible comoving companions were searched with Gaia kinematics and parallax data. Investigation of mass ratio and projected separation of the pairs suggested their formation through core fragmentation.

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