Many Worlds

Tag: Planet 9

Asteroid Remains Around Dead Stars Reveal the Likely Fate of Our Solar System

June 28, 2018 / / 0 Comments

Artist concept of an asteroid breaking up. (NASA/JPL-Caltech)

June 30th has been designated “Asteroid Day” to promote awareness of these small members of our solar system. But while asteroids are often discussed in the context of the risk they might pose to the Earth, their chewed up remains around other stars may also reveal the fate of our solar system.

It is 6.5 billion years into our future. The sun has fused hydrogen into a core of heavier helium. Compressed by its own gravity, the helium core releases heat and the sun begins to swell. It is the end of our star’s life, but what will happen to the solar system?

While very massive stars end their element-fusing days in a colossal explosion known as a supernovae, the majority of stars in our galaxy will take a less dramatic exit.

Our sun’s helium core will fuse to form carbon but there is not enough mass to achieve the crushing compression needed for the creation of heavier elements. Instead, the outer layers of the dying star will be blown away to leave a dense remnant with half the mass of our current sun, but squeezed down to the size of the Earth. This is a white dwarf; the most common of all stellar ends.

The life cycle of our sun

The white dwarf rapidly cools to become a dim twinkle in the sky. Within a few million years, our white dwarf will be less luminous that the sun today. Within 100 million years, it will be dimmer by a factor of 100. But examination of white dwarfs in our galaxy reveals this gentle dimming of the lights is not as peaceful as first appears.

The remnants of stars too light to fuse carbon, white dwarfs have atmospheres that should be thin shells of residue hydrogen and helium. Instead, observations have detected 20 different heavy elements in this envelope of gases that include rock-forming elements such as silicon and iron and volatiles such as carbon and nitrogen.

Infrared observations of over forty white dwarfs have additionally revealed compact dusty discs circling the dead stars. Sitting within the radius of a regular star, these could not have formed before the star shrank into a white dwarf. These must be the remains of what occurred as the star morphed from a regular fusion burner into a white dwarf.

This grizzly tale begins with the star’s expansion.… Read more

The Case Strengthens For "Planet 9"

September 1, 2016 / / 0 Comments
Caption: An artist’s conception of Planet X, courtesy of Robin Dienel.

An artist’s conception of Planet 9, or Planet X, which scientists theorize orbits in the distant solar system.  (Robin Dienel/ Carnegie Institution of Washington)

The race is on to find the giant planet that several teams of astronomers are convinced orbits far out beyond Pluto, but is nonetheless still part of our solar system.  Proving the existence of what has become known as Planet X, or Planet 9, would be a discovery for the textbooks and would inevitably change our understanding of how our solar system was formed.

The technology and luck needed to image the planet (if it truly is there) has thus far fallen short, but the discovery of another set of distant solar system objects traveling in surprising orbits has added to the indirect findings that point to a substantial, and perhaps giant planet in the general vicinity.

The new findings come from Scott Sheppard of the Carnegie Institution for Science and Chadwick Trujillo of Northern Arizona University, who two years ago provided some of the first intriguing inklings that this distant planet might exist in our solar system.  That information was subsequently modified and broadened by a California Institute of Technology team, but with the same conclusion that a substantial Planet 9 appeared to be present in the outer solar system.

“What we’ve just released is data on the first extreme objects since the {2014 and 2016} reports of a theorized Planet 9,  and they show the same clustering and orbiting patterns that we think are likely caused by a major planet,” Sheppard said.

“This continues the trend of finding these objects — small dwarf planets or maybe icy objects — that were pushed into similar orbits in ways we think only planets can do.”

“We need more,” he said, “but the evidence is mounting, and at this point I’d say there’s an 80 percent likelihood that the planet is there.”

An illustration of the orbits of 2013 FT28, 2014 SR349, and previously known extremely distant Solar System objects. The clustering of most of their orbits indicates that they are likely be influenced by something massive and very distant, the proposed Planet Nine. Image credit: Robin Dienel.

An illustration of the orbits of newly-discovered small, trans-Neptune objects 2013 FT28, 2014 SR349, and previously known extremely distant Solar System objects. The clustering of most of their orbits indicates that they are likely be influenced by something massive and very distant, the proposed Planet 9 . (Carnegie Institution of Washington, Robin Dienel)

Some call the potential celestial object Planet X and some call it Planet 9 — as in, the ninth planet in our solar system now that Pluto has been demoted to a dwarf planet. … Read more

How Planet 9 Would Make Ours a More Typical Solar System

February 4, 2016 / / 0 Comments

 

The six most distant known objects in the solar system with orbits exclusively beyond Neptune (magenta) all mysteriously line up in a single direction. The new report shows a planet with 10 times the mass of the earth in a distant eccentric orbit anti-aligned with the other six objects (orange) is required to maintain this configuration. Image: Caltech/R. Hurt (IPAC)"

The six most distant known objects in our solar system with orbits (magenta) exclusively beyond Neptune all mysteriously line up in a single direction. A new report identifies the potential presence of a distant solar system planet — with 10 times the mass of the Earth and in a distant and eccentric orbit (orange) — as the reason why.  (JPL/Caltech; R. Hurt)

There’s been a ton of justifiable excitement these days about the possible discovery of a ninth planet in our solar system — an object ten time the mass  of Earth and 200 times further from the sun.  Especially in the context of the recent demotion of Pluto from a planet to a dwarf planet, the announcement of a potential replacement seems almost karmic, stage managed, in its take-and-give.  This is especially so since the astronomer probably most responsible for the diminished position of Pluto is also the one who now asserts the very far away presence of a different Planet 9 — planetary astronomer Michael Brown of the California Institute of Technology.

The validity of the possible detection of a Planet 9 has set off hot debates — with NASA officials, for instance, making clear that the agency sees the “discovery” as an exciting but early step towards establishing the existence of possible new planet.  We are all drawn to discovery and controversy, so the presence, or non-presence, of the planet has been the focus of attention.

But another most intriguing aspect of the finding has been largely ignored — the way  that such a Planet 9 would make our solar system surprisingly more similar to the many more eccentric exoplanet solar systems now known to be out there.  Our solar system would also suddenly have a range of planets sized more like the galactic norm.

What’s more, there’s reason to consider that a Planet 9 could have been spun off another solar system rather than having been ejected from the inner solar system, as proposed by Brown and colleague Konstantin Batygin.

In other words, Planet 9 may be an “exoplanet” in origin.  And if not, a finding that it was ejected long ago from our inner solar system would answer some questions about why our system seems to be so different from many of the other exoplanetary systems discovered so far.

Mike Brown and Konstanytin Batyglin of Caltech

Astronomers Mike Brown and Konstantin Batygin of Caltech.  They took research by Scott Shepard of the Carnegie Institution for  Science and Chad Trujillo of the Gemini Observatory in Hawaii regarding the unusual paths of objects orbiting beyond Pluto and carried it further to conclude there is a Planet 9 in the distant solar neighborhood. 

… Read more

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