Rotten Egg nebula: the magnetic field of a binary evolved star
Rotten Egg nebula: the magnetic field of a binary evolved star
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臭鸡蛋星云：双星演化恒星的磁场
DOI：
10.1051/0004-6361/201118303
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发表时间：
2012
影响因子：
6.5
通讯作者：
Desmurs
中科院分区：
文献类型：
--
作者：
Leal-Ferreira;Vlemmings;Diamond;Kemball;Desmurs
大多数观测到的行星状星云（PNe）都不是球形的。球对称性的丧失发生在渐近巨分支（AGB）相和PNe相之间的某处。这种形态变化的原因尚不清楚，但磁场是可能的代理人之一。磁场的起源仍有待确定，可能需要AGB星星的大质量伴星存在。因此，进一步探测演化恒星周围的磁场，特别是那些被认为是双星系统一部分的恒星，对于提高我们对恒星演化后期磁性起源和作用的理解至关重要。一个这样的双星是pre-PN OH231.8+4.2，其周围的磁场已被检测到的OH脉泽区域的外星拱envelope.AimsWe的目的是检测和推断的磁场性质的pre-PN OH231.8+4.2的H2O脉泽区域，探测区域接近中央星星。这个源是一个确认的二进制准直流出和信封包含几个脉泽species.MethodsIn这项工作中，我们观察到的61，6 - 52，3 H2O脉泽旋转过渡，以确定其线性和圆偏振。由于塞曼分裂，磁场的性质可以从脉泽偏振分析中导出。OH 231.8 + 4.2的H2O脉泽发射位于源的内部区域（在几十个Au）。脉泽出现在两个不同的区域，它们在天空中以2.3质量/年的速度移动。考虑到源与视线的倾斜角，这相当于21 km s-1的平均分离速度。根据脉泽发射的速度梯度，脉泽似乎被沿着星云喷流的方向拖曳。线偏振存在于三个特征中，并且圆偏振在两个最亮的特征中被检测到。圆极化结果意味着磁场强度为|B||| ~ 45 mG。结论我们确认了OH 231.8 +4.2周围磁场的存在，并报告了其强度在几十个Au的恒星对的第一次测量。假设有一个环形磁场，这意味着恒星表面的磁场强度为B ~ 2.5G。场的形态尚未确定，但在线性偏振矢量方向上发现的高散射可能表明脉泽发生在环向场的切点附近。
ContextMost of the planetary nebulae (PNe) observed are not spherical. The loss of spherical symmetry occurs somewhere between the asymptotic giant branch (AGB) phase and the PNe phase. The cause of this change of morphology is not yet well understood, but magnetic fields are one of the possible agents. The origin of the magnetic field remains to be determined, and potentially requires the presence of a massive companion to the AGB star. Therefore, further detections of the magnetic field around evolved stars, and in particular those thought to be part of a binary system, are crucial to improve our understanding of the origin and role of magnetism during the late stages of stellar evolution. One such binary is the pre-PN OH231.8+4.2, around which a magnetic field has previously been detected in the OH maser region of the outer circumstellar envelope.AimsWe aim to detect and infer the properties of the magnetic field of the pre-PN OH231.8+4.2 in the H2O maser region that probes the region close to the central star. This source is a confirmed binary with collimated outflows and an envelope containing several maser species.MethodsIn this work we observed the 61,6−52,3H2O maser rotational transition to determine its linear and circular polarization. As a result of Zeeman splitting, the properties of the magnetic field can be derived from maser polarization analysis. The H2O maser emissions of OH231.8+4.2 are located within the inner regions of the source (at a few tens of AU).ResultsWe detected 30 H2O maser features around OH231.8+4.2. The masers occur in two distinct regions that are moving apart with a velocity on the sky of 2.3 mas/year. Taking into account the inclination angle of the source with the line of sight, this corresponds to an average separation velocity of 21 km s-1. Based on the velocity gradient of the maser emission, the masers appear to be dragged along the direction of the nebula jet. Linear polarization is present in three of the features, and circular polarization is detected in the two brightest features. The circular polarization results imply a magnetic field strength of |B||| ~ 45 mG.ConclusionsWe confirm the presence of a magnetic field around OH231.8+4.2, and report the first measurements of its strength within a few tens of AU of the stellar pair. Assuming a toroidal magnetic field, this implesB~ 2.5 G on the stellar surface. The morphology of the field is not yet determined, but the high scatter found in the directions of the linear polarization vectors could indicate that the masers occur near the tangent points of a toroidal field.
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DOI：
10.1086/151852
发表时间：
1973
期刊：
The Astrophysical Journal
影响因子：
--
作者：
P. Goldreich;D. Keeley;J. Kwan
通讯作者：
J. Kwan
未探测到行星状星云 NGC 1360 和 LSS 1362 中心恒星的磁场
DOI：
--
发表时间：
2011
期刊：
影响因子：
--
作者：
F. Leone;M. M. Martínez González;R. Corradi;Giovanni Privitera;R. M. Sainz
通讯作者：
R. M. Sainz
行星状星云 NGC 1360：快风后磁准直和演化的测试案例
DOI：
--
发表时间：
2008
期刊：
影响因子：
--
作者：
M. T. García;J. López;G. García;M. Richer;Wolfgang Steffen
通讯作者：
Wolfgang Steffen
S Per 周围星周水脉泽的圆偏振
DOI：
--
发表时间：
2001
期刊：
影响因子：
--
作者：
W. Vlemmings;P. Diamond;Van Langevelde
通讯作者：
Van Langevelde
行星状星云的巨大挑战
DOI：
--
发表时间：
2007
期刊：
影响因子：
--
作者：
A. Frank;O. Marco;E. Blackman;B. Balick
通讯作者：
B. Balick