Not at all Sad: The Heritage of Arabian Astronomy’s Auspicious Asterisms — from Sadachbia to Sadalsuud

The region of sky spanning Capricornus, Aquarius, and western Pegasus contains a large number of third-magnitude stars, many of which bear names—approved by the IAU Working Group on Star Names—that reflect a common origin in indigenous Arabian astronomy. Although only a few of these Arabic-derived star names in use today begin with the prefix “Sad-“, each of these stars formerly belonged to Arabian asterisms that bore formulaic Arabic names that began with the term saʿd, which indicated something auspicious, commonly a star or asterism. These formulaic star names—known collectively in Arabic as “the Auspicious Asterisms” (as-suʿūd)—appeared in this particular region of sky alone, and the resulting collection of ten asterisms (mostly pairs of stars) rose heliacally within the space of just five weeks, from mid-January to mid-February, as viewed from Arabia in the 9th century CE.

Drawing from 9th and 10th century CE Arabic texts by Quṭrub (d. 821 CE), Ibn Qutayba (d. 889 CE), and aṣ-Ṣūfī (d. 986 CE), this talk reveals the unique heritage of indigenous Arabian astronomy in this region of the sky. The research begins by locating the group of ten asterisms in the modern sky and connecting the roots of their Arabic names to the vestiges that remain in modern star catalogues. The researcher then examines the seasonal significance of these Auspicious Asterisms (as-suʿūd) within Arabian culture during the first millennium CE, including the use of rhymed prose that had become attached to four of the ten asterisms to tie their heliacal risings to the meteorological and cultural happenings of Arabian winters. The results of this original research demonstrate the historical significance of these stars names that continue in use today.