. 24/7 Space News .
A terrestrial-mass planet on the run?
by Susanna Kohler for AAS Nova
Washington DC (SPX) Nov 22, 2020

illustration only

Scientists have long believed that there may be billions to trillions of rogue planets drifting through our galaxy, unattached to any host star. A recent study has now identified one such candidate - potentially the first terrestrial-mass world we've spotted on the run.

We've discovered more than 4,000 exoplanets in the last three decades, spanning a dramatic range of masses, sizes, temperatures, compositions, orbital properties, and more. The vast majority of them, however, share one feature: they all orbit a star.

While this may seem like normal behavior - after all, we're rather attached to our own star, here on Earth - planetary formation models predict that there should be a large population of free-floating planets in our galaxy. According to the models, these typically sub-Earth-mass planets get kicked out from their parent systems through interactions with other bodies (usually bullying gas giants).

How can we observationally confirm this picture? Without the beacon of a host star's light, free-floating planets are challenging to detect - but they're discoverable via a method called gravitational microlensing.

The Lens Is the Thing
When light from a background source passes by a massive body on its way to us, the intervening object acts as a gravitational lens, bending the light.

In the case of microlensing, the intervening lens object is small - a stellar- or planetary-mass object - so the lensing doesn't produce a resolvable ring of light like in strong lensing. Instead, we see a brief brightening of the background source as the lens passes in front of it. From the shape of the light curve, we can then infer lens and source properties.

Roughly 100 planets have been discovered in microlensing events so far - but in most of these cases, the lensing mass is actually a combination of a planet and its host star. Only a handful of objects have been found so far that might be free-floating planets, and they've all been of relatively large mass.

That is, until now.

Short Blip, Small Planet
A recent study led by Przemek Mroz (California Institute of Technology) presents a new discovery gleaned from data from two gravitational lensing telescopes: the shortest-timescale microlensing event seen yet, OGLE-2016-BLG-1928.

The event was located in high-cadence survey fields, so though the brightening timescale was just 41.5 minutes, the Optical Gravitational Lensing Experiment (OGLE) and the Korea Microlensing Telescope Network (KMTN) managed to capture a joint total of 15 magnified data points. By modeling the light curve, the authors establish that OGLE-2016-BLG-1928 is either a free-floating planet, or its host is located at least 8 au away from it.

Assuming that the planet is located in the galactic disk (which the authors deem likely based on their data), it's estimated to weigh ~0.3 Earth mass, or roughly 3 times the mass of Mars.

So how do our prospects look for finding more of these free-floating low-mass planets and verifying the expectation that they're plentiful? Certainly, this OGLE detection proves it's possible - and with the power of upcoming observatories like the Nancy Grace Roman Space Telescope, odds are good that we'll be able to spot more of these drifting terrestrial worlds.

Research Report: "A Terrestrial-mass Rogue Planet Candidate Detected in the Shortest-timescale Microlensing Event,"

Related Links
AAS Nova
Lands Beyond Beyond - extra solar planets - news and science
Life Beyond Earth

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only
SpaceDaily Contributor
$5 Billed Once

credit card or paypal

Ariel moves from blueprint to reality
Paris (ESA) Nov 16, 2020
ESA's exoplanet mission Ariel, scheduled for launch in 2029, has moved from study to implementation phase, following which an industrial contractor will be selected to build the spacecraft. Ariel, the Atmospheric remote-sensing infrared exoplanet large-survey mission, addresses one of the key themes of ESA's Cosmic Vision programme: What are the conditions for planet formation and the emergence of life? Ariel will study what exoplanets are made of, how they formed and how they evolve, by surveying ... read more

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Marshall team enables increased science return from International Space Station astronauts

A new doorway to space

ISS crew successfully patched hull crack Roscosmos confirms

Resolving mysteries about the first stellar parallaxes and distances

Skyrora conducts vacuum chamber engine tests to replicate space-like conditions

NASA and SpaceX "Go" for Dec. 5 Cargo Resupply Launch

NASA's 'super cool' engineers rehearse rocket fueling for Artemis I

Relativity Space closes $500M Series D financing for 3D rockets

Hear audio from Perseverance as it travels through deep space

Field geology at Mars' equator points to ancient megaflood

ExoMars parachute testing moves forward

Ancient zircon minerals from Mars reveal the elusive internal structure of the red planet

China's space tracking ship sails for Chang'e 5 mission

China Focus: 18 reserve astronauts selected for China's manned space program

State-owned space giant prepares for giant step in space

China's Xichang launch center to carry out 10 missions by end of March

Major funding package pledged for UK Space Centre of Excellence in Ayrshire, Scotland

UK government secures satellite network OneWeb

Ten satellites to be built in Glasgow in next three years

SpaceX's Starlink satellites are about to ruin stargazing for everyone

The "Workspace Of The Future," Carnegie's VizLab Will Unlock The Secrets Of The Universe

Astroscale announces March 2021 Launch Date for Debris Removal Demonstration

China launches antenna array for Mars, moon missions

MDA receives commercial contracts for on-orbit servicing technologies

Here's Looking at You, MKID

New Interdisciplinary Consortium for Astrobiology Research

Building blocks of life can form long before stars

Life's building blocks can form in interstellar clouds without stellar fusion

Swedish space instrument participates in the search for life around Jupiter

Researchers model source of eruption on Jupiter's moon Europa

Radiation Does a Bright Number on Jupiter's Moon

New plans afoot beyond Pluto

The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.