Notes on Astro Symbols

The following is an incomplete list of objects in the Solar System, along with their namesakes and symbols.

The symbols for the major planets, the Sun, Luna, Ceres, Pluto, and the early-discovered asteroids are all official and recognized by astronomers. (This is because all of these objects were at one point considered planets.) The symbols for the other dwarf planets, the moons of other objects, etc. are unofficial. These mostly come from public domain designs by Denis Moskowitz. The designs for Europa, Ganymede, Callisto, and Orcus are my own designs (also public domain).

All of the astronomical symbols in the table below are copypasteable.

• If an astronomical symbol is in black, then it’s an official part of the unicode standard.
• If a symbol is in blue, then it is implemented in the Private Use Area of the Catrinity font. You’ll need that specific font installed to use these characters.
• If a symbol is in red, then it’s a symbol I’ve jankily implemented in webfont form.

Please don’t treat this as an authoritative source on either Greco-roman mythology nor astronomy. I have some links at the end. But the source for a lot of these snippets is “something I remember hearing from a Youtube video”.

¶ The Eight Major Planets

¶ The Dwarf Planets

(Personally, I liked Asimov’s terminology suggestion of “Major Planet” for the big 8, “Minor Planet” for peedie things like comets and asteroids, and “Mesoplanet” for the Plutos and Cereses of the the system.)

And the following are a few of the objects most likely to be dwarf planets, which haven’t been recognized by the IAU as such:

¶ The Moons

Aka “satellite planets”. The word “moon” originally just referred to Luna, the moon of earth, and comes from a Proto-Indo-European word related to timekeeping and the month.

¶ Planetary Mass Moons

Here are the moons bigger than Pluto, and which would at the very least be classified as dwarf planets were they not orbiting around another body (in fact, Titan and Ganymede are even bigger than Mercury):

And here are a few more moons which are maybe big enough to probably count as dwarf planets, even if they aren’t as dramatically large as the previous list. Well, Enceladus is teeny tiny, but it’s round and interesting enough that it seems to fit in with this list.

¶ Tiny Lumpy Moons

Here are a few more moons which aren’t big enough to be properly rounded, but are ‘famous’ enough to mention.

Mars’ itty bitty teensy weeny moons, for example, are no more than a couple dozen km across, but they’re notable for being so close to the surface of Mars that they appear large in the Martian sky.

¶ Theorized Planets

¶ The Sun

¶ The Minor Planets

These are now properly called “small solar system bodies”.

People initially considered these planets and gave them symbols. Around the discovery of 16 Psyche is when astronomers realized there are too many of the dang things to dote on each one individually, and just started giving them numbers.

Below, I’ve listed the first batch discovered, as well as some notable objects discovered later on. A much much more comprehensive list can be found here.

</table><tr><td class="catsym">486958 Arrokoth</td><td>Peanut shaped object out past Pluto. It’s the most distant object yet to have been visited by a spacecraft. The name means “cloud”.</td></tr> </table>

¶ Other Space Whatsits

ʻOumuamua

The first known interstellar object to visit the Solar System.

Its name means something like “scout”. Probably not aliens, but for a while there, that wasn’t a completely ludicrous hypothesis.

Likely a chunk of solid nitrogen broken off from some other system’s equivalent of Pluto, hurled into the cosmic void, and eroded by cosmic rays.

2019 OK

An Apollo-class object that passed close to the Earth in 2019. Because of the angle of its orbit, we had very little warning about its approach.

The name is just based on the date of its discovery, and doesn’t follow the normal asteroid number naming pattern.

¶ Constellations

These aren’t actually objects so much as they’re regions of the sky.

¶ Various Other Astro Symbols

• Symbols for the relative positions of objects: ☊☋☌☍⚹⚺⚻⚼⯳⯴⯵⯶⯷⯸
• Some fortune-teller-types use “Lilith” and “Priapus” to refer to the Moon’s perigee and apogee. (Nearest and farthest orbital points from the Earth.) ⚸⯞ Lilith is either a primordial demon or the first woman, sculpted from the same clay as Adam. Priapus is a minor fertility god, most notable for his large… endowment.
• Then there’s also “White Moon Selena” and “True Light Moon Arta” ⯝⯟, astrological points which have some sort of connection to the moon’s orbit. I tried following the citations from the unicode documents, but the page I ended up at gave off powerful Time Cube energy.
• Speculating about a major planet out past Pluto is a popular hobby, and astrologers haven’t skipped out on the fun.
  • ⯗ Generic Transpluto Planet: This character is listed in the unicode standard simply as “Transpluto”.
  • ⯘ Proserpina: Same namesake as asteroid 26, but otherwise no connection. (But yeah, dang. Given the myth, maybe that name should have been saved for an eccentric Kuiper belt object, like a comet or something.)
  • There’s also ⯠ Cupido, ⯡ Hades, ⯢ Zeus, ⯣ Kronos, ⯤ Apollon, ⯥ Admetos, ⯦ Vulcanus, and ⯧ Poseidon .
    • Most of those are just alternate names for gods that already had a planet or asteroid named after them. I do have to admit, however, that the symbol for Vulcanus is super snazzy.
    • The odd one out here is Admetos. His story is that Apollo loved this guy a lot, and so when he learned that Admetus was soon fated to die, Apollo convinced the fates to let someone else die in his place. But oh no, his wife Alcestis is the one who volunteers to die! Ironic tragedy! It all works out in the end because Heracles stops by, wrassles Thanatos into submission, and brings Alcestis back to the world of the living.
• Stars and comet: ★☆☄.
• An eclipse and a crescent: 

¶ My designs:

Jupiter’s Symbol is the letter zeta crossed with Jupiter’s staff. These symbols for E Europa, G Ganymede and C Callisto - all watery moons of Jupiter - take the first greek letter of the moon’s name (γ,ε,ϰ), and cross it with with a line. Moskowitz’ symbols for these moons are similar, but with capital letters. The minuscule versions of the letters just felt more spacey to me.

Plus, as a bonus, this version of the Europa symbol looks vaguely like a bull’s horns, and a lowercase gamma looks a bit like a bird.

Then just as PLuto’s symbol is a combination of P and L, this symbol for O ORcus is a combination of O and R, (arranged to look like a scary monster eyeball.)

Update 2022: Denis Moskowitz' design, 🝿, has been enshrined into the unicode standard. I'm still found of my design, though. And besides, Pluto has multiple symbols; Orcus, as the anti-Pluto, should have multiple symbols as well.

¶ Relevant Links:

• Object Info:
  • List of names of astrobodies, and their associations from the USGS.
  • NASA Planetary Fact Sheet
  • Physical data for Moons
  • Wikipedia - List of gravitationally rounded objects of the Solar System
  • JPL Small-Body Database Browser
  • IAU Minor Planet Center
  • Astrum youtube channel
  • Anton Petrov youtube channel
  • Diagramatic Planet Position Viewer
• Symbols:
  • Wikipedia - Astronomical Symbols has all of the official ones.
  • Wikimedia - Asteroid Symbols
  • New astro symbols, by Denis Moskowitz. (A couple have actually made it into the unicode standard.)
  • Catrinity font
  • The charts with the codepoints of the astro symbols: Unicode1, Unicode2, Catrinity. (ctrl+f “astro”)
  • The janky font I made for moon symbols.
• Namesakes:
  • Overly Sarcastic - Miscellaneous Myths
  • Quaoar faq
  • Gazetteer of Planetary Nomenclature
• Other:
  • Space tourism posters
  • This old janky nasa.gov subsite for kids.
  • XKCD planet surface area comparison