Hot stars are blue, cool stars red.

热的星星是蓝色的，冷的星星是红色的。

They are also the coolest stars and appear more orange than red.

它们也是最冷的恒星，颜色看起来更偏向橙色而不是红色。

A slightly hotter star would be a G1, and a slightly cooler star a G3.

更热一些的恒星是 G1，更冷的则是 G3。

Or it might have been a rare kind of cool and dense star called a white dwarf, Lin added.

林补充说，或者这可能是一种罕见的寒冷且致密的恒星，被称为白矮星。

Hotter stars are O stars and cooler stars are M stars.

较热的恒星是 O 星， 较冷的恒星是 M 星。

We've also discovered even cooler stars in the past few decades, and these are assigned the letters L, T, and Y.

在过去的几十年里，我们还发现了更冷的恒星，这些恒星被命名为 L、T 和 Y。

It could have formed in a very cold part of its home star system or around a star cooler than the sun.

它可能是在其星系里非常冷的地方或者比太阳温度低的恒星附近形成。

The hottest are O stars, then B stars which are slightly cooler, down through A, F, G, K, and with the coolest stars being M.

最热的是 O 恒星，然后是温度稍低的B恒星，一直到 A、F、G、K，最冷的恒星是 M。