Can I read Limits on the Spin-Orbit Angle and Atmospheric Escape for the 22 Myr-old Planet AU Mic b on EtoBox?

Limits on the Spin-Orbit Angle and Atmospheric Escape for the 22 Myr-old Planet AU Mic b by Hirano, Teruyuki; Krishnamurthy, Vigneshwaran; Gaidos, Eric; Flewelling, Heather; Mann, Andrew W.; Narita, Norio; Plavchan, Peter; Kotani, Takayuki; Tamura, Motohide; Harakawa, Hiroki; Hodapp, Klaus; Ishizuka, Masato; Jacobson, Shane; Konishi, Mihoko; Kudo, Tomoyuki; Kurokawa, Takashi; Kuzuhara, Masayuki; Nishikawa, Jun; Omiya, Masashi; Serizawa, Takuma; Ueda, Akitoshi; Vievard, Sébastien is a scholarly article available to read on EtoBox.

What is Limits on the Spin-Orbit Angle and Atmospheric Escape for the 22 Myr-old Planet AU Mic b about?

We obtained spectra of the pre-main sequence star AU Microscopii during a transit of its Neptune-sized planet to investigate its orbit and atmosphere. We used the high-dispersion near-infrared spectrograph IRD on the Subaru telescope to detect the Doppler "shadow" from the planet and constrain the projected stellar obliquity. Modeling of the observed planetary Doppler shadow suggests a spin-orbit alignment of the system ($\lambda=-4.7_{-6.4}^{+6.8}$ degrees), but additional observations are needed to confirm this finding. We use both the IRD data and spectra obtained with NIRSPEC on Keck-II to search for absorption in the 1083 nm line of metastable triplet He I by the planet's atmosphere and place an upper limit for the equivalent width of 3.7 m\AA at 99 $\%$ confidence. With this limit and a Parker wind model we constrain the escape rate from the atmosphere to $<0.15-0.45\, M_{\oplus}$ Gyr$^{-1}$, comparable to the rates predicted by an XUV energy-limited escape calculation and hydrodynamic models, but refinement of the planet mass is needed for rigorous tests.

Author

Hirano, Teruyuki; Krishnamurthy, Vigneshwaran; Gaidos, Eric; Flewelling, Heather; Mann, Andrew W.; Narita, Norio; Plavchan, Peter; Kotani, Takayuki; Tamura, Motohide; Harakawa, Hiroki; Hodapp, Klaus; Ishizuka, Masato; Jacobson, Shane; Konishi, Mihoko; Kudo, Tomoyuki; Kurokawa, Takashi; Kuzuhara, Masayuki; Nishikawa, Jun; Omiya, Masashi; Serizawa, Takuma; Ueda, Akitoshi; Vievard, Sébastien

Published

2020

Language

EN