Abstract

The observations and comprehensive study of intermediate initial mass stars at the late stages of evolution, and after the asymptotic giant branch (AGB) in particular, are of crucial importance to identify the common properties for the stars of given group and to reveal binaries among them. This work aims to investigate photometric and spectral peculiarities of a poorly studied post-AGB candidate and infrared source IRAS 07253–2001. We present the new multicolor \(UBVR_{C}I_{C}YJHK\) photometry obtained with the telescopes of the Caucasian mountain observatory and analyse it together with the data acquired by the All Sky Automated Survey for SuperNovae. We report on the detection of multiperiod brightness variability caused by pulsations. A beating of close periods, the main one of 73 days and additional ones of 68 and 70 days, leads to amplitude variations. We have also detected a long-term sine trend in brightness with a period of nearly 1800 days. We suppose it to be orbital and IRAS 07253–2001 to be binary. Based on new low-resolution spectroscopic data obtained with the 2.5-m telescope of the Caucasian mountain observatory in 2020 and 2023 in the \(\lambda\) 3500–7500 wavelength range we have identified spectral lines and compiled a spectral atlas. We have found the [N II], [Ni II] and [S II] forbidden emission lines in the spectrum and discuss their origin. The H\(\alpha\) line has a variable double-peaked emission component. We have derived preliminary estimates of the star’s parameters and detected a variation of radial velocity with a peak-to-peak amplitude of about 30 km s\({}^{-1}\).

中文翻译：

---

后 AGB 之星 IRAS 07253–2001：脉动、长期亮度变化和光谱特性

摘要

对演化后期，特别是渐近巨星分支（AGB）之后的中等初始质量恒星的观测和综合研究，对于识别特定群体恒星的共同属性并揭示其中的双星至关重要。这项工作旨在研究研究较少的后 AGB 候选红外源 IRAS 07253–2001 的光度和光谱特性。我们展示了用高加索山天文台的望远镜获得的新的多色\(UBVR_{C}I_{C}YJHK\)光度测量，并将其与超新星全天自动巡天获取的数据一起进行分析。我们报告了由脉动引起的多周期亮度变化的检测。临近周期的跳动（主要周期为 73 天，附加周期为 68 天和 70 天）会导致振幅变化。我们还检测到亮度的长期正弦趋势，周期接近 1800 天。我们假设它是轨道的，而 IRAS 07253-2001 是双星的。根据高加索山天文台2.5米望远镜于2020年和2023年在\(\lambda\) 3500–7500波长范围内获得的新的低分辨率光谱数据，我们识别了谱线并编制了光谱图集。我们在光谱中找到了[N II]、[Ni II]和[S II]禁发射线并讨论了它们的起源。H \(\alpha\)线具有可变的双峰发射分量。我们对恒星的参数进行了初步估计，并检测到径向速度的变化，峰峰值幅度约为 30 km s \({}^{-1}\)。