How to use * to search the word with dash under cursor?

for example the text is like this
```
a-b
b-c
a-b

```


if the cursor is on the first line first column (on `a` now). And then I press `*` I want to find the `a-b` but the vim just search `a` instead of `a-b`, so how to make * to include the dash `-`?

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