Count: 0 — No IAU‑approved or well‑established traditional star names begin with the letter X. This page follows the IAU Name List and major catalogs as the inclusion rule, so the result set is empty. Note that several common star identifiers and Greek‑letter designations begin with the character X when transliterated (for example, the Bayer designation “Xi”), but those are labels, not proper names.

Note that historical naming traditions drive this absence. Many classical star names come from Arabic, Latin, and Greek roots that rarely start with an X sound in Latin script. The IAU approves names that show long‑standing cultural use or clear historical provenance, and very few traditional names begin with the Latin letter X. Also note that modern transliterations from languages such as Chinese sometimes start with X in pinyin, but those names must meet IAU criteria for approval and widespread use before they qualify as proper names.

Consider the things that do come close. Treat Bayer designations like Xi (ξ) and variable‑star labels such as X Aur as systematic identifiers rather than proper names. Expect many catalog entries and survey identifiers that start with X (X‑ray sources, mission codes, catalogue prefixes) — these are technical IDs, not traditional names. Consult the IAU Name List, SIMBAD, and major catalogs for adjacent categories (Bayer names, Flamsteed numbers, catalog identifiers) or for approved names under other letters in the A–Z index.