| Atomic Mass | Mass Excess |
| 257.107859003846 amu | 100.47 MeV |
| Level energy (MeV) | Spin & parity | Half-life | Mode of decay | Branch ratio (%) | Decay energy (MeV) |
| Ground state | 0.76 S +0.15-0.11 | A | >=94.00 | 9.31 | |
| Ground state | 0.76 S +0.15-0.11 | SF | <=6.00 | 0 | |
| Ground state | 1.50 S +0.19-0.15 | A | >=81.00 | 9.31 | |
| Ground state | 1.50 S +0.19-0.15 | SF | 19 | 0 |
There is no gamma-rays or the intensities are so weak!