XTE J1829−098 is a transient X-ray pulsar with a period of ∼7.8 s. It is a candidate Be star system, although the evidence for this is not yet definitive. We investigated the twenty-year-long X-ray light curve using the Rossi X-ray Timing Explorer Proportional Counter Array (PCA), Neil Gehrels Swift Observatory Burst Alert Telescope, and the Monitor of All-sky X-ray Image. We find that all three light curves are clearly modulated on the ∼244 days orbital period previously reported from PCA monitoring observations, with outbursts confined to a narrow phase range. The light curves also show that XTE J1829−098 was in an inactive state between approximately 2008 December and 2018 April, and no strong outbursts occurred. Such behavior is typical of Be X-ray binary systems, with the absence of outbursts likely related to the dissipation of the Be star's decretion disk. The mean outburst shapes can be approximated with a triangular profile and, from a joint fit of this to all three light curves, we refine the orbital period to 243.95 ± 0.04 days. The mean outburst profile does not show any asymmetry and has a total phase duration of 0.140 ± 0.007. However, the PCA light curve shows that there is considerable cycle-to-cycle variability of the individual outbursts. We compare the properties of XTE J1829−098 with other sources that show short phase-duration outbursts, in particular GS 1843−02 (2S 1845−024), which has a very similar orbital period, but longer pulse period, and whose orbit is known to be highly eccentric.

中文翻译：

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来自 RXTE PCA、Swift BAT 和 MAXI 观测的高质量 X 射线双星 XTE J1829-098 中的尖锐周期性耀斑和长期变化


XTE J1829−098 是一颗周期约为 7.8 s 的瞬态 X 射线脉冲星。这是一个候选的 Be 星系统，尽管这方面的证据尚不明确。我们使用 Rossi X 射线定时探测器比例计数器阵列 （PCA）、Neil Gehrels Swift 天文台爆发警报望远镜和全天空 X 射线图像监视器研究了长达 20 年的 X 射线光曲线。我们发现，所有三条光曲线都在先前从 PCA 监测观测报告的 ∼244 天轨道周期上明显受到调制，爆发仅限于狭窄的相位范围。光曲线还显示，XTE J1829−098 在大约 2008 年 12 月至 2018 年 4 月期间处于非活跃状态，没有发生强烈的爆发。这种行为是 Be X 射线双星系统的典型行为，没有爆发可能与 Be 星的衰减盘耗散有关。平均爆发形状可以用三角形轮廓近似，从三角形轮廓的联合拟合到所有三条光曲线，我们将轨道周期细化为 243.95 ± 0.04 天。平均爆发曲线没有显示出任何不对称性，总相位持续时间为 0.140 ± 0.007。然而，PCA 光曲线显示，单个爆发存在相当大的周期间变化。我们将 XTE J1829-098 的特性与其他显示短相位持续时间爆发的来源进行了比较，特别是 GS 1843-02 （2S 1845-024），它具有非常相似的轨道周期，但脉冲周期更长，并且已知其轨道高度偏心。