Triple sunrises, sunsets at this strange new world

All three stars rotate around the system’s center of mass, according to researchers.

A newly discovered planet has been spotted orbiting three stars at once, in a highly exotic celestial arrangement. “But this planet is about a third of the way in between the stars”.

Wagner and his team were able to directly image HD 131399Ab using a combination of techniques known as adaptive optics and coronagraphs.

Here we are, standing on a distant moon. It all worked out just right so that the pair of suns don’t introduce too much light on the exoplanet, giving astronomers the ability to image the alien world directly. In contrast, we discovered HD 131399Ab via imaging, which means that we immediately have more data on its atmospheres than on the vast majority of other exoplanets.

As a result of this complex configuration, the Jupiter-like world doesn’t orbit all three stars; it orbits only HD 131399A. That’s because the monster-sun is rising from one horizon as the smaller two suns are setting at the other. The other two stars, twirling around each other, lie outside the planet’s orbit and also circle the dominant central star, which is thought to be 80% more massive than the Sun.

All three stars are visible in the sky of the exoplanet for about half of its 550-year orbit. “But with more possible planet candidates in sight, we will have to change this soon”.

A University of Arizona-led team used a telescope in Chile to spot this odd new world 320 light years away.

Such binary solar systems may be relatively common in the universe, but experts say those involving three stars or more are rare. SPHERE is more direct. It’s created to filter out the bright light of a host star (or three), allowing scientists to directly detect these infant worlds. SPHERE is sensitive to infrared light, allowing it to detect the heat signatures of young planets, along with sophisticated features correcting for atmospheric disturbances and blocking out the otherwise blinding light of their host stars.

Considering astronomical distances, the planet HD131399Ab is not too far from us.

He can tell you, for instance, how the biggest of the three suns up ahead is eight times more luminous than the sun we know on Earth-but that it doesn’t appear as bright since it’s much farther away from this planet than the Earth’s sun.

Kevin Wagner, who is a PhD student at the University of Arizona, identified the planet among hundreds of candidate planets and led the follow-up observations to verify its nature. “However, the planet is still very hot from its formation – the surface that we see is over 1,000 degrees Fahrenheit, and even hotter at lower layers, and that’s lasted for the planet’s ~16 million-year lifetime!” That was number four.

Compared to planets in other multiple-star systems, the newly discovered planet has a much wider orbit-meaning that it’s a lot farther from its main sun.

Scientists who made the discovery were surprised that such a world could survive at all. Scientists expect that planets in triple-star systems don’t stick around very long because as their distance from the stars changes, so does the strength of the radiation and gravity they experience. That would provide planet-wide endless daytime.

Wagner is continuing to refine HD 131399Ab’s orbit to determine whether the planet will be stable over the long-term. It’s good we’re standing on this moon, in other words.