Rigel IV

Rigel IV was the inhabited fourth planet of the Rigel system, less than ninety light years away from Earth. The planet was the homeworld to the Rigel IV natives, including the, and had deposits of boridium and murinite. 

History
Humans began moving to Rigel IV after 2156. 

In 2266, the Redjac entity possessed Hengist, a native of Rigel IV, and killed several women on the planet. He was never caught and was only known as "Beratis". On Argelius II, Redjac committed a murder with a knife from Rigel IV's Argus River region. 

In the 24th century, a brilliant astronomer with a fondness for the Betazoid Ambassador Lwaxana Troi resided on Rigel IV. He named a star after Lwaxana, or so she claimed in 2367. 

In mid-2370, Rigel IV hosted a nearly week-long conference on hydroponics attended by Keiko O'Brien. 

Rigel IV was also the site of a pergium refinery. During the Dominion War, a shipment of pergium en route to Rigel IV from the Sappora system had been destroyed by the Jem'Hadar. 

Background information
According to StarTrek.com, Rigel IV was a M-class world.

Evidence for the statement that Rigel IV is less than ninety light years from Earth is specifically that, in "Two Days and Two Nights", the  sets a milestone several months after undertaking a mission to Rigel X (which it visits in ENT pilot episode ) by becoming the first Earth ship to travel ninety light years away from the Sol system.

A question, which was not seen on screen, from Spock's memory test in established that Rigel IV at one point signed a peace treaty with. The treaty was important because it set a legal precedent that, "All beings may not be created equal yet shall be given equal opportunity and treatment under the law."

According to Star Trek: Star Charts (pp. 52, 59, "United Federation of Planets I"), Rigel IV, also known as Beta Rigel IV, was an M-class planet. The planet was a member planet of both the United Rigel Colonies and the United Federation of Planets. Rigel IV was admitted, along with the United Rigel Colonies, to the Federation in 2202.