标题： uGMRT M-dwarf周围系外行星调查(GS-EXAM)：GJ 1151的射电观测 显示英文标题

标题： uGMRT Survey of EXoplanets Around M-dwarfs (GS-EXAM): Radio observations of GJ 1151

摘要： 与行星极光信号性质相似的相干射电辐射已被报道来自GJ 1151，这是一颗安静的、慢速旋转的中等M型恒星，通过LOFAR两米（120-170 MHz）天空调查（LoTSS）。观测到的{LOFAR}辐射在0.89 mJy时相当明亮，具有64%的圆偏振度，辐射特性与一个地球大小的行星（轨道周期为1-5天）与宿主恒星磁场之间的相互作用一致。然而，尚未在GJ 1151周围发现短周期行星。为了确认围绕GJ 1151的假想行星引起的射电辐射，并研究这种辐射的性质，我们在33小时内，在十个历元对GJ 1151进行了uGMRT观测，频率分别为150、218和400 MHz。在任何频率上都没有检测到辐射。虽然在150 MHz和218 MHz时，未检测到可能是因为观测灵敏度较低，但在400 MHz时，均方根灵敏度足以检测到LOFAR在$\sim$ 20$\sigma$水平观测到的辐射。我们的研究结果表明，射电辐射具有高度的时间变化性，可能受到恒星-行星系统相位和宿主恒星磁场的影响。需要在170 MHz以下进行额外观测，以更频繁的历元（因为辐射的周期性未知）进行观测，特别是在恒星磁场强度较高的时期，以确认该辐射。 显示英文摘要

摘要： Coherent radio emission with properties similar to planetary auroral signals has been reported from GJ 1151, a quiescent, slow-rotating mid-M star, by the LOFAR Two-metre (120-170 MHz) Sky Survey (LoTSS). The observed {LOFAR} emission is fairly bright at 0.89 mJy with 64% circular polarization, and the emission characteristics are consistent with the interaction between an Earth-sized planet with an orbital period of 1-5 days and the magnetic field of the host star. However, no short-period planet has been detected around GJ 1151. To confirm the reported radio emission caused by the putative planet around GJ 1151 and to investigate the nature of this emission, we carried out uGMRT observations of GJ 1151 at 150, 218, and 400 MHz over 33 hours across ten epochs. No emission was detected at any frequency. While at 150 MHz and 218 MHz, non-detection could be due to the low sensitivity of our observations, at 400 MHz, the rms sensitivities achieved were sufficient to detect the emission observed with LOFAR at $\sim$ 20$\sigma$ level. Our findings suggest that the radio emission is highly time-variable, likely influenced by the star-planet system's phase and the host star's magnetic field. Additional observations below 170 MHz, at more frequent epochs (as the periodicity of the emission is unknown), especially during periods of high stellar magnetic field strength, are needed to confirm the emission.