Yogyakarta Baru was first an independent Earth colony, and later a United Federation of Planets protectorate, that existed from the 22nd to the 24th centuries. (Star Trek: Avenger; Star Trek: Shadowstar Station: "Esteban") It was one of two colonies in the Wolf 359 system, the other being Stapledon Center. (Star Trek novel Federation)
In the 2120s, a scientific team from the American Continent Institute surveyed Wolf-catalogue (i.e., red dwarf) stars within a 5-parsec sphere of the Sol system. The team, led by Esteban Velasco, identified heretofore undiscovered reserves of topaline and pergium on the fifth planet of Wolf 359.
The Yogyakarta Baru colony was established on Wolf-359 V about 2145. (Its founders included Kieran Arismunandar, Julian Bermudo, Victoria Sutomo, and Esteban Velasco.) ("Esteban") The first settlers were mostly those who had lived in the member nation-states of the short-lived Southeast Asian Confederation.
Within three years, the colony was fully self-supporting through the mining of topaline and pergium. For about ten years, the colony practised a policy of isolationism (a difficult task, given that Wolf 359 is about eight light years from Sol) with respect to Earth and its allies until an agricultural plague forced it to accept help. During the Earth-Romulan War, the Yogyakarta Baru military vessel Nasution aided in the defense of Tau Ceti.
In 2264-65, there was an abortive coup d'état. The governor, Indra Kartini Sutomo and her husband were assassinated, and council members and adult members of their families imprisoned, while their children were exiled to the Hamengkubuwono Plains on the other side of the planet. 17 out of the 25 children survived the weeks-long ordeal. The USS Avenger, commanded by Capt. Melissa Sturdevant, later reunited the surviving children with their parents. The Avenger and other Starfleet vessels (including the USS Thermopylae, commanded by Capt. Nikolai Barstow) aided in relief efforts and restoring the legitimate Yogyakarta Baru government. (Star Trek: Shadowstar Station/Star Trek: Avenger: Time, See What's Become of Me)
In the 2340s, geological analyses confirmed that one (perhaps both) of the habitable planets in the Wolf 359 system would explode due to gravitic stresses by the end of the century. Then-extant Federation technology could do nothing to halt the process. The Yogyakarta Baruans redirected much if not all of their efforts to mass migration to Merdeka in the New Colonies territories (Star Trek: Shadowstar Station timeline). The inhabitants of Stapledon Center debated endlessly among themselves; a sizable portion of the populace, however, elected to migrate to other class M worlds, including Al-Jamal and the motherworld, Earth.
By 2360, less than a hundred Yogyakarta Baruans remained on their world. Most had emigrated to Merdeka. On Yogyakarta Baru, Matthew Giordano visited the cemetery where his grandparents and other relatives he had never met were buried. At the Starfleet memorial, he scattered flower petals over the plaque with his mother’s name. (Star Trek: Shadowstar Station: "Mother’s Day”).