Red giants come into being when a star's core becomes depleted of hydrogen. AFAIK there is no "real science" method to speed up the process, as it's directly coupled to the rate at which the star is consuming fuel; the rate the star consumes fuel is coupled to the star's mass.

An in-universe method of sciency technobabble tech could do it, depending on what exactly you have planned for your story.

Issac Asimov's story "The Last Question" eventually uses the concept of "sunpower units." I'd always imagined these as some sort of power station drawing off the helium of the star and fusing it as fast as possible.

If it works in your story, it might be an interesting story hook if the Sun was used as a fueling depot by some alien species, who used hyperspace/subspace to extract hydrogen from the core. Maybe they need to draw it from the core so they can have the fuel at the right temperature, which would explain why they're not just "scooping it" off the surface. This goes on for a while until the solar system is finally flagged as "inhabited," but by that point the damage had been done, and in a few ten thousand years the sun baloons out into a red dwarf.

If you want to give humanity the technology you can do that as well. The thing to note is that you need to use some technology to pull the helium FROM THE CORE. Pulling it from the surface won't make a difference, as surface helium doesn't get burned until way late in the sequence. Sure, it reduces the lifetime of the star, but wouldn't affect the burning rate.

If you can artificially reduce the helium in the core, maybe even have whoever is doing it dumping trash hydrogen or carbon and iron in there, you could nudge the star along the main sequence.

The only other thing I'd point out is whatever you do to the Sun you have to have MASSIVE tech to pull it off. There are 5 billion years of fuel in the core, and the sun is burning ~600 million TONS of hydrogen to helium every SECOND. In order to burn out the sun, you'll need something that can eat up 2-10x that fuel.

Smashing another sun into the Sun won't make it burn off faster, it'll actually top it off. Having a binary style star show up wouldn't work, because it draws fuel off the surface (and would cause more harm elsewhere).

If you don't want some kind of alien tech, a "realistic" sounding idea to me is having a black hole migrate into the core. It would soak up fuel while also increasing the gravity within the core. This might work in causing the hydrogen to ignite, but I'm pretty sure any black hole big enough to do this would cause other gravitational problems to the solar system. Also, I'm not a nuclear physicist, so Stephen Hawking might have problems with this suggestion.

Red giants come into being when a star's core becomes depleted of hydrogen. AFAIK there is no "real science" method to speed up the process, as it's directly coupled to the rate at which the star is consuming fuel; the rate the star consumes fuel is coupled to the star's mass.

An in-universe method of sciency technobabble tech could do it, depending on what exactly you have planned for your story.

Issac Asimov's story "The Last Question" eventually uses the concept of "sunpower units." I'd always imagined these as some sort of power station drawing off the helium of the star and fusing it as fast as possible.

If it works in your story, it might be an interesting story hook if the Sun was used as a fueling depot by some alien species, who used hyperspace/subspace to extract hydrogen from the core. Maybe they need to draw it from the core so they can have the fuel at the right temperature, which would explain why they're not just "scooping it" off the surface. This goes on for a while until the solar system is finally flagged as "inhabited," but by that point the damage had been done, and in a few ten thousand years the sun baloons out into a red dwarf.

If you want to give humanity the technology you can do that as well. The thing to note is that you need to use some technology to pull the helium FROM THE CORE. Pulling it from the surface won't make a difference, as surface helium doesn't get burned until way late in the sequence. Sure, it reduces the lifetime of the star, but wouldn't affect the burning rate.

If you can artificially reduce the helium in the core, maybe even have whoever is doing it dumping trash hydrogen or carbon and iron in there, you could nudge the star along the main sequence.

The only other thing I'd point out is whatever you do to the Sun you have to have MASSIVE tech to pull it off. There are 5 billion years of fuel in the core, and the sun is burning ~600 million TONS of hydrogen to helium every SECOND. In order to burn out the sun, you'll need something that can eat up 2-10x that fuel.

Smashing another sun into the Sun won't make it burn off faster, it'll actually top it off. Having a binary style star show up wouldn't work, because it draws fuel off the surface (and would cause more harm elsewhere).

If you don't want some kind of alien tech, a "realistic" sounding idea to me is having a black hole migrate into the core. It would soak up fuel while also increasing the gravity within the core. This might work in causing the hydrogen to ignite, but I'm pretty sure any black hole big enough to do this would cause other gravitational problems to the solar system. Also, I'm not a nuclear physicist, so Stephen Hawking might have problems with this suggestion.