论文标题
随着世界的转变：限制行星质量制度中的旋转演变
As the Worlds Turn: Constraining Spin Evolution in the Planetary-Mass Regime
论文作者
论文摘要
为了了解行星旋转如何演变和痕迹行星形成过程，我们使用NIRSPEC/Keck的近红外高分辨率光谱测量了八个行星质量物体（PMO）的旋转线扩展（1--800 MYR）。将这些速度与已发表的旋转速率相结合，我们编译了27个PMO自旋速度，其中16个源自我们的NIRSPEC/KECK程序。我们的数据与旋转速度$ v $缩放的旋转速度一致，带有行星半径$ r $作为$ v \ propto 1/r $。我们得出的结论是，旋转角动量是保守的，因为对象凉爽并在采样年龄范围内收缩。我们的样品旋转速率中的PMO大约低于其分手值的数量级，这与假设在$ \ Lessim $ \ Lessim $几乎没有Myr的地层时代的磁化范围Bill-PMO磁盘（CPD）旋转。自旋速度有4--5个变化的因素，理论上尚待理解。旋转是否在时标的$ \ gtrsim $ 1 gyr上演变为PMOS还有待观察，就像恒星和高质量的棕色矮人一样，发出磁性的风。
To understand how planetary spin evolves and traces planet formation processes, we measure rotational line broadening in eight planetary-mass objects (PMOs) of various ages (1--800 Myr) using near-infrared high-resolution spectra from NIRSPEC/Keck. Combining these with published rotation rates, we compile 27 PMO spin velocities, 16 of which derive from our NIRSPEC/Keck program. Our data are consistent with spin velocities $v$ scaling with planetary radius $R$ as $v \propto 1/R$. We conclude that spin angular momentum is conserved as objects cool and contract over the sampled age range. The PMOs in our sample spin at rates that are approximately an order of magnitude below their break-up values, consistent with the hypothesis that they were spun down by magnetized circum-PMO disks (CPDs) during the formation era at ages $\lesssim$ a few Myr. There is a factor of 4--5 variation in spin velocity that has yet to be understood theoretically. It also remains to be seen whether spin evolves on timescales $\gtrsim$ 1 Gyr for PMOs, as it does for stars and high-mass brown dwarfs emitting magnetized winds.
