Count: 0 — No stars meet the criterion when using IAU‑approved proper names (and well‑established traditional names flagged by the IAU) that begin with the letter J. This list applies strict inclusion rules based on the IAU Name Lists, Bright Star Catalogue conventions, SIMBAD identifiers, and common usage in NASA and Gaia references; applying those standards yields no entries. Note an interesting detail: many traditional star names derive from Arabic, Greek, or Latin forms that historically did not use the letter J, so J is unusually rare among officially recognized proper names.

Understand why the criterion produces no results. Classical and medieval source languages did not include a separate letter J, and modern transliteration choices often render original sounds as I, Y, G, or other letters instead of J. The IAU prefers established historical spellings or standardized forms, so anglicized or unofficial spellings that start with J are not adopted as official proper names. Also distinguish proper names from coordinate or survey designations: many catalog identifiers begin with the character “J” (for example, 2MASS or Gaia position-based names like “Jhhmmss.ss±ddmmss.s”), but these are not proper names under the IAU rules.

Consider what comes close and what to do next. Expect to find J‑leading strings only in catalog IDs, modern informal anglicizations, or non‑IAU traditional variants; mark such items clearly as non‑IAU if listed. Consult the IAU Name List, SIMBAD entries, Gaia EDR3 distances, the Bright Star Catalogue, and NASA pages for authoritative naming and data when compiling related pages. Use an A–Z index and per‑letter pages that prioritize IAU‑approved names, and direct readers to adjacent letters or to catalog designations when no proper names exist for a given initial.