Sun is about 150 million km's away from the earth. It is about 5726°C. Did you know that a space suit offers a heat resistant of only about 248°C. If an astronaut were to go to an area which is way more hotter than his suit that could provide him resistance, he would get dehydrated and probably pass out. As we near the sun, the heat radiations are more, thereby increasing its temperature. However it is found that one can reach up to 2-3million km near the sun.