Ultra-faint dwarf 為早期宇宙的遺跡，由於其整體光度極低，導致確認其真實距離與物理本質十分不易，RR Lyrae 作為經典的標準燭光，是提供獨立距離估計的關鍵物理探針，本研究利用 DECam 的多波段（g， r， i， z）時間序列成像數據，對 UFD 候選星系 Pictor I 進行了變星搜尋，與過 往類似的 UFD 變星搜尋研究相比，本研究所使用的資料集提供了更密 集的時間採樣，在 i 波段中最多包含高達 51 個曆元。 在候選天體的篩選流程中，本研究將 CMD 條件與 χ2 × MAD 變異 指標相結合，最終篩選出兩顆具變異性的天體，其中一顆分類為 contact binary ，另一顆則為未分類變星，根據推斷出的距離與自行運動數據，這兩顆天體均不支持其為 Pictor I 的成員星，應歸類為銀河系的前景場星。由此觀測結果，本研究推論 Pictor I 缺乏 RR Lyrae，Pictor I 的絕對 V 波段星等更接近 M_V ≈ −2.05 mag。;Ultra-faint dwarf (UFD) galaxies are relics of the early Universe， and their low luminosities make it difficult to confirm their distances and nature. RR Lyrae stars， as standard candles， provide a powerful means of obtaining independent distance estimates. In this work， we conducted a variability search for the UFD candidate Pictor I using archival multiband (g， r， i， z) time-series imaging taken data from the DECam. Compared with similar studies of UFD candidates， this dataset offers denser temporal coverage， with up to 51 epochs in the i-band. Candidate selection was performed by combining color–magnitude diagram (CMD) and filtering with a variability index. Two variable sources were identified: one classified as a contact binary and the other as an unclassified variable. Based on their inferred distance moduli and Gaia proper motions， neither object is consistent with membership in Pictor I， and both are likely foreground stars.We conclude PictorI is lack of RR Lyrae which help in constraing its absolute V-band magnitude as M_V =−2.05mag.
