21 Per
21 Per
21 Per is a B-type (Blue-White) star located in the constellation Perseus. It carries the designation 21 Per.
Located approximately 319.8 light-years from Earth, 21 Per resides within the broader disk of our Milky Way galaxy.
21 Per is classified as a spectral class B star (B-type (Blue-White)) on the Harvard spectral classification system.
With an apparent magnitude of +5.10, 21 Per sits near the limit of naked-eye visibility. It can be glimpsed without optical aid under dark skies, but binoculars will make observation much easier. Observers will note its blue hue, which corresponds to a B-V color index of -0.007.
Đặc tính vật lý
| Phân Loại Quang Phổ | B Class B — B-type (Blue-White) |
| Chỉ số màu (B−V) | -0,007 |
Quan sát
| Cấp Sao Biểu Kiến | +5.10 |
| Cấp Sao Tuyệt Đối | 0,14 |
| Khoảng Cách | 320 ly |
| Chòm Sao | Perseus |
Vị trí
| Xích kinh | 2h 57,29m |
| Xích vĩ | 31° 56,05′ |
Frequently Asked Questions
What type of star is 21 Per?
21 Per is a Class B — B-type (Blue-White) star.
How far is 21 Per from Earth?
21 Per is approximately 319.8 light-years from Earth.
Can you see 21 Per with the naked eye?
With an apparent magnitude of 5.10, 21 Per is visible to the naked eye.
What constellation is 21 Per in?
21 Per is located in the constellation Perseus.