@Curious Catfish theres actuially a semi-canon moon with that name lol. can i help with ur fanfic it sounds quite interesting

Yeah. you can help.

Ok maybe there's somehing dark about thee creation of that planet,

There's already a dark origin. (See A New Hope for details.)

No but like a planet popping out of no where, maybe some sith power or some hidden energy

Or a cloaking device

Darth Vader muses in the Star Wars novel (pg. 106 in my ©1993 ed.) that the most powerful destructive machine ever constructed had no influence on the Alderaan star system—that it would take a micro-breakdown on that section of map to see the "slight reduction in spatial mass" caused by the disappearance of the planet. "The actions of mankind remained unnoticeable to an uncaring, unimaginably vast universe."

Ground your story's setting in physical reality and focus on the plot as not to require heaps of exposition unless the appearance of the planet itself is intrinsic to the plot.

Given the time period of your story, Planet Organa (bleah... go with Thul to spice things up: who says Alderaanians all had to bow to House Organa?) could be a rouge planet, dwarf planet, or some other astronomical object that did eventually respond to the orbital disturbance.

@Oddly Salacious But the Alderaanians had a good life, they would be happy with their government.

The OP states that these are two ex-Alderaanians visiting the Alderaanian Graveyard 100 years after the Battle of Yavin. They could be a long-lived species who were exiled from the planet prior to its destruction. These Alderaanians might not have had a good life and have come to resent House Organa (perhaps even Bail and Breha themselves) for their plight. It would establish a good plot twist to hook the reader.

There's not much in the Wook canon about the Alderaanian government, but contempt did exist to the point that some left the planet in disgust.

Long-lived Humans?

I establish some humans having longer lifespans than the average (or median) given the human characteristic to adapt to environmental pressures over time. Leia Organa Solo was not Alderaanian-human. Therefore, she might have died naturally twenty-odd years prior to this story had she not played Superwoman in Space. On the other hand, I read once that Han Solo was much older than what was listed as his age—that the smuggler/ thief/ insurrectionist lied about his background isn't a hard stretch. The only other Corellian I can recall is Crix Madine, and his reported death also shortened his life.

Okay.