It is larger, brighter and more massive than the Sun. It contains about 15 times as much material. It is an aged star, but not really that old. That strange statement needs explaining. Like other stars, Antares formed when a huge cloud of dust and gas became unstable and collapsed under its own gravity.
Stars obtain energy by converting light elements, like hydrogen, into heavier ones.
When, inevitably, they start to run out of fuel, they swell up into red giant stars. This will happen to the Sun in about 5 billion years. What is really interesting is that the more fuel a star starts off with, the faster it uses it up, so that big stars live much shorter lives than smaller ones. Antares is much younger in time than the Sun, but is much older in terms of its life cycle. It will then collapse and explode, and for a few months, outshine all the other stars in our galaxy put together.