New observations of the PZ Tel system, its substellar companion and debris disc⋆
New observations of the PZ Tel system, its substellar companion and debris disc⋆
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对 PZ Tel 系统、其星下伴星和碎片盘的新观测⋆
DOI：
10.1111/j.1365-2966.2012.21216.x
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发表时间：
2012
影响因子：
4.8
通讯作者：
T. Schmidt
中科院分区：
文献类型：
--
作者：
M. Mugrauer;T. Röll;C. Ginski;N. Vogt;R. Neuhäuser;T. Schmidt
我们提出了后续的高对比度成像数据的PZ Tel B，一个太阳类似的前主序星星星和成员的亚恒星的同伴约12万年的老β Pic移动群。在2010年10月至2011年6月期间，我们用纳科/ESO-VLT在三个观测时期内观测了PZ Tel，这证明了PZ Tel B在非常高的显著性水平上的陪伴，并表明PZ Tel系统的光度稳定在10%的水平上。PZ Tel B相对于其主要的轨道运动是清楚地检测到所有观测时期之间，我们甚至发现其轨道运动的减速的证据，如预期的开普勒轨道上的一个对象向其apastron移动。
我们还提出了新的光度测量的PZ Tel最近获得的WISE，这清楚地证实，有没有多余的发射光谱能量分布（SED）的星星高达24 μ m，而一个突出的过剩是在70 μm的MIPS/斯皮策检测。
为了量化PZ Tel系统的轨道要素，我们对纳科采取的所有天体测量措施进行了最小二乘蒙特卡罗（LSMC）拟合。执行LSMC拟合的结果是，由于轨道的天体测量覆盖范围很差，人们还不能确定一个单一的“最佳”拟合轨道解。然而，所获得的良好的LSMC解（）给出了所有轨道根数的分布和相关性的概述。根据我们的LSMC拟合，PZ Tel是一个偏心双星（e <$0.6），轨道根数随着偏心率的增加而退化。
当e < 0.95时，可以看到PZ Tel系统几乎是边缘朝上的（92° ψ i <$110 °），升交点经度50° <$Ω <$65 °，近星点辐角170° <$ω <$290 °，半长轴a大于20 Au，a直方图最高峰位于25 Au左右（或大约110年的轨道周期），直到几十个Au，因为轨道解具有一个明显更大的半长轴将不能够容纳一个环双星盘，激发在PZ Tel A的SED中观察到的过量。
We present follow-up high-contrast imaging data of PZ Tel B, the substellar companion of a solar analogue pre-main-sequence star and member of the approximately 12-Myr-old β Pic moving group. Between 2010 October and 2011 June, we observed PZ Tel in three observing epochs with NACO/ESO-VLT, which proves the companionship of PZ Tel B on a very high significance level and shows that the photometry of the PZ Tel system is stable on the 10 per cent level. The orbital motion of PZ Tel B relative to its primary is clearly detected between all observing epochs, and we even find evidence for deceleration of its orbital motion, as expected for an object on a Keplerian orbit moving towards its apastron.
We also present new photometric measurements of PZ Tel just recently obtained by WISE, which clearly confirm that there is no excess emission in the spectral energy distribution (SED) of the star up to 24 μ m, while a prominent excess is detected at 70 μm with MIPS/Spitzer.
To quantify the orbit elements of the PZ Tel system, we applied a least-squares Monte Carlo (LSMC) fit on all astrometric measures taken with NACO. The results of the performed LSMC fit are that one cannot yet determine a single ‘best'-fitting orbital solution, due to the poor astrometric coverage of the orbit. However, the obtained good LSMC solutions () give an overview of the distributions and correlations of all orbit elements. According to our LSMC fit, PZ Tel is an eccentric binary (e ≳ 0.6), and the orbit elements degenerate with growing eccentricity.
For e < 0.95, the PZ Tel system is seen nearly edge-on (92° ≲ i ≲ 110°), has a longitude of the ascending node of 50° ≲ Ω ≲ 65°, an argument of periastron 170° ≲ ω ≲ 290° and exhibits a semimajor axis a larger than about 20 au, with the highest peak in the a-histogram located at about 25 au (or about 110 yr of orbital period), up to a few tens of au, as orbital solutions with a significantly larger semimajor axis would not be able to harbour a circumbinary disc which excites the observed excess in the SED of PZ Tel A.
双子座 NICI 行星搜寻活动：发现年轻碎片盘恒星 PZ Tel 的近恒星伴星
DOI：
10.1088/2041-8205/720/1/l82
发表时间：
2010
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Biller B
通讯作者：
Biller B