Based on the temperature of 3,150 K, Luyten's Star would be classified as a spectral type M. Spectral types are categorized as follows:
- O: > 30,000 K
- B: 10,000 - 30,000 K
- A: 7,500 - 10,000 K
- F: 6,000 - 7,500 K
- G: 5,200 - 6,000 K
- K: 3,700 - 5,200 K
- M: < 3,700 K
Since 3,150 K falls below 3,700 K, it fits into the M spectral type category.