STScI: Pair of Fledgling Planets Seen Growing around Young Star

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STScI: Pair of Fledgling Planets Seen Growing around Young Star

Post by bystander » Mon Jun 03, 2019 5:15 pm

Pair of Fledgling Planets Seen Growing around Young Star
NASA | STScI | HubbleSite | 2019 Jun 03
Astronomers have directly imaged two exoplanets that are gravitationally carving out a wide gap within a planet-forming disk surrounding a young star. While over a dozen exoplanets have been directly imaged, this is only the second multi-planet system to be photographed. (The first was a four-planet system orbiting the star HR 8799.) Unlike HR 8799, though, the planets in this system are still growing by accreting material from the disk. ...

The host star, known as PDS 70, is located about 370 light-years from Earth. The young 6-million-year-old star is slightly smaller and less massive than our Sun, and is still accreting gas. It is surrounded by a disk of gas and dust that has a large gap extending from about 1.9 to 3.8 billion miles.

PDS 70 b, the innermost known planet, is located within the disk gap at a distance of about 2 billion miles from its star, similar to the orbit of Uranus in our solar system. The team estimates that it weighs anywhere from 4 to 17 times as much as Jupiter. It was first detected in 2018.

PDS 70 c, the newly discovered planet, is located near the outer edge of the disk gap at about 3.3 billion miles from the star, similar to Neptune’s distance from our Sun. It is less massive than planet b, weighing between 1 and 10 times as much as Jupiter. The two planetary orbits are near a 2-to-1 resonance, meaning that the inner planet circles the star twice in the time it takes the outer planet to go around once.

The discovery of these two worlds is significant because it provides direct evidence that forming planets can sweep enough material out of a protoplanetary disk to create an observable gap. ...

Two Accreting Protoplanets around the Young Star PDS 70 ~ S.Y. Haffert et al
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Monash: Physicists Discover New Clue to Planet Formation

Post by bystander » Wed Jun 05, 2019 2:11 pm

Monash Physicists Discover New Clue to Planet Formation
Monash University | 2019 Jun 03
An international study led by the Monash School of Physics and Astronomy has discovered the first observational evidence for the existence of circumplanetary discs.

The study published in the Astrophysical Journal Letters focused on young planets still in the process of formation (typically only a few million years old).

“Our research helps us to understand how our 4.6 billion year-old Solar System came about, and how we got here,” said lead study author Dr Valentin Christiaens, a Postdoctoral Research Fellow in Astrophysics at Monash University.

The research team used the Very Large Telescope facility in Chile to obtain infrared images in different colours (wavelengths) of a newborn giant planet.

“We found the first evidence for a disc of gas and dust around it - known as a circumplanetary disc,” said Dr Christiaens.

“We think the large moons of Jupiter and other gas giants were born in such a disc, so our work helps to explain how planets in our Solar System formed,” he said.

Seeing the moons of Jupiter through a telescope had Galileo arrested in his day, because he saw that not everything orbited the Earth, and we were therefore not the centre of the Universe. ...

Evidence for a Circumplanetary Disk around Protoplanet PDS 70 b ~ Valentin Christiaens et al
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor