Spitzer Variability Properties of Low-gravity L Dwarfs
Spitzer Variability Properties of Low-gravity L Dwarfs
复制标题
低重力 L 矮星的斯皮策变异特性
作者：
J. Vos;B. Biller;K. Allers;J. Faherty;Michael C. Liu;S. Metchev;S. Eriksson;E. Manjavacas;T. Dupuy;M. Janson;Jacqueline Radigan;I. Crossfield;M. Bonnefoy;W. Best;D. Homeier;J. Schlieder;W. Brandner;T. Henning;M. Bonavita;E. Buenzli
我们介绍了斯皮策太空望远镜对三颗低重力L型矮星的变率监测观测，这些矮星具有以前在近红外波段探测到的变率：2 MASS J 0045 +16，2 MASS J 0501 −00和2 MASS J1425−36。我们在两个目标2 MASS J 0045 +16和2 MASS J 0501 −00中检测到显著的周期性变化。我们没有检测到2 MASS J1425−36的变异性。结合我们新的自转周期和自转速度，我们计算出2 MASS J 0045 +16、2 MASS J 0501 −00和2 MASS J1425−36的倾角分别为22° ± 1°、和。我们的三个新对象是一致的倾斜，振幅和颜色异常之间的初步关系，以前报道的。具有最高变化幅度的物体倾斜赤道，而最大观测幅度随着倾斜角度的减小而减小。我们还发现了倾斜角和颜色异常之间的相关性与测量倾斜的对象的样本。编译整个样本的棕矮星与斯皮策变异检测，我们发现没有增强振幅的年轻，早期的L型矮星相比，外地的侏儒人口。在4.5 μm处，低重力L-L型矮星的振幅有可能增强。我们没有发现振幅比和光谱类型之间的相关性领域的矮星或年轻的人口。最后，我们编译了一个大样本的棕矮星的旋转周期与年龄1万年-1 Gyr和比较旋转速率的演化模型预测假设角动量守恒。我们发现，当前样本的棕矮星的自转速率落在进化模型和分裂极限所设定的预期范围内。
We present Spitzer Space Telescope variability monitoring observations of three low-gravity L dwarfs with previous detections of variability in the near-IR: 2MASS J0045+16, 2MASS J0501−00, and 2MASS J1425−36. We detect significant periodic variability in two of our targets, 2MASS J0045+16 and 2MASS J0501−00. We do not detect variability in 2MASS J1425−36. Combining our new rotation periods with rotational velocities, we calculate inclination angles of 22° ± 1°, , and for 2MASS J0045+16, 2MASS J0501−00, and 2MASS J1425−36, respectively. Our three new objects are consistent with the tentative relations between inclination, amplitude, and color anomaly previously reported. Objects with the highest variability amplitudes are inclined equator on, while the maximum observed amplitude decreases as the inclination angle decreases. We also find a correlation between the inclination angle and color anomaly for the sample of objects with measured inclinations. Compiling the entire sample of brown dwarfs with Spitzer variability detections, we find no enhancement in amplitude for young, early-L dwarfs compared to the field dwarf population. We find a possible enhancement in amplitude of low-gravity late-L dwarfs at 4.5 μm. We do not find a correlation between amplitude ratio and spectral type for field dwarfs or for the young population. Finally, we compile the rotation periods of a large sample of brown dwarfs with ages 1 Myr–1 Gyr and compare the rotation rates predicted by evolutionary models assuming angular momentum conservation. We find that the rotation rates of the current sample of brown dwarfs fall within the expected range set by evolutionary models and breakup limits.
WASP-21b：一颗热土星系外行星凌日厚盘状恒星
影响因子：
6.5
作者：
Bouchy F
通讯作者：
Bouchy F
年轻的多云 L 矮星伴星 VHS J1256–1257 b 的强烈近红外光谱变化
DOI：
10.3847/2041-8213/ab8197
发表时间：
2020
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Bowler, Brendan P.;Zhou, Yifan;Morley, Caroline V.;Kataria, Tiffany;Bryan, Marta L.;Benneke, Björn;Batygin, Konstantin
通讯作者：
Batygin, Konstantin
影响因子：
6.5
作者：
Baraffe, Isabelle;Homeier, Derek;Chabrier, Gilles
通讯作者：
Chabrier, Gilles