Is there life out there?

CAPE CANAVERAL: Astronomers have found a nearby solar system with seven Earthsized planets, three of which circle their parent star at the right distance for liquid surface water, bolstering the prospect of discovering extraterrestrial life, research published yesterday shows.

The star, known as TRAPPIST1, is a small, dim celestial body in the constellation Aquarius. It is located about 40 light years away from Earth, close by astronomical standards, but about 44 million years away at the average cruising speed of a commercial passenger jet.

Researchers said the proximity of the system, combined with the proportionally large size of its planets compared with the small star, make it a good target for followup studies. They hope to scan the planets’ atmospheres for possible chemical fingerprints of life.

‘‘The discovery gives us a hint that finding a second Earth is not just a matter of if, but when,’’ Nasa chief scientist Thomas Zurbuchen said at a news conference.

The discovery, published in this week’s issue of the journal Nature, builds on previous research showing three planets circling TRAPPIST1. They are among more than 3500 planets discovered beyond the solar system, or exoplanets.

‘‘This is the first time that so many Earthsized planets are found around the same star,’’ lead researcher Michael Gillon, with the University of Liege in Belgium, told reporters.

Researchers have focused on finding Earthsized rocky planets with the right temperatures so that water, if any exists, would be liquid, a condition believed to be necessary for life.

‘‘I think that we’ve made a crucial step towards finding if there is life out there,’’ University of Cambridge astronomer Amaury Triaud said on a conference call with media on Tuesday.

The diameter of TRAPPIST1 is about 8% of the sun’s size. That makes its Earthsized planets appear large as they parade past.

From the vantage point of telescopes on Earth, the planets’ motions regularly block out bits of the star’s light. Scientists determined the system’s architecture by studying these dips.

‘‘The data is really clear and unambiguous,’’ Triaud wrote in an email to Reuters. — Reuters