mare

Borrowed from Latin mare (“sea”). Doublet of mar and mere.

(planetology) A large, dark plain, which may have the appearance of a sea, such as those on the Moon

Kraken Mare (a lake of liquid hydrocarbons on Titan which is slightly larger than the Caspian Sea)

(planetology) On Saturn's moon Titan, any of several lakes which are large expanses of what is thought to be liquid hydrocarbons.


sea

Inherited from Middle English see, from Old English sǣ, from Proto-West Germanic *saiwi (“body of water”), from Proto-Germanic *saiwiz, itself either:
* Derived from Proto-Indo-European *sh₂ey-wo- (“to be fierce, afflict”). Related to Latin saevus (“wild, fierce”), Tocharian B saiwe (“itch”), and Latvian sievs, sīvs (“sharp, biting”). More at sore.
* Derived from Proto-Germanic *sīhwaną (“to percolate, filter”), from Proto-Indo-European *seykʷ-.
Cognate with Danish sø, Dutch zee, German See, Norwegian Bokmål sjø, Swedish sjö, and West Frisian see.

der+

The Apollo 11 mission landed in the Sea of Tranquility.

(planetology) A large, dark plain of rock; a mare.

(planetology) A very large lake of liquid hydrocarbon.


palus

(planetology) A small plain (compared to mare) on the surface of a planet or satellite.


geyser

desc

→ Bengali: গিজার (gijar, “water boiler”)

→ Hindi: गीज़र (gīzar, “water heater”)

From the name of a particular Icelandic geyser which is mentioned as early as the 1760s in The Annual Register, as “Geyser, a wonderful spring in the valley of Haukadal”. From Geysir (“Gusher”), the Icelandic name of the hot spring in Iceland (see Wikipedia), from the verb geysa (“to gush”), from Old Norse geysa (“to gush”). Doublet of gusher.

(planetology, geology, volcanology) A boiling natural spring which throws forth jets of water, mud, etc., at frequent intervals, driven upwards by the expansive power of steam.

fons calidae atque alte exsilientis aquae


rill

From or akin to West Frisian ril (“rill; a narrow channel”), Dutch ril (“rill; gully; trench; watercourse”), German Low German Rille, Rill (“a small channel; brook; furrow”), German Rille (“a groove; furrow”).

cog

(planetology) Alternative form of rille.


tessera

Borrowed from Latin tessera (“a cube, a die with numbers on all six sides”), from Ancient Greek τέσσαρες (téssares, “four”).

uder

(planetology) complex-ridged surface feature seen on plateau highlands of Venus and perhaps on Triton


chasm

General American, uncommon, spelling pronunciation

From Latin chasma, from Ancient Greek χάσμα (khásma, “abyss, cleft”).

chasma

long, narrow, steep-sided depression on a body in the solar system

But always and ever there is a yawning chasm below[.]

2019, Li Huang, James Lambert, “Another Arrow for the Quiver: A New Methodology for Multilingual Researchers”, in Journal of Multilingual and Multicultural Development, →DOI, page 1:

(geology, planetology) A deep, steep-sided rift, gap or fissure; a gorge or abyss.


DPS

Division for Planetary Sciences
w:Division for Planetary Sciences

(US, planetology) Initialism of Division for Planetary Sciences.


SLE

(planetology, areology) Initialism of single-layer ejecta.


Mohorovičić discontinuity

/məʊhəʊˈɹə(ʊ)vɪtʃɪtʃ ˌdɪskɒntɪˈnjuːɪti/

Andrija Mohorovičić
Mohorovicic discontinuity

Named for Croatian seismologist Andrija Mohorovičić (1857-1936).

(astrogeology, planetology) A similar structure on other bodies, that separates crust from mantle.


QCD

Quasi Circular Depression
w:Quasi Circular Depression

(planetology) Initialism of Quasi Circular Depression.


Ionian

en-adj

Ionian (comparative more Ionian, superlative most Ionian)

more Ionian (comparative)
most Ionian (superlative)

* (Hellenic, Ionia, architecture): Ionia + -n
* (moon of Jupiter): Io + -n- + -ian

Bagenal, Dowling & McKinnon (2007), Jupiter: The Planet, Satellites and Magnetosphere. Cambridge University Press, p. 313.
Despite the variations in Ionian vulcanism ...

(astronomy, planetology) Relating to Io, one of the moons of the planet Jupiter.


hot spot

hot spots (plural)
hotspot (alternative)

пизэке

place notable for a high level of activity or danger

While researchers can see the path that Yellowstone burned as the hot spot migrated from Oregon across Idaho and into Wyoming, discerning one eruption from another has been a chore as most volcanic deposits are scattered across vast landscapes in a chaotic jumble.

2020 June 18, Matt Kaplan, “Yellowstone’s supervolcano is a hot spot, but it may be calming down”, in The New York Times, New York, N.Y.: The New York Times Company, →ISSN, →OCLC, archived from the original on 2021-04-21:

A location which has a higher temperature or amount of radiation than surrounding areas.

(geology, planetology) The surface manifestation of a plume of molten material that rises from deep in a celestial body's mantle.

熱點 /热点

surface manifestation of a plume that rises from deep in a celestial body’s mantle


Osiris

/əʊˈsaɪ.ɹɪs/

/əʉˈsɑɪ.ɹɪs/

/ɐʉˈsaɪ.ɹəs/

Borrowed from Latin Osīris, derived from Ancient Greek Ὄσῑρῐς (Ósīrĭs), derived from Egyptian wsjr.

der+

(astronomy, planetology) An exoplanet in the Pegasus constellation, HD 209458 b.


sulcus

Borrowed from Latin sulcus (“a furrow made by a plow”). Doublet of sullow ("plough").

bor+

(planetology) A region of subparallel grooves or ditches formed by a geological process.


exoplanet

exoplanets (plural)
exo-planet (alternative)

Constructed from Ancient Greek: exo- (“outside; extrasolar”) + planet.

More such announcements will likely come in the months to follow, as the first space observatory dedicated to hunting exoplanets, called COROT, begins full operation and researchers complete their calculations.

2007, Alexander Hellemans, “Dangling a COROT”, in Scientific American, volume 297, number 3, page 32:

In the past two years, NASA’s Kepler Space Telescope has located nearly 3,000 exoplanet candidates ranging from sub-Earth-sized minions to gas giants that dwarf our own Jupiter. Their densities range from that of styrofoam to iron.

2013 May-June, Kevin Heng, “Why Does Nature Form Exoplanets Easily?”, in American Scientist, volume 101, number 3, page 184:

In a first for astronomers studying worlds beyond our solar system, data from the Hubble Space Telescope have revealed water vapor in the atmosphere of an Earth-size planet. Although this exoplanet orbits a star that is smaller than our sun, it falls within what’s known as the star’s habitable zone, the range of orbital distances where it would be warm enough for liquid water to exist on a planet’s surface.

2019 September 11, Michael Greshko, “Water found on a potentially life-friendly alien planet”, in National Geographic:

Now a team of researchers is offering what it contends is the strongest indication yet of extraterrestrial life, not in our solar system but on a massive planet, known as K2-18b, that orbits a star 120 light-years from Earth. A repeated analysis of the exoplanet’s atmosphere suggests an abundance of a molecule that on Earth has only one known source: living organisms such as marine algae.

2025 April 16, Carl Zimmer, “Astronomers Detect a Possible Signature of Life on a Distant Planet”, in The New York Times, →ISSN, →OCLC, archived from the original on 2022-04-16, Science:

(astronomy, planetology) A planet which exists outside Earth's solar system.

كَوْكَب خَارِج اَلْمَجْمُوعَة اَلشَّمْسِيَّة

太陽系外惑星

たいようけいがいわくせい


roaster

From Middle English roster, roostare, equivalent to roast + -er (agent noun suffix) or + -er (patient suffix). Same formation as roster, although the words have very different meanings.

Some of the earliest discoveries of exoplanets were roasters because they are the least difficult to detect.

(planetology, informal) An epistellar gas giant exoplanet.


hot Jupiter

Or, to put it a different way, the chance of finding a hot Jupiter is 100 times higher than the chance of finding a normal Jupiter, because it is 100 times closer to its parent star.

2010, James Kasting, How to Find a Habitable Planet, Princeton, N.J.: Princeton University Press, →ISBN, →LCCN, →OCLC, page 224:

(planetology) An exosolar planet whose characteristics are similar to Jupiter, but which orbits its parent star much more closely and thus has higher temperatures.


rille

(planetology) A long, narrow depression that resembles a channel, found on the surface of various lunar and planetary bodies.


radargram

/ˈɹeɪdɑɹɡɹæm/

(planetology, geology) A radar image of mineral deposits or a planetary surface.


superchondritic

LL-Q1860 (eng)-Flame, not lame-superchondritic.wav

(planetology, of an elemental ratio) Greater than found in a typical chondrite.


chondritic

en-adj

chondritic (comparative more chondritic, superlative most chondritic)

more chondritic (comparative)
most chondritic (superlative)

(planetology, of an elemental ratio) Similar to that found in chondrites.


cryovolcano

en-noun

cryovolcano (plural cryovolcanoes or cryovolcanos)

cryovolcanoes (plural)
cryovolcanos (plural)

(planetology, geology, volcanology) A volcano on an icy moon that ejects volatile materials rather than magma.


polar cap

Earth's polar caps may melt if global warming continues.

The southern polar cap of Mars consists of both carbon dioxide and water ice.

(planetology) A high-latitude region of a celestial body that is covered by ice.


albedo feature

(planetology) On a Solar System body, a region with distinct brightness when seen using a telescope; often does not correspond any real geological formation.


superplanet

LL-Q1860 (eng)-Flame, not lame-superplanet.wav

(astronomy, planetology) Any very large planet, but especially a large superjovian gas giant


MLE

MLE (countable and uncountable, plural MLEs)

(planetology, areology) Initialism of multi-layer ejecta.


inner core

(planetology) The solid material found in the centre of some planets at extremely high temperature and pressure, distinct from the liquid outer core.

(geology) The innermost part of the Earth, believed to be made of a nickel-iron alloy.


cryovolcanic

/ˈkɹʌɪəʊvɒlˈkanɪk/

(geology, planetology) of or pertaining to a cryovolcano

kryovulkanisch

changed or affected by the heat of a volcano


DLE

(planetology, areology) Initialism of double-layer ejecta.


outer core

(planetology) The hot liquid material found near the centre of some planets, distinct from the solid inner core.

(geology) The part of the Earth between the mantle and inner core, responsible for generating the planet's magnetic field.


pegasid

Named for one of the earliest-discovered exoplanets, 51 Pegasi b, which was discovered in the constellation Pegasus in 1995.


Peace Vallis

Named on September 26, 2012 by the International Astronomical Union as a valley in the Aeolis quadrangle on the planet Mars Aeolis (“Aeolis quadrangle”).

(planetology) A valley within Gale Crater near the landing site (Bradbury Landing) of the Curiosity rover on the planet Mars.


exocomet

Constructed from Ancient Greek: exo- + comet

(astronomy, planetology) An extrasolar comet; A comet which exists outside Earth's solar system, including interstellar comets and comets that orbit stars other than the sun.


interstellar comet

interstellar comet (plural interstellar comets)

(astronomy, planetology) A comet (or exocomet) located in interstellar space, and not gravitationally bound to a star.


interstellar planet

interstellar planet (plural interstellar planets)

Constructed from Latin: inter- + stellar + planet. The latter derives from Middle English planete, from Old English planēta (“planet, chasuble”), from Latin planeta, planetes, from Ancient Greek πλανήτης (planḗtēs) variant of πλάνης (plánēs, “wanderer, planet”), from πλανάω (planáō, “wander about, stray”), of unknown origin. Perhaps from a Proto-Indo-European *pel- (“to wander, roam”), cognate with Latin pālor (“wander about, stray”), Old Norse flana (“to rush about”), Norwegian flanta (“to wander about”). More at flaunt.

der

(astronomy, planetology) a planetary-mass object which has either been ejected from its system or was never gravitationally bound to any star or other such object, and that therefore orbits the galaxy directly.


subchondritic

According to the model, a magma ocean that differentiated chiefly at low pressure and contained 6-8 wt% A1203 and a subchondritic Ca/Al ratio probably formed the lunar crust.

1979, International Aerospace Abstracts, page 3096:

The subcontinental lithospheric mantle as a mantle reservoir may be modeled by the time-integrated growth of radiogenic ¹⁸⁷Os along retarded (subchondritic) Re/Os trajectories, which results in subchondritic Os isotope compositions.

1999, David Dillon Lambert, Application of radiogenic isotopes to ore deposit research and exploration, page 35:

If all the Ag were delivered prior to the main phase, the core segregation by about 30 Ma when the Earth was 90% accreted, then a subchondritic ¹⁰⁷Ag/¹⁰⁹Ag would be expected because of strong depletion of siderophile element Pd in the silicate Earth.

2016, Hidenori Terasaki, Deep Earth: Physics and Chemistry of the Lower Mantle and Core:

(planetology, of an elemental ratio) Less than that found in a typical chondrite.


epistellar Jovian

en-noun

epistellar Jovian (plural epistellar Jovians)


hot Neptune

(planetology) An exosolar planet whose characteristics are similar to the ice giants Uranus and Neptune, but which orbits its parent star much more closely and thus has higher temperatures.


WEG

(planetology) Abbreviation of Water Equivalent to a Global layer (how high a water level would be at 1 atm pressure, if the whole ice had melted).


RSL

recurrent slope linea
recurrent slope linea#English

(planetology) Initialism of recurrent slope linea.


cryomagma

cryomagma (countable and uncountable, plural cryomagmas)

(planetology, geology, volcanology) Collectively, substances such as water, ammonia or methane that are found within some planets and are expelled by cryovolcanoes.


LPSC

w:Lunar and Planetary Science Conference

(planetology, space science) Initialism of Lunar and Planetary Science Conference.


areoid

From areo- (“Mars”) + -oid (“like”). From Ancient Greek Ἄρης (Árēs, “Ares”), the Greek God of War, equivalent to the Roman God of War Mars (“Mars”), synonymous use for the Red Planet; and Ancient Greek -ειδής (-eidḗs, “-oid”) suffix. Coined in analogy to geoid, the equivalent for planet Earth.

(astronomy, geology, planetology) The analogue of the geoid for the planet Mars; the Martian geoid. The gravitational and rotational equipotential surface for Mars. The surface that provides the datum line (the equivalent for sea level) for Mars.


aphroditoid

From aphrodito- (“Venus”) + -oid (“like”). From Ancient Greek Ἀφροδίτη (Aphrodítē, “Aphrodite”), the Greek Goddess of Love, equivalent to the Roman Goddess of Love Venus (“Venus”), synonymous use for the planet; and Ancient Greek -ειδής (-eidḗs, “-oid”) suffix. Coined in analogy to geoid, the equivalent for planet Earth.

uder

(astronomy, geology, planetology) The analogue of the geoid for the planet Venus; the Venusian geoid. The gravitational and rotational equipotential surface for Venus. The surface that provides the datum line (the equivalent for sea level) for Venus.

aphroid

uses the shorter prefix aphro- instead of the longer aphrodito-


recurrent slope linea

en-noun

recurrent slope linea (plural recurrent slope lineae)

From recurrent + slope + linea. From being a line-like marking found on sloped terrain that has occurred multiple times on the same slope area.

(aerology, aerography, planetology) An ephemeral dark linear feature found on slopes that recurs seasonally.


rogue planet

(planetology) A planet that flies through interstellar space and lacks a star to encircle.


Sea of Storms

Blend of sea + Ocean of Storms. Variation of Ocean of Storms; replacement of the rare "Ocean" with the common "Sea", where many features on the Moon are called 'seas' (the maria), and only this one feature is called 'ocean'.

Mare Procellarum
Mare Procellarum#Translingual

Oceanus Procellarum
Oceanus Procellarum#Translingual

(planetology) Mare Procellarum: Synonym of Ocean of Storms (“Oceanus Procellarum”); A basin in Nearside, Moon, Earth, Solar System


Ocean of Storms

Calque of Latin Oceanus Procellarum (literally “Ocean of Storms”), from Latin oceanus (“ocean”) + procella (“storm”). Coined by Italian Jesuit astronomer Giovanni Battista Riccioli, by labelling a map created by Italian Jesuit optician Francesco Maria Grimaldi, and then published in 1651 in the Almagestum Novum.

calque

(planetology) A basin in Nearside, Moon, Earth, Solar System.

en:Francesco Maria Grimaldi
en:Giovanni Battista Riccioli
en:Ocean of Storms


Sea of Tranquility

the Sea of Tranquility (canonical)
Sea of Tranquillity (alternative)

Calque of Latin Mare Tranquilitātis (spelled with one L), from Latin mare (“sea”)+tranquilitātis (“tranquility”). Coined by Italian Jesuit astronomer Giovanni Battista Riccioli, by labelling a map created by Italian Jesuit optician Francesco Maria Grimaldi, and then published in 1651 in the Almagestum Novum.

(planetology) A basin in Nearside, Moon, Earth, Solar System; location of the first manned moon landing, in 1969.

en:Almagestum Novum
en:Francesco Maria Grimaldi
en:Giovanni Battista Riccioli
en:Sea of Tranquility (disambiguation)


hycean

With densities between those of rocky super-Earths and more extended mini-Neptunes, Hycean planets can be optimal candidates in the search for exoplanetary habitability and may be abundant in the exoplanet population.

2021 August, Nikku Madhusudhan, Anjali A. A. Piette, Savvas Constantinou, “Habitability and Biosignatures of Hycean Worlds”, in Astrophysical Journal:

It's thought that the new classification could accelerate the search for life outside our Solar System for one simple reason: planets that fulfil the criteria to be "Hycean" already dominate the known exoplanet population, which is approaching 4,500.

2021 August 25, Jamie Carter, “Is Alien Life Hiding In Plain Sight? New Class Of 'Hycean' Planet Is Where We Should Look, Say Scientists”, in Forbes:

And learning more about Hycean planets could help scientists find biosignatures, or signs of life, outside of our solar system in the near future.

These hydrogen-rich ocean worlds, or hycean worlds, may be habitable.

2021 September 2, Joshua Colwell, Adrienne Dove, James Cooney, “Hycean Worlds and Nudging Asteroids”, in Walkabout the Galaxy:

TOI-2136b is a sub-Neptune transiting a nearby and bright star (J=10.8) and is a potential hycean planet, making it an excellent target for atmospheric studies to understand the formation, evolution, and habitability of the small planets.

2022 February 21, K KawauchiF MurgasE PalleN NaritaA Fukuiet al., “Validation and atmospheric exploration of the sub-Neptune TOI-2136b around a nearby M3 dwarf”, in arXiv.org, →DOI:

While LTT 1445 Ab is not in the traditional habitable zone of its star (Winters et al. 2019), it is considered as a candidate Hycean world where a liquid ocean may exist underneath a H₂-dominated atmosphere.

2022 September 26, Caprice Phillips, Ji Wang, Billy Edwards, Romy Rodriguez Martinez, Anusha Pai Asnodkar, B. Scott Gaudi, “Is LTT 1445 Ab a Hycean World or a cold Haber World? Exploring the Potential of Twinkle to Unveil Its Nature”, in arXiv, →DOI:

(astronomy, planetology, of a planet, neologism) Having a water-based ocean that covers the entire planet, and an atmosphere rich in hydrogen.


jovicline

From Jove + -cline. From Latin Jovi (“Jupiter”) (Iove, Iuppiter) + clino (“incline”) (gradient). Coined in reference to thermocline and halocline.

(planetology, radio astronomy, astrometeorology) The separation between two different depth layers of the planet Jupiter, where the microwave emission characteristics of the bands (light stripes) and belts (dark stripes) are reversed. Bands have low levels of microwave emissions compared to belts at the surface, while below the jovicline, they have higher emissions comparatively.


cryolava

en-noun

cryolava (countable and uncountable, plural cryolavas)

(planetology, geology, volcanology) Ice-volcanic melt which has erupted from a cryovolcano.


methanosphere

(planetology) The methane-based analogue of an H₂O water-based hydrosphere; a methane hydrosphere.


apoareon

(planetology) Alternative form of apoareion.


periareon

(planetology) Alternative form of periareion.


Jeans escape

Jeans escape (countable and uncountable, plural Jeans escapes)

Named after English physicist Sir James Jeans (1877–1946), who is credited with calculating the rate of such atmospheric escape.

2014, Eugene F. Milone, William J. F. Wilson, Solar System Astrophysics, Springer, 2nd Edition, page 413,
As will be seem in Sects. 11.7.2.3 and 11.7.3.2, Jeans escape of H atoms from Venus is negligible compared to other, nonthermal mechanisms, whereas Jeans escape dominates the loss of H from Mars. On both planets, Jeans escape of O, O₂ and CO₂ is negligible.

where a≡m/2k_BT, n is the number density of particles and v is the magnitude of the velocity.

2017, Kevin Heng, Exoplanetary Atmospheres, Princeton University Press, page 213, The simplest model of Jeans escape [112], a mechanism named after the Englishman James H. Jeans, assumes that the constituent particles of the atmosphere may be described by a Maxwell-Boltzmann distribution, f_M=(a/π)ne, (13.6)

2021, Mark H. Thiemens, Mang Lin, 2: Discoveries of Mass Independent Isotope Effects in the Solar System, Ilya N. Bindeman, Andreas Pack (editors), Reviews in Mineralogy and Geochemistry, Volume 86: Triple Oxygen Isotope Geochemistry, Mineralogical Society of America, page 70,
The hydrogen is lost from the system by diffusion and Jeans escapes.

(planetology, astrophysics) A type of atmospheric escape in which a light gas atom or molecule (typically a helium atom or hydrogen molecule) gains sufficient momentum through collision with other molecules to escape the atmosphere (and gravitational pull) of a planet.


Sea of Moscow

A calque of translingual Mare Muscoviensis (literally “Muscovian Sea”), from New Latin Mare Muscoviensis, from Latin mare (“sea”) + Latin Muscoviensis (“Muscovian, of Muscovy”)

affix

(planetology) A basin in the Moon, orbiting the Earth, in the Solar System.