Observational evidence for rotational desorption of Complex Molecules by
  radiative torques from Orion BN/KL
  Complex Organic Molecules (COMs) are believed to form in the ice mantle of
dust grains and are released to the gas by thermal sublimation when grain
mantles are heated to temperatures of $T_{\rm d}\gtrsim 100\,\rm K$. However,
some COMs are detected in regions with temperatures below 100 K. Recently, a
new mechanism of rotational desorption due to centrifugal stress induced by
radiative torques (RATs) is proposed by Hoang & Tram 2020 that can desorb COMs
at low temperatures. In this paper, we report observational evidence for
rotational desorption of COMs toward the nearest massive star-forming region
Orion BN/KL. We compare the abundance of three representative COMs which have
very high binding energy computed by the rotational desorption mechanism with
observations by ALMA, and demonstrate that the rotational desorption mechanism
can explain the existence of such COMs. We also analyze the polarization data
from SOFIA/HAWC+ and JCMT/SCUBA-2 and find that the polarization degree at
far-infrared/submm decreases with increasing the grain temperature for $T_{\rm
d}\gtrsim 71\,\rm K$. This is consistent with the theoretical prediction using
the Radiative Torque (RAT) alignment theory and Radiative Torque Disruption
(RATD) mechanism. Such an anti-correlation between dust polarization and dust
temperature supports the rotational disruption as well as rotational desorption
mechanism of COMs induced by RATs.
