Search for Flare Stars in TAOS Data
Date Issued
2007
Date
2007
Author(s)
Liu, Chu-Hsin
DOI
en-US
Abstract
中美掩星觀測計畫的目標為測量彗星核大小至幾公里的古柏帶天體之數量與大小分佈。在毎個晴朗的夜晚，超過數百顆背景恆星由三台寬視野(3平方度)、短焦比(f/1.9)、小口徑(50公分)且配備有2k×2k CCD 相機的望遠鏡自動監控。在三台望遠鏡同時操作下，誤報率可因此降低。資料取樣頻率為5 Hz，孔徑測光可至星等約為13.7等的背景恆星。
儘管 TAOS 是為偵測掩星事件而設計，其龐大的資料量與短暫的曝光時間提供了可用於搜尋快速變化之變星的資料庫。由於毎隔0.2秒記錄一次背景恆星的光通量，可偵測到短時間變化變星的更多細節。焰星因為其閃焰的變化時間約為10 分鐘並且在此變化中其亮度於數秒至數分鐘內快速增加，因此被選為主要搜尋的對象。
星球閃焰的亮度與其黑子所佔面積相較於太陽閃焰範圍更廣，相信由TAOS持續累積的龐大資料庫中搜尋更多 dMe 型星可增進對星球閃焰統計上的了解。
The goal of TAOS project is measuring the number and size distribution of Kuiper Belt Objects ( KBOs ) down to a few kilometer size of cometary nuclei. Using three wild-field ( 3 square degrees ), fast ( f/1.9 ) and small ( 50 cm ) robotic telescopes, which equipped with a 2048 by 2048 pixels CCD camera, more than hundreds of stars every clear night are monitored automatically. The telescopes are operated in coincidence mode, hence the false alarm is reduced. The data are taken at 5 Hz, and aperture photometry was completed for stars down to ~13.7 mag.
Although TAOS was designed to detect occultation events, the enormous amount of data and the short exposure time provide an archive for searching variable stars with rapid variabilities. Flux of stars was recorded every 0.2 sec so that more details of a short-timescale variable could be detected. Flare stars were thus chosen to be the primary target because of their extremely short timescale (~10 min) and transient brightening in a few seconds to a few minutes during stellar flares.
Flares in stars cover a much larger range of flare/luminosity ratio and spot/surface ratio than solar flares. With the expected large TAOS database, this paper attempts to find more dMe stars in order to improve the statistical significance of various trends found in stellar flares.
Subjects
中美掩星觀測計畫
焰星
星球閃焰
TAOS
flare star
dMe
stellar flare
Type
other
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