28 SiO v = 1 and v = 2, J = 1-0 maser variability in evolved stars. Eleven years of short spaced monitoring
28 SiO v = 1 and v = 2, J = 1-0 maser variability in evolved stars. Eleven years of short spaced monitoring
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DOI：
10.1051/0004-6361:20040309
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发表时间：
2004-09
影响因子：
6.5
通讯作者：
J. Pardo;J. Alcolea;V. Bujarrabal;F. Colomer;A. D. Romero;P. Vicente
中科院分区：
文献类型：
--
作者：
J. Pardo;J. Alcolea;V. Bujarrabal;F. Colomer;A. D. Romero;P. Vicente
本文介绍并讨论了最终的数据集的长期和短距离监测的21 SiO脉泽源，主要是演变的恒星，在两个SiO脉泽线在43 GHz的天文台国家天文台13.7米望远镜在Centro Astronomico de Yebes（瓜达拉哈拉，西班牙）。在大多数物体中，在11年的时间里，每次跃迁都记录了80多个光谱。这里提供的新数据，以前未发表，占该项目收集的SiO数据总量的近50%。此外，在SiO监测的整个期间，可从AAVSO获得大多数物体的光学光变曲线，可从与观测到的SiO周期重叠的4个来源获得地面近红外数据，可从10个来源获得覆盖SiO周期相当大一部分的DIRBE近红外数据，这些都使这套数据成为比较光学、近红外和SiO的变化，以阐明物理机制，泵SiO脉泽在演化的恒星。在这项工作中得到的结论的基础来自于适当的SiO，光学和NIR光变曲线在定期变量的数值时间序列分析，以获得不同曲线之间的周期和相位滞后的精确值。这一分析表明，证据表明，在经常变量演化的恒星的三种类型的发射具有相同的周期和SiO的最大值发生在相位与近红外光谱的最大值和相位滞后通常在0.05和0.20之间的光学最大值。我们的结论是，在这些对象的观测证据，在这项工作中提出的支持辐射泵浦的SiO脉泽对碰撞泵浦。
This paper presents and discusses the final data set of a long-term and short-spaced monitoring of 21 SiO maser sources, mostly evolved stars, carried out in two SiO maser lines at 43 GHz with the Observatorio Astronomico Nacional 13.7 m telescope at the Centro Astronomico de Yebes (Guadalajara, Spain). In most objects, more than 80 spectra per transition over a period of 11 years have been recorded. The new data presented here, previously unpublished, represent nearly 50% of the total SiO data collected in the project. In addition, the availability of optical light curves from the AAVSO for most of the objects during the whole period of the SiO monitoring, ground-based near-IR data for four sources overlapping with 3 to 5 observed SiO periods, and DIRBE near-IR data covering a significant portion of an SiO period in 10 sources, make this data set a unique reference for comparing optical, NIR and SiO variability in order to elucidate the physical mechanisms that pump SiO masers in evolved stars. The basis for the conclusions obtained in this work comes from a numerical time series analysis of the suitable SiO, optical and NIR light curves in regular variables to obtain precise values of the periods and phase lags between the different curves. This analysis shows evidence that in regular variable evolved stars the three types of emission have the same period and that the SiO maxima happen in phase with NIR maxima and with a phase lag typically between 0.05 and 0.20 with respect to optical maxima. We conclude that in these objects the observational evidence presented in this work favors the radiative pumping of SiO masers against the collisional pumping.