Questions tagged [nomenclature]

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26 votes
3 answers
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Why do some supermassive black holes have a * in their name?

Sgr A*, M87*,... Several supermassive black holes (SMBHs) at the center of galaxies have a star (*) in their name. But many others do not. Is there a physical difference between the SMBHs that are ...
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4 votes
2 answers
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Is the satellite of a small star in a binary solar system a moon or a planet?

What exaclty distinguishes a moon from a planet? In a binary solar system that has a large star in the center and a smaller star - among some planets - orbiting that large star, and the smaller star ...
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3 votes
1 answer
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Are there dwarf planets that aren't minor planets?

This diagram makes it look like there are dwarf planets that aren't minor planets. Is this indeed the case, or am I misreading the diagram? If there are dwarf planets that aren't minor planets, what ...
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6 votes
3 answers
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Nomenclature of Interstellar Objects and Stars

I posted this question on the space exploration SE but people recommended that it would be more on-topic here. Could someone please help by giving some definite laws of nomenclature for celestial ...
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3 votes
1 answer
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Since Proxima Centauri orbits the other two Alpha Centauri stars, will it eventually be farther away from us than they are?

And, if so, will we have to change its name to Distal Centauri ;-) ? Granted, its orbital period around the other two is about 550,000 Earth years, so we have some time....
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2 votes
2 answers
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How does one go about submitting a name for a newly-discovered lunar crater?

Suppose I discover an uncatalogued crater on the lunar surface, and decide to name it. How would I submit my proposed name to the IAU?
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1 answer
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Who coined the phrase "martian dichotomy"?

This question is adjacent to this other one. The martian dichotomy refers to the fact that the northern and southern hemisphere are radically different on Mars, with different surface ages and ...
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16 votes
1 answer
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The newly discovered comet NEOWISE has been given the name C/2020 F3. What is the meaning of the F3 and the C in this name?

The new comet C/2020 F3 was first spotted by NASA's NEOWISE satellite in March 2020. It is now visible in the NE sky just before dawn. The C may refer to it's non-periodic nature (so far). What does ...
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22 votes
1 answer
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What would an asteroid inside of Mercury's orbit be called?

The first Vatira asteroid has been discovered. This makes me wonder if there is already a name for the hypothetical class of asteroids that orbit entirely inside of Mercury's orbit. It wouldn't be the ...
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2 votes
0 answers
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Why was the diaeresis removed from Pasiphae?

The Gazetteer of Planetary Nomenclature notes that the spelling of Jupiter's moon Pasiphae was changed from Pasiphaë in July 2009, i.e. they removed the diaeresis. I've been unable to track down the ...
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2 votes
1 answer
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Where do the symbols $\lambda$ and $\beta$ come from for celestial latitude and longitude?

I'm reading Episodes From the Early History of Astronomy, and the author mentions the system of celestial coordinates based on the ecliptic. In this system, the two coordinates are latitude and ...
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1 vote
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What are the correct symbols for vernal and autumnal equinox?

What are the correct symbols for vernal and autumnal equinox? I have seen people use both ♈︎ (\Aries) and $\gamma$ (\gamma) to denote vernal equinox. However, I have never seen the symbol for ...
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1 vote
1 answer
108 views

Why are only some of the geologic features in Mars' Noctis Labyrinthus region named?

I found this page Names Approved for Six Cavi and a Tholus on Mars which lists seven features on Mars. I'm curious about the decisions to name only these features: Dalu Cavus, Layl Cavus, Malam Cavus, ...
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