论文标题
Scutum X-1中的大量AGB供体：X射线二进制中第一个MIRA变量的识别
A massive AGB donor in Scutum X-1: Identification of the first Mira variable in an X-ray binary
论文作者
论文摘要
建议将共生的X射线二进制XCT X-1作为红色超级伴侣的首位已知中子星。尽管近50年来闻名，但仍缺乏对捐赠者的详细表征，尤其是由于对来源的红色极高（$ a_v \ gtrsim25 $ mag）。在这里，我们提出了i）使用Gaia和Chandra观察结果改善了对应物的本地化，II）在NASA红外线望远镜设施和III $ J $ Band Band Light Curve curve Palomar gatt palomar gattii palomar的第一个宽带红外频谱（$ \ of 1-5 \，μ$ m; $ $ m; $ $ \ oble \ of 2000 $）上获得了SPEX。红外光谱的特征是i）深水吸收功能（h $ _2 $ o索引$ \约40 $％），ii）强TIO，VO和CO特征，以及III）弱/不存在CN线。我们表明，这些功能与已知的红色超级巨头不一致，但建议M8-9 III型O-Rich Mira供体明星。我们报告发现大幅度（$ΔJ\ 3.5 $ mag）周期性光度变异性的发现表明，脉动期为$ 621 \ pm36 \，{\ rm（systematic）} \ pm8 \，{\ rm（stative）} （$ m_k = -8.6 \ pm0.3 $ mag）在$ 3.6^{+0.8} _ { - 0.7} $ kpc的距离为$ 3.6^{+0.8}。将这些特征与最近的模型进行比较，我们发现捐赠者与$ \ odot $ star的$ \ 3-5 $ _ \ odot $ star在$ \ \ \ \ \ odot $ \ 0.1-0.3 $ gyr时保持一致。总之，我们表明SCT X-1以前被错误地分类为进化的高质量X射线二元。相反，它是一个中间质量系统，其中X射线二进制中的第一个确认的MIRA供体。我们讨论了Mira捐赠者在共生X射线二进制文件中的含义，并强调了广阔的红外时域调查和宽带红外光谱的潜力，以揭示其人口统计信息。
The symbiotic X-ray binary Sct X-1 was suggested as the first known neutron star accreting from a red supergiant companion. Although known for nearly 50 years, detailed characterization of the donor remains lacking, particularly due to the extremely high reddening towards the source ($A_V\gtrsim25$ mag). Here, we present i) improved localization of the counterpart using Gaia and Chandra observations, ii) the first broadband infrared spectrum ($\approx1-5\,μ$m; $R\approx 2000$) obtained with SpeX on the NASA Infrared Telescope Facility and iii) $J$-band light curve from the Palomar Gattini-IR survey. The infrared spectrum is characterized by i) deep water absorption features (H$_2$O index $\approx 40$%), ii) strong TiO, VO and CO features, and iii) weak/absent CN lines. We show that these features are inconsistent with known red supergiants, but suggest a M8-9 III type O-rich Mira donor star. We report the discovery of large amplitude ($ΔJ\approx3.5$ mag) periodic photometric variability suggesting a pulsation period of $621\pm36\,{\rm(systematic)}\pm8\,{\rm(statistical)}$ days, which we use to constrain the donor to be a relatively luminous Mira ($M_K=-8.6\pm0.3$ mag) at a distance of $3.6^{+0.8}_{-0.7}$ kpc. Comparing these characteristics to recent models, we find the donor to be consistent with a $\approx 3-5$ M$_\odot$ star at an age of $\approx 0.1-0.3$ Gyr. Together, we show that Sct X-1 was previously mis-classified as an evolved High Mass X-ray Binary; instead it is an intermediate mass system with the first confirmed Mira donor in an X-ray binary. We discuss the implications of Mira donors in symbiotic X-ray binaries, and highlight the potential of wide-field infrared time domain surveys and broadband infrared spectroscopy to unveil their demographics.
