SC usage of comma

[kramacha1979]

I found this sentence in the OG 11 book

It's a wrong answer for many reasons ..but I was more interested in the usage of comma in this sentence

Although like the planets the stars are ...

Shouldn't we be saying
Although like the planets, the stars are ...

If so, then can although have a phrase such as 'like the planets' instead of a sub-ordinate clause
Essentially I am trying to understand the usage of although

[esledge]

Although is one of the most common subordinating conjunctions, which are always used at the beginning of an adverbial clause. Adverbial clauses are constructed like whole sentences (i.e. subject + verb + (often an) object), and modify the verb of the main sentence. When an adverbial clause appears at the beginning of a sentence, it must be set off from the main sentence by commas.

(The last sentence was an example of that very rule, by the way: When is another subordinating conjunction, adverbial clause appears is a subject-verb pair, and the entire when phrase modifies the main verb must be set off.)

So, yes, you should expect a comma in any sentence beginning with Although. However, the comma would properly follow an entire clause.

So you wouldn't put the comma here, as there is no verb before the comma:
Although like the planets, the stars are ... (WRONG comma placement)

You would put the comma after an entire clause, like this:
Although like the planets the stars are spinning, scientists most frequently study ...

Whether the like the planets comparison ought to be set off by commas is another question. I wasn't able to find an OG question with this combination of although and like, so you might want to revisit the solution to see the use of commas in all 5 choices.