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arXiv 0809.5041astro-ph
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VV Pup处于低状态:次级恒星辐射或恒星活动?

VV Pup in a low state: secondary-star irradiation or stellar activity?

Elena Mason, Steve B. Howell, Travis Barman, Paula Szkody, Dayal Wickramasinghe

摘要:

目标。在极地的发射线显示复杂的配置文件,具有多个组件,通常归因于吸积流,线程区,吸积点,和照射的次级恒星。在低态极化中,吸积流和吸积斑的贡献率大大降低,这为研究次级星辐射或恒星活动的影响提供了机会。我们观察VV Pup在一个特殊的低状态,研究和限制的线形成区域的属性,并寻找色球活动和/或辐射的证据。方法.我们在ESO VLT+ FORS 1获得了相位分辨光谱,目的是分析发射线轮廓和径向速度作为轨道周期的函数。我们还量身定制的辐照次级恒星模型,比较预测和观察到的发射线,并建立线形成区域的性质。结果我们的观察和数据分析,当与模型相结合的辐照的二次星,表明,虽然弱的低电离金属线(FeI和MgI)可能是一致的辐照过程,占主导地位的巴耳末H的发射线,以及NaI和HeI,不能再现的辐照的二次星模型。我们赞成作为主要的形成区域和观测到的H,碘化钠,和他的发射线的原因,虽然一个线程区域非常接近L1点不能被排除。

英文摘要:

Aims. Emission lines in polars show complex profiles with multiple components that are typically ascribed to the accretion stream, threading region, accretion spot, and the irradiated secondary-star. In low-state polars the fractional contribution by the accretion stream, and the accretion spot is greatly reduced offering an opportunity to study the effect of the secondary-star irradiation or stellar activity. We observed VV Pup during an exceptional low-state to study and constrain the properties of the line-forming regions and to search for evidence of chromospheric activity and/or irradiation. Methods. We obtained phase-resolved optical spectra at the ESO VLT+FORS1 with the aim of analyzing the emission line profile and radial velocity as a function of the orbital period. We also tailored irradiated secondary-star models to compare the predicted and the observed emission lines and to establish the nature of the line-forming regions. Results. Our observations and data analysis, when combined with models of the irradiated secondary-star, show that, while the weak low ionization metal lines (FeI and MgI) may be consistent with irradiation processes, the dominant Balmer H emission lines, as well as NaI and HeI, cannot be reproduced by the irradiated secondary-star models. We favor the secondary-star chromospheric activity as the main forming region and cause of the observed H, NaI, and He emission lines, though a threading region very close to the L1 point cannot be excluded.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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