What would be some ways to say "next star", "the next star" or something very similar in Latin?
By next I mean next as in "the next star to visit/conquer/study", not "next" as in the closest one.
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Sign up to join this communityI'd go with stella secunda myself.
The main words for "star" are stēlla, astēr, astrum, and sīdus, with astēr and astrum being borrowings from Greek (and the latter especially being poetic/pretentious) and sīdus primarily meaning "constellation"; stēlla is native, and also the word that survived into the Romance languages, so it strikes me as the most neutral choice.
There are a few options for "next" as well, but secundus (which does also mean "second", of course) seems good to me: it's derived from the verb sequi "to follow" and also generally has positive connotations. Posterus, in contrast, can also mean "inferior" or refer to the last in a series, neither of which feels desirable.
I would say:
Astrum posterum
In contrast with proximus, which is often taken in the sense of "near", posterus means
coming after, following, next, ensuing, subsequent
As @Cairnarvon mentioned, posterus can mean "inferior" (it only means "last" in its superlative form, so that's irrelevant), but the same is true of secundus, which, according to Lewis and Short, can mean: "second in rank, value, etc. [...] With the prevailing idea of subjection or inferiority, secondary, subordinate, inferior."
I chose astrum as opposed to some other words that means star because of its familiarly and consistency with the popular Latin phrase:
Per aspera ad astra
Through hardships to the stars.