未检测到HD 149427的X射线发射的影响
Implications of the non-detection of X-ray emission from HD 149427
摘要：
HD 149427是一个非常神秘的天体。它被归类为行星状星云或D '型共生星。它的距离也很不确定。此外，HD 149427是一个潜在的喷流源。我们报告的X射线发射的HD 149427的非检测和探讨其性质的影响。我们用XMM-牛顿观测了该物体，有效曝光时间为33.5 ks。在软带（<2 keV）中，X射线发射通量的上限为10^-15 erg/s/cm ^2，而在硬带（>2 keV）中，其上限约为10^-14 erg/s/cm ^2。我们讨论了我们的结果的影响，根据可能的性质HD 149427 -是一个行星状星云或共生星，近或非常遥远。推导出的白矮星的质量吸积率上限对于共生星来说是不典型的，可能有利于HD 149427是一个年轻的PN。HD 149427可能是一颗处于冬眠状态的共生星--如果它真的是一颗共生星的话。我们估计了喷流可能的质量损失率和动力学光度，发现与我们的软X射线发射上限没有矛盾。因此，射流可能仍然存在，但它太微弱，无法通过软X射线发射检测到。
英文摘要：
HD 149427 is a very enigmatic object. It has been classified either as a planetary nebula or as a D'-type symbiotic star. Its distance is also highly uncertain. Furthermore, HD 149427 is a potential jet source. We report the non-detection of X-ray emission from HD 149427 and explore the implications to its nature. We observed the object with XMM-Newton with an effective exposure time of 33.5 ks. The upper limit for the flux of the X-ray emission in the soft band (<2 keV) is 10^-15 erg/s/cm^2, while in the hard band (>2 keV) it is about 10^-14 erg/s/cm^2. We discuss the implication of our results in light of the possible natures of HD 149427 -- being a planetary nebula or a symbiotic star, close or very distant. The derived upper limits on the mass accretion rate of the white dwarf are untypical for symbiotic stars and may favor the picture of HD 149427 being a young PN. HD 149427 might be a symbiotic star in hibernation -- if a symbiotic star at all. We estimate the possible mass-loss rate and kinetic luminosity of the jet and find no contradiction with our upper limit of soft X-ray emission. Therefore the jet may be still present but it was too faint to be detected via soft X-ray emission.
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。
