This is a book I read (listened to?) around 2007. I don't remember a cover; it may have been an audiobook, but I can't find it in my Audible library.
A ship is traveling away from Earth at relativistic speeds. Navigation / maintenance of speed requires constant intervention by a few people on board who have some sort of special mental / extrasensory capability; they work in shifts. Some people on board (the navigators themselves ? not sure) maintain a mental link with their identical twins who have remained back on Earth.
Earth is destroyed when the Sun explodes. The twins on board see the event and feel their siblings dying, and one of them commits suicide, which makes navigation too exhausting for the remaining crew and leads to the ship slowing down and being unable to complete its journey in a reasonable time: the crew will die in space.
Another ship from Earth, apparently FTL and developed after their departure, catches up with them. It turns out that the Sun's destruction was not a natural event, but was caused by some unknown entity. Having no home to come back to, they decide to identify and hunt down whoever destroyed the Sun. (End of this book, don't know about a sequel.)
The writing was modern and not youth-oriented. The story was pretty strict about time dilation, though I don't remember if the telepathy between twins was instantaneous or limited to light speed. The entire story was told from the point of view of the ship's crew. The crew was mixed-gender, with at least one couple.