Scientists can only find them when they are eating away at parts of a partner star or something else falls into them.

科学家们只能在它们吃掉伴星的一部分或者其他东西被吸进去的时候才能找到它们。

But usually they cannot be seen. Scientists can only find them when they are eating away at parts of a partner star or something else falls into them.

科学家只有在它们吞噬其恒星搭档时或其他物体掉入其中时才能发现。