...Plus protomatter and who-knows-what.
Dax: "Looks like someone's been doing some modifications to the Yukon. I'm also picking up large amounts of trilithium, tekasite, and protomatter on board."
Kira: "A bomb. If it explodes inside the sun- "
Dax: "It could trigger a supernova."
This of course assuming that there ever even was a bomb aboard. Or a Changeling. After all, the true tactical function of the seeming nova-bombing run in the end was to create a diversion so that the Dominion fleet could slip in through the jammed-open wormhole unchallenged. A smart Changeling would just send a decoy towards the Bajoran sun, transmitting the fake signatures of a potent bomb (easier to come by than an actual bomb) and, of course, a Changeling, while making a clean getaway and laughing at the Federation, Klingon and Romulan starships scrambling out of the way of the imagined explosion.
Doesn't change the fact that Dax and Kira seemed to think
a cocktail of trilithium, tekasite and protomatter would cause a supernova explosion in a neat and tidy main sequence star.