A literal ton wouldn’t do anything measurable but yeah, adding more material of lower atomic numbers would in theory work considering it’s a fusion engine and wouldn’t exactly scoff at having to break the water molecule before using it.
Edit: like maybe if there was a star with a bunch of particularly wet planets around it and you somehow deorbited them, since as far as I’m aware the elements heavier than iron are just dead weight, they wouldn’t put out the star or anything.
I mean, if you add enough iron I believe it would eventually disrupt fusion, but you’d need an incredible amount, far more than you’d ever get from orbiting planets.
Stars have a lot of mass. The Sun loses almost 5 billion tons of mass every second and has enough fuel to last another 4-5 billion years. Adding a single ton of anything would make no appreciable difference. If you were to drop Jupiter into the Sun, it would have an effect, but Jupiter is only 0.09% the Sun’s mass, so the effect would be small.
https://www.astronomy.com/science/ask-astro-could-jupiter-ever-become-a-star/
Depending on how you define a star, you could smush ~13 Jupiters together and make something that is maybe a star. To make a definite star you need ~80 Jupiters. To make it the same size as our Sun you’d need almost 250 Jupiters.
