Translation guide
A group of stars gravitationally bound together, often with planets. In English, 'star system' can refer to a single star with its planets or a multiple-star system. In Japanese, the most common equivalent is 星系 (seikei), but the term 恒星系 (kōseikei) is also used, especially in astronomy. For sci-fi or casual contexts, スターシステム (sutā shisutemu) may appear.
Referring to a gravitationally bound system of one or more stars, possibly with planets, in a scientific or general context.
The standard term for 'star system' in astronomy. It encompasses single-star systems with planets as well as multiple-star systems. Widely used in scientific literature and news.
太陽系は一つの星系です。
The solar system is one star system.
この星系には複数の惑星が存在する。
Multiple planets exist in this star system.
Literally 'fixed star system', emphasizing the star(s) as the central component. More technical and less common than 星系, but used in astronomy to distinguish from planetary systems.
ケンタウルス座アルファ星は三重恒星系です。
Alpha Centauri is a triple star system.
Loanword from English, used in sci-fi, games, or casual contexts. Not standard in scientific Japanese.
このゲームでは、新しいスターシステムを探索できます。
In this game, you can explore new star systems.
Emphasizing that the system contains two or more stars (binary, triple, etc.).
Specifically means 'multiple star system' or 'binary star system'. Use when the multiplicity of stars is the focus.
シリウスは連星系です。
Sirius is a binary star system.
Means 'multiple star system', often for systems with three or more stars. More specific than 連星系.
この多重星系は四つの星から成る。
This multiple star system consists of four stars.
Used in science fiction, games, or storytelling to refer to a fictional group of stars and planets.
Still the most natural term even in fiction. It's neutral and widely understood.
物語は遠くの星系で始まる。
The story begins in a distant star system.
星系 (seikei) is the general term for any star system. 恒星系 (kōseikei) emphasizes the star(s) and is more technical. 太陽系 (taiyōkei) specifically means 'solar system', i.e., our own star system. Do not use 太陽系 for other star systems.
The direct translation '星のシステム' (hoshi no shisutemu) is not used in Japanese. Always use 星系 or 恒星系.
Common in translated sci-fi or games, giving a slightly exotic feel. Acceptable but less formal.
宇宙船は未知のスターシステムにワープした。
The spaceship warped to an unknown star system.