heliac英'hiːlɪæk美'hiːlɪæk 基本英英近义反义 adj.与太阳同时出没的¹⁰⁰ Adjective: pertaining to or near the sun; especially the first rising of a star after and last setting before its invisibility owing to its conjunction with the sun;
the heliacal rising of the Dog Star
the heliacal or Sothic year is determined by the heliacal rising of Sothis the Egyptian name for the Dog Star