arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2002.01198astro-ph.EPastro-ph.SRphysics.plasm-ph
收藏

热木星HD 209458 b各种物质吸收的三维模拟

Three-dimensional modelling of absorption by various species for hot Jupiter HD 209458b

I F Shaikhislamov, M L Khodachenko, H Lammer, A G Berezutsky, I B Miroshnichenko, M S Rumenskikh

摘要:

HD 209458 b观测到的恒星辐射在OI和CII共振线中的吸收还没有令人满意的模型。在我们以前的二维模拟中,我们已经表明HD 209458 b的上层大气被XUV辐射加热后,以氢为主的物质发生了超声波膨胀,超过了洛希瓣,并将较重的物质拖到了洛希瓣外。假设太阳丰度为10000000,在潮汐力的作用下,OI和CII粒子被加速到50 km/s的速度,由于多普勒共振机制,它们应该产生6- 10%的吸收。与观察结果一致。由于2D几何形状没有考虑行星参考系中的科里奥利力,因此仍然存在这样的问题:逃逸行星物质的螺旋运动及其实际达到的速度在多大程度上会影响基于2D建模得出的结论。在本文中,我们申请的第一次在研究HD209458 b的全球三维流体动力学多流体模型,自洽地描述了逃逸行星风的形成和膨胀,受潮汐力和科里奥利力的影响,以及周围的恒星风。模拟结果证实了我们以前的研究结果,即行星流的速度和密度足够高,以产生在HI,OI和CII共振线的吸收接近在途观测值的水平。新的发现是,在镁II和硅III线测量的吸收匹配需要至少10倍的丰度比这些元素的太阳系的值。

英文摘要:

The absorption of stellar radiation observed by the HD209458b in resonant lines of OI and CII has not yet been satisfactorily modeled. In our previous 2D simulations we have shown that the hydrogen-dominated upper atmosphere of HD209458b, heated by XUV radiation, expands supersonically beyond the Roche lobe and drags the heavier species along with it. Assuming solar abundances, OI and CII particles accelerated by tidal forces to velocities up to 50 km/s should produce the absorption due to Doppler resonance mechanism at the level of 6-10%, consistent with the observations. Since the 2D geometry does not take into account the Coriolis force in the planet reference frame, the question remained to which extent the spiraling of the escaping planetary material and its actually achieved velocity may influence the conclusions made on the basis of 2D modeling. In the present paper we apply for the first time in the study of HD209458b a global 3D hydrodynamic multi-fluid model that self-consistently describes the formation and expansion of the escaping planetary wind, affected by the tidal and Coriolis forces, as well as by the surrounding stellar wind. The modeling results confirm our previous findings that the velocity and density of the planetary flow are sufficiently high to produce the absorption in HI, OI, and CII resonant lines at the level close to the in-transit observed values. The novel finding is that the matching of the absorption measured in MgII and SiIII lines requires at least 10 times lower abundances of these elements than the Solar system values.

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。

↑