尋找 Stripe 82 區域天琴座 RR 恆星中的 Blazhko 效應;Search for the Blazhko Effect in RR Lyrae stars in the Stripe 82 region

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/94639

Title:	尋找 Stripe 82 區域天琴座 RR 恆星中的 Blazhko 效應;Search for the Blazhko Effect in RR Lyrae stars in the Stripe 82 region
Authors:	韋德希;Varma, Vaidehi
Contributors:	天文研究所
Keywords:	天琴座RR;Blazhko effect;變星;寬視野望遠鏡;RR Lyrae;Blazhko effect;Variable stars;wide-field telescopes
Date:	2024-07-18
Issue Date:	2024-10-09 15:20:52 (UTC+8)
Publisher:	國立中央大學
Abstract:	天琴座 RR 星 (RRL) 是脈動週期為 0.2 − 1d 的變星。它們表現出各種各樣的脈動模式，本質上是徑向和非徑向的，但最神秘的是光曲線(LC)中振幅和相位的長期準週期調製，這被稱為 Blazhko 效應。本論文重點研究RRab、RRc和RRd類型RRL的脈動特性，特別關注Blazhko效應。研究選定的區域是位於銀河暈的Stripe 82區域。在 Stripe 82 區域，斯隆數位巡天 (SDSS) 收錄了 483 個 RRL。這些恆星的光曲線(LC) 是透過結合兩個資料集- SDSS 和茲威基瞬態設施(ZTF) 建構的，產生了∼23 年的時間序列，使其成為檢測Blazhko 效應以及一些未被發現的脈動的強大工具模式。使用Period 04 軟體和基於Python 的腳本對LC 進行分析。這兩種方法都發現了 10 顆以前從未被記錄過的 RRd 恆星。 483顆RRL的新分類為:377顆為RRab星，96顆為RRc星，10顆為RRd星。在這些恆星中檢測到了從 1.93 d 到 3253 d 的大範圍 Blazhko 週期 (PB)。在RRab恆星中，Blazhko效應的發生率為21%。觀察到額外的非徑向頻率 (fx)，即使在沒有 Blazhko 效應的情況下也可以檢測到它們。與先前聲稱 fx 僅出現在 Blazhko 型 RRab 恆星中的研究相比，這是一個新的結果。在RRc恆星中，觀測到Blazhko效應的發生率為35%，是有記錄以來最高的發生率。研究也記錄了 SDSS 3585856 的最長 PB 為 3100 d。新發現的10顆RRd星中，一顆異常RRd星的週期比為0.736，其餘經典RRd星的週期比為0.744 − 0.746。 Blazhko 效應出現在 3 顆經典 RRd 恆星中，發生率為 30%。因此，Stripe 82 區域的總發生率為 24%。由於時間序列較長，PB > 200 d 的 Blazhko 效應數量較多。;RR Lyrae stars (RRLs) are variable stars with short pulsation period of 0.2 − 1 d. They display a wide variety of pulsation modes, radial and non-radial in nature, but the most mysterious one is the long-term quasi-periodic modulation of amplitude and phase in the lightcurve (LC) which is called the Blazhko effect. This thesis focuses on the pulsation properties of RRLs of RRab, RRc, and RRd type with the special focus on the Blazhko effect. The area selected for the research is the Stripe 82 region located in the galactic halo. In the Stripe 82 region, 483 RRLs are catalogued by Sloan Digital Sky Survey (SDSS). Lightcurves (LCs) of these stars are constructed by combining two data sets- SDSS and Zwicky Transient Facility (ZTF) which produced ∼23 year-long time-series making them powerful tools in detecting the Blazhko effect as well as some undiscovered pulsation modes. The LCs are analyzed using Period 04 software and using Python based script. Both the approaches lead to the discovery of 10 RRd stars that have never been documented before. The new classification of 483 RRLs is: 377 are RRab stars, 96 are RRc stars, and 10 are RRd stars. A wide range of Blazhko period (PB) from 1.93 d to 3253 d is detected in these stars. Among the RRab stars, the incidence rate of the Blazhko effect is 21%. Additional non-radial frequencies (fx) are observed, and they are detected even in the absence the Blazhko effect. This is a new result when compared to the previous studies which claimed fX appeared only in Blazhko type RRab stars. In RRc stars, the incidence rate of 35% is observed, and it is the higher rate recorded. The study also recorded the longest PB of 3100 d for SDSS 3585856. Newly discovered 10 RRd stars have, among them, one anomalous RRd star with the period ratio of 0.736 and the others classical RRd stars with the period ratio of 0.744 − 0.746. Blazhko effect is seen in 3 classical RRd stars giving an incidence rate of 30%. Thus, the Stripe 82 region has a total incidence rate of 24%. Blazhko effect with PB > 200 d were higher in number because of the long time-series.
Appears in Collections:	[Graduate Institute of Astronomy] Electronic Thesis & Dissertation

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