Rogue Planets (Solo / Orphan Planets Without Suns)

[Jerry_B]

Solar System Likely Once Had Another Gas-Giant Planet

To evolve into our current solar system, the original version probably had a fifth gas giant, computer simulations indicate.

Jupiter, Saturn, Uranus and Neptune. Those are the gas giants, the four heavyweights of the solar system. But was there once a fifth?

Maybe so, says a new study by David Nesvorny of the Southwest Research Institute in Boulder, Colorado. He used computer simulations to explore what the solar system may have looked like some four billion years ago.

Early on, the giant planets migrated, tugged on each other and generally shook things up before settling into their current orbits. So the simulation tested different initial arrangements of planets to see which would evolve into the solar system we know so well.

With just four giant planets at the outset, the solar system hardly ever wound up looking like ours. But with a fifth planet, the simulations produced familiar solar systems 10 times more often. [David Nesvorny, "Young Solar System's Fifth Giant Planet?" on arXiv.org]

So what happened to the extra planet? It would have run afoul of Jupiter and been chucked into interstellar space. Astronomers have recently discovered that the galaxy is filled with such orphaned planets. Billions of them. So, if an extra planet did get cast out of the solar system, at least it has plenty of company.

Source (with podcast)

 

[GNC]

Would this gas giant cast adrift have had any moons? And would the moons have stuck with it on its journey into deep space?

 

[rynner2]

Would this gas giant cast adrift have had any moons? And would the moons have stuck with it on its journey into deep space?

I expect some of them would, but the more distant moons might have got lost or (more probably) were captured by Jupiter itself, if Jupiter was the disrupter.

 

[eburacum]

Note that a gas giant in deep space might not be all that different to one in orbit around a star. Although the top of the planet's atmosphere would be very cold, a planet resembling Jupiter would have an independent source of heat within, as the vast mass of the planet slowly contracts over time and liberates potential energy into heat. Such heat of contraction would warm the planet for billions of years.

If such a rogue world retained a family of moons they might interact with each other through tidal effects, enough to heat some such worlds internally. A deep space Io or Europa would be almost as warm out there as on the fringes of our solar system. You could even get life, assuming abiogenesis could occur. Imagine a civilisation on an icy moon of a rogue gas giant, far from any star - they might never realise that the distant points of light in their skies are also accompanied by planets.

 

[rynner2]

Imagine a civilisation on an icy moon of a rogue gas giant, far from any star - they might never realise that the distant points of light in their skies are also accompanied by planets.

Without a 'sun', though, they may never evolve sight in the first place, unless their atmosphere is clear enough to show the stars. In that case there might be some evolutionary advantage to having sight. Otherwise they might be something like the blind creatures that live in deep dark caves on Earth.

 

[GNC]

Very interesting, thanks guys. I'll be honest, though: I was thinking Space 1999!

 

[ramonmercado]

First possible exomoon spotted
Worlds around other worlds may be habitable.

Alexandra Witze
23 December 2013

NASA/JPL-Caltech

Many exoplanets may have moons orbiting them.

Even as the number of planets known beyond the Solar System climbs above 1,000, the discovery of an accompanying exomoon has remained elusive — until, perhaps, now.

Many exoplanets probably have moons orbiting them. Some of those moons might even be large enough, and have an atmosphere, to host extraterrestrial life.

On a June night two years ago, a telescope in New Zealand captured a momentary brightening of a star in the constellation Sagittarius. It was an occurence of a rare phenomenon known as microlensing, in which a star or planet or other celestial object passes directly between Earth and a more distant star, gravitationally magnifying the light of the faraway star.

After sifting through detailed observations of this event, astronomers proposed that the intervening object could be either a smallish star with a Neptune-sized planet orbiting it, or a largish planet with a moon orbiting it.

If the latter possibility is confirmed, it would be the first ever detection of an exomoon. The problem is that there is no way to repeat the observation and know for sure.

“It’s kind of a shame because we’ll probably never know what the answer is,” says David Kipping, an astronomer at the Harvard?Smithsonian Center for Astrophysics in Cambridge, Massachusetts, who was not involved in the research.

The possible discovery was reported in a paper posted on 13 December on the arXiv preprint server1. It comes from a group of scientists studying microlensing that is led by David Bennett, an astrophysicist at the University of Notre Dame in Indiana. He declined to speak about the work until it is published in a peer-reviewed journal.

Star light, star bright
Once the telescope in New Zealand spotted the brightening, other telescopes in the Southern Hemisphere, as well as one of the Keck telescopes in Hawaii, were turned to watch it. From measurements taken by these telescopes of how the star’s brightness changed over time, Bennett’s team deduced the type of object that had passed through the telescopes' field of view.

The star's light didn't brighten in a single sharp peak, but smeared out as if two objects had magnified the light. From the data the scientists calculated the most likely possibilities for what the masses of what these two objects would be — which depends on the unknown parameter of how nearby they are. If they are relatively close to Earth, then they could be a relatively lightweight planet and its moon. If they are more distant, they could be a heavier star with a planet.

Either way, the pair of objects is roaming deep space on their own, an observation that raises questions about how an exoplanet and its exomoon could get that way. At least one earlier microlensing study has hinted that there could be billions of rogue planets wandering the cosmos, unbound to any star. But they are likely to have been kicked out of their stellar systems through violent gravitational interactions, and in the process lost any accompanying moons. “An apparently free-floating planet with a half Earth-mass moon would be a new class of system that was not previously known to exist,” Bennett and his team write. “Such a new discovery would require strong evidence, so our favored model for this event is that it is a low-mass star or brown dwarf orbited by a planet of about Neptune’s mass.”

That pessimistic conclusion does not deter Kipping. He leads a project hunting for exomoons using data from NASA’s planet-finding Kepler spacecraft, which monitors the sky looking for regular dips in light when a planet crosses in front of a star. Of the more than 3,500 candidate exoplanets that Kepler has found, about 300 of them have orbital characteristics that make them capable of holding onto a moon, Kipping says. Of those, at least 150 show hints in the data that could be explained by the presence of an exomoon.

One by one, his team is crunching through detailed studies to either confirm or rule out each possible exomoon. “The beauty of what we have is that we can see events over and over again, whereas microlensing has one snapshot,” says Kipping.

On many of those later passes, tantalizing hints of exomoons disappear. He still has a lot of data to work through, though. ”We've barely scratched the surface,” he says.

http://www.nature.com/news/first-possib ... ed-1.14430
Nature doi:10.1038/nature.2013.14430

References

Bennett, D. P. et al. Preprint available at http://arxiv.org/abs/1312.3951 (2013).

 

[EnolaGaia]

A new telescope has the potential to blow our minds with discovery of more rogue planets than we currently suspect to exist ...

Space Could Be Filled With Hidden 'Rogue' Planets - And We May Soon Be Able to See Them

Hidden among the seeming endlessness of space, there could be countless worlds that never see the light of day. These mysterious bodies, called rogue planets, are not like other planets, although there could be multitudes of them.

In our own Solar System, Earth and all its planetary siblings orbit around the Sun, bathing in its warmth and light. Rogue planets, on the other hand, are unbound to any star – they simply drift alone through empty space, belonging to nothing except the darkness.

They stray so far from starlight, in fact, they're very difficult to see at all.

"The Universe could be teeming with rogue planets and we wouldn't even know it," says astronomer Scott Gaudi from Ohio State University (OSU).

These rogues won't be able to hide from us for much longer, though.

Sometime in the next few years, NASA will be launching the Nancy Grace Roman Space Telescope – a new US$4 billion space observatory, with optics expected to give us a field of view 100 times greater than the famous Hubble Telescope. ...

"This gives us a window into these worlds that we would otherwise not have," Johnson says.

"There have been several rogue planets discovered, but to actually get a complete picture, our best bet is something like Roman. This is a totally new frontier."

While there's much we don't yet understand about how rogue planets come to be, it's thought they may form in gaseous disks around stars, before being flung from their star systems through gravitational forces.

Alternatively, they might take shape in a manner similar to how stars form, being born when a cloud of gas and dust collapse – only it produces an isolated, low-mass planet, instead of a stellar core.

The origin mechanisms remain mysterious, for now, but what's clearer is how the Roman telescope will be able to perceive these entities drifting through the dark: a technique called gravitational microlensing. ...

As for what the expected detections of rogue planets will reveal about the greater cosmos, nobody yet knows for sure – but it could turn out that gravitationally bound planets, clinging onto stars, are not the universal standard we assumed they were. ...

FULL STORY: https://www.sciencealert.com/there-...in-space-than-we-ever-realised-scientists-say

 

[EnolaGaia]

Ongoing research using microlensing techniques has identified rogue planets within our Milky Way galaxy.

Astronomers Say They've Detected a Rogue Earth-Mass Planet Drifting in The Milky Way

If a solar system is a family, then some planets leave home early. Whether they want to or not. Once they've left the gravitational embrace of their family, they're pretty much destined to drift through interstellar space forever, unbound to any star.

Astronomers like to call these drifters "rogue planets," and they're getting better at finding them. A team of astronomers have found one of these drifting rogues that's about the same mass as Mars or Earth.

Finding something in deep space that emits no light of its own is extremely challenging. But two organizations are doing just that. They're the OGLE (Optical Gravitational Lensing Experiment) collaboration and the KMTN (Korean Microlensing Telescope Network) collaboration.

Now, a team of scientists from both groups have announced the discovery of a low-mass rogue planet. There are no stars near it, and its distance from Earth is unconfirmed. ...

Theoretical work shows that there could be billions, or even trillions, of free-floating planets in the Milky Way. ...

FULL STORY:
https://www.sciencealert.com/rogue-...th-found-drifting-through-the-dark-on-its-own

PUBLISHED RESEARCH REPORT:
(Pre-press phase)
A terrestrial-mass rogue planet candidate detected in the shortest-timescale microlensing event
https://arxiv.org/pdf/2009.12377.pdf

 

[Trevp666]

Interesting addition to the little we already know about this phenomena.

Kepler telescope glimpses population of free-floating planets

https://phys.org/news/2021-07-kepler-telescope-glimpses-population-free-floating.html

 

[EnolaGaia]

Newly published research reports the discovery of at least 70 new rogue planets within our Milky Way and clues that the number of such rogue planets is much greater than previously suspected.

Mysterious Galactic Nomads: At Least 70 Rogue Planets Uncovered in Our Milky Way

Rogue planets are elusive cosmic objects that have masses comparable to those of the planets in our Solar System but do not orbit a star, instead roaming freely on their own. Not many were known until now, but a team of astronomers, using data from several European Southern Observatory (ESO) telescopes and other facilities, have just discovered at least 70 new rogue planets in our galaxy. This is the largest group of rogue planets ever discovered, an important step towards understanding the origins and features of these mysterious galactic nomads. ...

“We did not know how many to expect and are excited to have found so many,” says Núria Miret-Roig, an astronomer at the Laboratoire d’Astrophysique de Bordeaux, France and the University of Vienna, Austria, and the first author of the new study published today (December 22, 2021) in Nature Astronomy.

Rogue planets, lurking far away from any star illuminating them, would normally be impossible to image. However, Miret-Roig and her team took advantage of the fact that, in the few million years after their formation, these planets are still hot enough to glow, making them directly detectable by sensitive cameras on large telescopes. They found at least 70 new rogue planets with masses comparable to Jupiter’s in a star-forming region close to our Sun, located within the Scorpius and Ophiuchus constellations. ...

The team used observations from ESO’s Very Large Telescope (VLT), the Visible and Infrared Survey Telescope for Astronomy (VISTA), the VLT Survey Telescope (VST) and the MPG/ESO 2.2-meter telescope located in Chile, along with other facilities. ...

The study suggests there could be many more of these elusive, starless planets that we have yet to discover. “There could be several billions of these free-floating giant planets roaming freely in the Milky Way without a host star” ...

By studying the newly found rogue planets, astronomers may find clues to how these mysterious objects form. Some scientists believe rogue planets can form from the collapse of a gas cloud that is too small to lead to the formation of a star, or that they could have been kicked out from their parent system. But which mechanism is more likely remains unknown. ...

FULL STORY: https://scitechdaily.com/mysterious...-70-rogue-planets-uncovered-in-our-milky-way/

PUBLISHED REPORT:
Miret-Roig, N., Bouy, H., Raymond, S.N. et al.
A rich population of free-floating planets in the Upper Scorpius young stellar association.
Nat Astron (2021).
https://doi.org/10.1038/s41550-021-01513-x

 

[Timble2]

Bronson Alpha and Bronson Beta

 

[eburacum]

Here's a fictional rogue planet I worldbuilt a few years ago; Hyxuym
https://orionsarm.com/eg-article/56a687306fd47