Spectroscopic and photometric periods of six ultracompact accreting binaries
Spectroscopic and photometric periods of six ultracompact accreting binaries
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DOI：
10.1093/mnras/staa1509
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发表时间：
2020-05
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影响因子：
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通讯作者：
M. Green;T. Marsh;P. Carter;D. Steeghs;E. Breedt;V. Dhillon;S. Littlefair;S. Parsons;P. Kerry-P.
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文献类型：
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作者：
M. Green;T. Marsh;P. Carter;D. Steeghs;E. Breedt;V. Dhillon;S. Littlefair;S. Parsons;P. Kerry-P.
每个超紧凑吸积双星系统都由来自致密供体恒星的恒星残骸吸积富氦材料组成。此类双星包括两个相关的子类：AM CVn型双星和氦灾变变星，两者的中心恒星都是白矮星。我们对轨道周期在 40--70 分钟范围内的六个吸积双星进行了光谱和光度研究，包括相位分辨 VLT 光谱和高速 ULTRACAM 光度测定。其中四个是 AM CVn 系统，两个是氦灾难变量。对于其中四个双星，我们能够识别轨道周期（其中三个是光谱周期）。 SDSS J1505+0659 的轨道周期为 67.8 分钟，明显比之前认为的要长，并且比任何其他已知的 AM CVn 双星都长。我们在 SDSS J1505+0659 中发现了 WISE 红外过量，我们相信这是在非直接撞击双星中首次直接检测到 AM CVn 供体星。 SDSS J1505+0659的质量比与白矮星供体一致。 CRTS J1028-0819 的轨道周期为 52.1 分钟，是所有氦灾难变星中周期最短的。 MOA 2010-BLG-087 与一颗主宰其光谱的 K 级恒星排成一线。 ASASSN-14ei 和 ASASSN-14mv 均在超级爆发后显示出大量的回波爆发（分别为 13 和 10 次回波爆发）。 ASASSN-14ei 显示出其超级爆发后的几年中爆发率有所增加，这可能是由于吸积率增加所致。
Ultracompact accreting binary systems each consist of a stellar remnant accreting helium-enriched material from a compact donor star. Such binaries include two related sub-classes, AM CVn-type binaries and helium cataclysmic variables, in both of which the central star is a white dwarf. We present a spectroscopic and photometric study of six accreting binaries with orbital periods in the range of 40--70 min, including phase-resolved VLT spectroscopy and high-speed ULTRACAM photometry. Four of these are AM CVn systems and two are helium cataclysmic variables. For four of these binaries we are able to identify orbital periods (of which three are spectroscopic). SDSS J1505+0659 has an orbital period of 67.8 min, significantly longer than previously believed, and longer than any other known AM CVn binary. We identify a WISE infrared excess in SDSS J1505+0659 that we believe to be the first direct detection of an AM CVn donor star in a non-direct impacting binary. The mass ratio of SDSS J1505+0659 is consistent with a white dwarf donor. CRTS J1028-0819 has an orbital period of 52.1 min, the shortest period of any helium cataclysmic variable. MOA 2010-BLG-087 is co-aligned with a K-class star that dominates its spectrum. ASASSN-14ei and ASASSN-14mv both show a remarkable number of echo outbursts following superoutbursts (13 and 10 echo outbursts respectively). ASASSN-14ei shows an increased outburst rate over the years following its superoutburst, perhaps resulting from an increased accretion rate.