**3.3 CH3OH**

α-CH3OH is a thermodynamically stable phase of solid CH3OH at temperatures < 157 K under low pressure [41]. Torrie et al. [22] showed by neutron diffraction that α-CH3OH is chiral, including the positions of the hydrogen atoms (space group: *P*212121). Furuya et al. [23] observed the deposition of CH3OH on a-H2O using TEM between 90 and 120 K and found that α-CH3OH was formed at temperatures >100 K; however, they did not observe the crystallization of amorphous CH3OH (a-CH3OH). Using TEM, we observed the formation of α-CH3OH crystals during the warming of a-CH3OH deposited on a-H2O (**Figure 5**). Therefore, we concluded that if α-CH3OH crystals were formed by the heating of a-CH3OH on a-H2O grains in young stellar objects (i.e., protoplanetary disks), α-CH3OH were/are chiral.

Sugisaki et al. [42] observed by calorimetry that the glass transition and crystallization of glassy CH3OH occurred at about 103 and 105 K, respectively. Luna et al. [14] also observed by IR spectroscopy that the crystallization temperature of a-CH3OH is between 100 and 110 K.
