Disclaimer : I'm working on the entire pseudo-science thing , so the scientific part of this whole thing isn't made up properly... Certain things have not been explained , this is to keep the post short. Also I apologize if I haven't provided any necessary info or if I have broken any guidelines as this is my first post. I realize how this topic could be quite broad. Hence I've given a list of things that are necessary in an answer at the end.
Scenario : Okay. So here is the background, in the future, a well 200 years or so later, time travel is being developed. The solar system is the only known place in the universe with life. This is restricted to Earth, Mars, Titan and a myriad of larger, sometimes grouped asteroids...
Now the event in focus is time travel experiments which are achieved by a fictional subatomic process to create a wormhole. These experiments are being performed in the outer fringes of the asteroid belt, away from major settlements, as a safety precaution. The time travel works for small massed objects, and trials with life is considered to be too hazardous. The scientists decide to try their experiment with a huge mass object and thus they choose a nearby asteroid for insertion.
The asteroid is inserted into the portal and just before it goes into the portal, the asteroid splits into two segments. Now this method of time travel is still being worked upon, the scientists know that the objects they send in are being sent back into the past... But, they don't know the destination. So, just before the asteroid goes in, it splits into two and one part gets sent back to the past, a little after the formation of animal life on Earth and one part gets sent a little later , to the time of Dinosaurs and it hits the earth , wiping out all larger forms of life.
The scientists are completely oblivious to all of this.. But what they do realize is that insertion into the portal irradiates the inserted object , with an energy equivalent to the mass of the object. Subsequently the experiments are banned and the off-world experimentation site is closed down.
Now back to the part that the scientists don't know. The second segment to enter the portal was responsible for the extinction of the dinosaurs and all other large reptiles... This is timeline 1, where events as we know happen and this is where eventually the time-travel dabbling scientists help create the timeline in a everlasting circle of sorts.
The first segment is more interesting. This piece of the asteroid was significantly larger than the the other one, and collides into the Sun , disrupting the fusion process inside the sun and causing the 'transformation' of hydrogen into something else, caused by the subatomic differences in the asteroids makeup. All the 'polluted matter' of the Sun splits away from the original and creates a small , more-powerful star that orbits the sun, that emits a greater part of the electromagnetic spectrum and bombards the solar system with radiation. This is timeline 2.
Now The Questions : How would the life on Earth be affected ? Plant life already exists , but most would begin mutate to the new environment. The primary life is reptilian..... Assuming that due to the exposure the life forms have gained the potential for greater intellect what types of creatures would be produced ? What of their society ? Peaceful hunter-gatherers or Tribal fighters ? How would the earth be affected in terms of meteorology and geography ?