Which will eventually form stars of spectral types g , k or m . t tauri stars are surrounded by a huge cloud and they are very young , with low surface temperature . they emit most of their light in the infrared region and they appear red . a general principle is , a violent reaction will give out short wavelength waves , like gamma rays or x - rays ; while a gentle process will radiate long wavelength waves , like radio or infrared ，这类星最后会演化为g k或m型恒星，金牛座t型星为表面温度低而非常年青的恒星，四周被星云所围绕，所以这种星颜色偏红，较容易在红外线波段找到一个普遍的原则是，如果活动越激烈，则所放出的光波波长越短，主要会为伽玛或x射线如果活动温和，则会发放出如无线电波或红外线等长波长电磁波。
