Bodies That Collide by Meg J. Hall

What happens when two stars collide?

For nine years, Seraphina Darling and her brother Jacks have been in foster care following the death of their parents. When Sera stops her foster father from laying hands on Jacks, the siblings are sent back to where it all began. Before setting out to their new foster home, Sera receives a letter stating there is more to her parents death than she previously thought.
With the help from a mysterious boy at school, Sera digs deeper into the cryptic letter about her parents demise. Yet, the more she learns the stickier her past becomes. With each new lead pointing down a darker path, Sera becomes unsure of who she can trust, including herself.

The truth does not always set us free, sometimes it drags us down with it.