⪅

Symbol

 * 1) less than an approximate value.
 * 2) * 2015, Colin Goldblatt, Habitability of Waterworlds: Runaway Greenhouses, Atmospheric Expansion, and Multiple Climate States of Pure Water Atmospheres, Astrobiology. 2015 May 1; 15(5): 362–370:
 * The states are as follows: globally ice covered (Ts⪅245 K), cold and damp (270⪅Ts⪅290 K), hot and moist (350⪅Ts⪅550 K), and very hot and dry (Ts⪆900 K). No stable climate exists for 290⪅Ts ⪅350 K or 550⪅Ts⪅900 K.