The discovery of a giant planet closely orbiting another star adds new clues to one of the hottest topics in astronomy — how solar systems form.

The finding, using the Canada-France-Hawaii telescope atop Mauna Kea, supports one of the competing ideas of the genesis of so-called “hot Jupiters,” gas giants that are near their host star.

Astronomers were startled to find, in 1995, gas giants in close proximity to their stars, because that is not the case in our own planetary system. Jupiter, Neptune and Uranus are all far from the sun, while smaller, rocky planets occupy the solar system’s inner reaches.

So, they figured, hot Jupiters either achieved their close-in orbits early or gradually over the course of time.

The latest evidence, described in the current issue of the journal Nature, supports the first scenario because the planet orbits a star, V830 Tau, that is very young, the scientists say,

The star, 430 light-years away in the constellation Taurus, is only 2 million years old, compared with 4.5 billion for our own, middle-aged sun.

“Our discovery demonstrates for the first time that such bodies can be generated at very early stages of planetary formation, and likely play a central role in shaping the overall architecture of planetary systems,” said Jean-Francois Donati, an astronomer with the Canadian National Center for Scientific Research, in a statement Wednesday. Donati is the lead author of the Nature paper.

In a telephone interview Wednesday from Hawaii island, Claire Moutou, another member of the team, said gas giants cannot form close in because the sun’s magnetic field keeps the planetary building blocks at bay.

Astronomers detect most extrasolar planets, or exoplanets, by looking for minute dips in the brightness of stars, which indicates that a planet is transiting, or passing in front of it, from our perspective.

In this case, the research team found a regular 4.9-day “wobble” in the velocity of the host star that revealed the gravitational tug of a giant planet almost as massive as Jupiter.

The planet is only 4.6 million miles from the star, or about 5 percent of the distance from Earth to the sun.

Key to the discovery were twin instruments called spectropolarimeters, one on the Canada-France-Hawaii telescope and a second on a smaller telescope in the French Pyrenees, a range of mountains bordering Spain.

“Planet formation models offer two competing explanations of how and when this migration of hot Jupiters occurred,” said Clement Baruteau, another member of the research team. “Either it happened early while these planets were still forming, or much later, with some planets being kicked closer to their stars due to the interaction of multiple planets, or both. Our discovery demonstrates that the first, earlier option is taking place.”

Among the known hot Jupiters, some have strongly tilted or even upside-down orbits, suggesting they were knocked into close orbits by interactions with other planets or neighboring stars.

On Monday, Caltech astronomers using the Keck Observatory on Mauna Kea announced the discovery of another giant planet, K2-33b, very near its host star, 5 million to 10 million years old. That also was published in Nature.

On May 26, astronomers using two Mauna Kea observatories, the Keck II and the NASA Infrared Telescope Facility, announced they had found a planet, Cl Tau b, eight times larger than Jupiter, in close orbit around its 2 million-year-old star. The star is 450 light-years away, also in Taurus.

“For decades, conventional wisdom held that large Jupiter-mass planets take a minimum of 10 million years to form,” said Rice University astronomer Christopher Johns-Krull, lead author of that study, published in the Astrophysical Journal. “That’s been called into question over the past decade, and many new ideas have been offered, but the bottom line is that we need to identify a number of newly formed planets around young stars if we hope to fully understand planet formation.”