“DODO“巡天I：范马宁恒星（vMa 2）的超冷亚恒星和行星质量伴星的极限
The "DODO" survey I: limits on ultra-cool substellar and planetary-mass companions to van Maanen's star (vMa 2)
摘要：
我们报告的限制，在行星质量制度的同伴周围最近的一个白矮星到太阳，范马宁的明星（vMa 2），从深J波段成像与双子座北和斯皮策IRAC中红外测光。我们发现，没有解决共同的自行同伴vMa 2在3”- 45”的分离，在J~23的极限星等。假设系统的总年龄为4.1 +/-1 Gyr，并利用最新的亚恒星天体演化模型，这个极限相当于伴星质量>7 +/-1 Mjup（T~ 300 K）。考虑到非常低质量的伴星在后主序星阶段可能的轨道演化，这些J波段观测有效地测量了3 - 50天文单位的白矮星周围的轨道。在任何赠送的斯皮策IRAC中红外滤光片中均未检测到通量过量。用光学BVRI、2 MASS JHK和IRAC测光方法拟合了DZ白矮星模型大气。最佳解给出T=6030 +/-240 K，log g=8.10 +/-0.04，因此，M= 0.633 +/-0.022Msun。然后，我们对4.5微米带中任何未分辨伴星的质量设置10 +/-2兆焦耳的3西格玛上限。
英文摘要：
We report limits in the planetary-mass regime for companions around the nearest single white dwarf to the Sun, van Maanen's star (vMa 2), from deep J-band imaging with Gemini North and Spitzer IRAC mid-IR photometry. We find no resolved common proper motion companions to vMa 2 at separations from 3" - 45", at a limiting magnitude of J~23. Assuming a total age for the system of 4.1 +/-1 Gyr, and utilising the latest evolutionary models for substellar objects, this limit is equivalent to companion masses >7 +/-1 Mjup (T~300K). Taking into account the likely orbital evolution of very low mass companions in the post-main sequence phase, these J-band observations effectively survey orbits around the white dwarf progenitor from 3 - 50AU. There is no flux excess detected in any of the complimentary Spitzer IRAC mid-IR filters. We fit a DZ white dwarf model atmosphere to the optical BVRI, 2MASS JHK and IRAC photometry. The best solution gives T=6030 +/- 240K, log g=8.10 +/-0.04 and, hence, M= 0.633 +/-0.022Msun. We then place a 3sigma upper limit of 10 +/-2 Mjup on the mass of any unresolved companion in the 4.5 micron band.
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。
