A second planet has been discovered circling Beta Pictoris, a fledgling star in our own galaxy offering astronomers a rare glimpse of a planetary system in the making, according to a study published Monday.

“We talking about a giant planet about 3,000 times more massive than Earth, situated 2.7 times further from its star than the Earth is from the Sun,” said Anne-Marie Lagrange, an astronomer at France’s National Centre for Scientific Research and lead author of a study in Nature Astronomy.

The new planet, b Pictoris c, completes its orbit roughly every 1,200 days. Like its big sister b Pictoris b, discovered by Lagrange and her team in 2009, it is a gassy giant.

Visible with the naked eye, Beta Pictoris — with a mass nearly twice that of the Sun — is a newborn by comparison: only 23 million years old.

The Sun is more than 4.5 billion years old.

It is also relatively nearby, just over 63 light years, and surrounded by a disk of stellar dust, according to a report by AFP.

“To better understand the early stage of formation and evolution, this is probably the best planetary system we know of,” Lagrange said.

By Lucia Binding, news reporter

“I promise not to do this to Greenland!”, the US president joked on Twitter.

Mr Trump acknowledged on Sunday that he was “strategically” interested in such a deal, but said it was not a priority of his administration.

He told reporters: “It’s not number one on the burner.”

Following his remarks, Danish prime minister Mette Frederiksen said that Greenland was not for sale and that Mr Trump’s idea of buying it is “an absurd discussion”.

“Greenland is not Danish. Greenland is Greenlandic,” she said.

Ms Frederiksen added that she hopes “that this is not something that is seriously meant”.

Mr Trump’s interest in the Danish territory emerged last week when he reportedly discussed it in a private meeting with advisers.

Danish politicians poured scorn on the idea, with former prime minister Lars Lokke Rasmussen describing it as an “April Fool’s Day joke”.

However, that didn’t not appear to have put off Mr Trump.

Speaking to reporters in New Jersey, he said: “It is something we talked about. Denmark essentially owns it, we are very good allies with Denmark, we protect Denmark like we protect large portions of the world.

“The concept came up – strategically it would be interesting. We’ll talk to them a little bit, it is not number one on the burner at the minute, I can tell you that.

“A lot of things could be done, essentially it is a large real estate deal. It’s hurting Denmark very badly because they are losing almost $700m a year carrying it.”

America has had an air base in Greenland for decades as part of its global network of missile radars and space surveillance.

Mr Trump, who is due to visit Denmark in September as part of a European trip, is not the first US president to raise the idea of purchasing the island.

In 1946, president Harry Truman offered to buy Greenland for $100m (£82.4m).

The island’s foreign ministry tweeted on Friday: “#Greenland is rich in valuable resources such as minerals, the purest water and ice, fish stocks, seafood, renewable energy and is a new frontier for adventure tourism.

“We’re open for business, not for sale.”

Greenland, a self-ruling part of Denmark, is dependant on Danish economic support and is situated between the North Atlantic and Arctic oceans.

It handles its own domestic affairs, while Copenhagen oversees its defence and foreign policy.

The president’s intentions emerged last week when he reportedly discussed buying the Danish territory in a private meeting with advisers.

So, why would Mr Trump want to buy Greenland, and what do we really know about it?

:: It’s untapped

Greenland’s ice sheet is melting. And quickly.

The land is thought to be rich in gold, rubies, diamonds, coppers, olivine, marble and oil.

The rapidly melting ice means previously out-of-reach energy and minerals are now more accessible.

China has shown an interest in recent years too…

:: For his legacy?

Mr Trump might think it would be pretty cool to buy Greenland.

Former US president Harry Truman offered to buy it in 1946 so Mr Trump would probably like to be the one to pull it off.

But it seems unlikely.

:: ‘It would be nice’

Mr Trump’s own words.

When asked about reports that he was exploring the purchase of the 850,000 square mile island from Denmark, the US president said he was “looking at it” as “strategically for the US it would be nice”.

:: To do Denmark a favour?

The president has suggested he has Denmark’s best interests at heart by wanting to buy Greenland.

He said: “A lot of things could be done, essentially it is a large real estate deal. It’s hurting Denmark very badly because they are losing almost $700m a year carrying it.”

:: How much would it cost?

President Truman offered $100m for it in 1946 – which in today’s money would be about $1.3bn.

:: What else do we know about Greenland?

Population: It’s home to 56,000 people. Greenlanders call themselves “Kalaallit” and are an indigenous Inuit people. Inuit means “human being” or “people”. According to Greenland’s government, the indigenous Inuit people make up 85% of the population – the rest are primarily Danes.

The land: It’s officially the world’s largest island that’s not a continent. About 80% of Greenland is covered by ice and snow. People mostly live in the 20% of the country that isn’t – mainly on the coast.

Weather: Average temperatures rarely exceed 10C (50F) during the summer, and that’s usually just in July – the only month when the temperature reaches above freezing. The longest day of the year is 21 June – which is also a national holiday. Donald Trump’s birthday is on 14 June so maybe he’d make it a week-long celebration. The nation celebrates on 21 June because that’s the day the flag received its official introduction in 1985.

Speaking of flags: The white half of the flag symbolises Greenland’s icecap. The red half symbolises the rising and setting sun.

And speaking of the sun: It doesn’t set from 25 May to 25 July. Good for people with low vitamin D.

Language: The official language is Greenlandic. Children learn Greenlandic at school as well as Danish and English. West Greenlandic is the official language but there are dialects spoken in Eastern and Northern Greenland.