. 24/7 Space News .
As different as day and night
by Tarini Konchady for AAS News
Washington DC (SPX) Apr 16, 2021

stock illustration only

Telescopes are getting better and better at detecting the components of exoplanet atmospheres. But what can those components tell us about a planet's climate? It turns out that water vapor may be especially useful in this regard.

As we find more and more exoplanets, we're realizing that our solar system may be the exception to the rule! The menagerie of exoplanets we've discovered so far includes Jupiter-sized planets that are close to their suns, planets with two suns, and planets that take one orbit about their sun to complete one rotation on their axis - these planets are said to be tidally locked.

Just like our tidally locked Moon always shows the same face to the Earth, tidally locked planets always show the same face to their sun. So, a tidally locked planet will have a consistent dayside and nightside. This has fascinating implications for their climate, and even moreso when we consider that there could be tidally locked Earth-like planets!

Models of the water vapor runaway greenhouse effect - when radiation is prevented from efficiently leaving a planet - on tidally locked planets show that the nightside emits more thermal radiation than the dayside as the planet approaches the runaway greenhouse state. Since this reversal of thermal emission requires the emergence of clouds and the buildup of water vapor on the nightside of the planet, spotting it in an exoplanet's atmosphere could be a useful indicator that the atmosphere is not dry.

To achieve nightside buildup of water vapor, the vapor must avoid being caught on the dayside in a "cold trap", where it would be cooled, condense, and remain on the dayside. On a planet with inefficient cold trapping, the water vapor can be swept to the nightside to contribute to the thermal emission there.

This weak cold trap effect has mostly been modeled for planets with warm, thick atmospheres, but it is feasible for this effect to also occur on planets with thin, temperate atmospheres. A recent study done by Feng Ding (Harvard University) and Raymond Pierrehumbert (University of Oxford, UK) explores the second scenario for slowly rotating tidally locked planets.

Simulating Two Sides of a Planet
Ding and Pierrehumbert specifically looked at atmospheres rich in water vapor, which would allow for the necessary clouds and weak cold trap to exist. Their model planet had a period of 40 days and accounted for a variety of interactions that could occur on an Earth-like planet with an atmosphere and oceans. They were also able to vary atmospheric pressure and surface temperature and so modeled several different conditions for their planet.

It turns out that thin, temperate atmospheres with weak cold traps do show the same nightside-dayside emission difference as warm, thick atmospheres as they approach the runaway greenhouse state! Interestingly, the difference between the nightside and dayside emissions can point to the relative amount of water vapor in a planet's atmosphere as well as the atmospheric pressure - insight we can't gain from the planet's transmission spectrum. Further properties of a planet's atmosphere can be determined by observing how the brightness of the planet changes as it rotates.

The subtleties from this study can't be picked up by our telescopes yet, but possible future missions like the Origins Space Telescope may be able to. There's no need to rush though: there are still lots more planets to simulate!

Research Report: "The Phase-curve Signature of Condensible Water-rich Atmospheres on Slowly Rotating Tidally Locked Exoplanets"

Related Links
AAS Nova News
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

Amounts of organic molecules in planetary systems differ from early on
Tokyo, Japan (SPX) Apr 11, 2021
An international group of scientists led by the RIKEN Cluster for Pioneering Research have studied the chemical composition of 50 protoplanetary-disk forming regions in the Perseus Molecular Cloud, and found that despite being in the same cloud, the amounts of complex organic molecules they contain are quite different. Interestingly, the chemically rich young disks have similar compositions of organic molecules. These findings raise an important question: do solar-like systems share a common chemistry a ... 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

Biden proposes 6.3% boost for NASA in budget proposal

Liftoff! Pioneers of space

Astronauts need a fridge

All aboard! Next stop space...

DLR is creating the rocket fuels of the future

Phantom Space raises $5M in seed funding to for space transportation concept

Blue Origin launches what may be final test flight before carrying people

NASA chooses SpaceX to take humans back to Moon

Work progresses toward Ingenuity's First Flight on Mars

NASA delays Mars helicopter flight again for software update

CO2 mitigation on Earth and magnesium civilization on Mars

NASA delays Mars copter flight for tech check

Chinese rocket for space station mission arrives at launch site

Ningbo to build $3.05b rocket launchpad site

China advances space cooperation in 2020: blue book

China selects astronauts for space station program

India's telecom regulator assessing Starlink system before accepting beta

UK space firm In-Space Missions Limited Announces Major Expansion And Job Creation Plans

China to develop aerospace as strategic emerging industry

US space employment, investments resist pandemic in 2020, continue to climb in 2021

Sotheby's sees $16.8 million in first NFT sale

Google unveils $2bn data hub in Poland

Northrop Grumman and Intelsat make history with docking of 2nd Mission Extension Vehicle

New laser to help clear the sky of space debris

Study warns of 'oxygen false positives' in search for signs of life on other planets

Crustal mineralogy drives microbe diversity beneath Earth's surface

Amounts of organic molecules in planetary systems differ from early on

Long-awaited review reveals journey of water from interstellar clouds to habitable worlds

New research reveals secret to Jupiter's curious aurora activity

NASA's Europa Clipper builds hardware, moves toward assembly

First X-rays from Uranus Discovered

SwRI scientists discover a new auroral feature on Jupiter

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.