 GK Persei and the surrounding Firework Nebula. | |
| Observation data EpochJ2000.0 EquinoxJ2000.0 | |
|---|---|
| Constellation | Perseus |
| Right ascension | 03h 31m 11.82s[1] |
| Declination | +43° 54′ 16.8″[1] |
| Apparent magnitude (V) | 0.02[2] - 14.0[3] |
| Characteristics | |
| Spectral type | K1IV[4] |
| Astrometry | |
| Radial velocity (Rv) | 5.5[5] km/s |
| Proper motion (μ) | RA: −6.878[6]mas/yr Dec.: −17.348[6]mas/yr |
| Parallax (π) | 2.3063±0.0415 mas[6] |
| Distance | 1,440+29 −26 ly (442+9 −8[2] pc) |
| Absolute magnitude (MV) | −9.1 - +3.7[2] |
| Orbit[7] | |
| Period (P) | 1.996872 ± 0.000009 d |
| Inclination (i) | 67 ± 5° |
| Semi-amplitude (K2) (secondary) | 126.4 ± 0.9 km/s |
| Details[7] | |
| White dwarf | |
| Mass | 1.03+0.16 −0.11 M☉ |
| Subgiant | |
| Mass | 0.39+0.07 −0.06 M☉ |
| Radius | 2.26 ± 0.11 R☉ |
| Other designations | |
| GK Per, Nova Per 1901,HD 21629,HR 1057,BD+43 740a,2MASS J03311201+4354154,1RXS J033111.9+435427[8] | |
| Database references | |
| SIMBAD | data |
GK Persei (alsoNova Persei 1901) was a brightnova first observed on Earth in 1901. It was discovered byThomas David Anderson, anEdinburgh clergyman, at 02:40 UT on 22 February 1901 when it was atmagnitude 2.7.[9][10] It reached a maximum magnitude of 0.2, the brightest nova of modern times untilNova Aquilae 1918. After fading into obscurity at about magnitude 12 to 13 during the early 20th century, GK Persei began displaying infrequent outbursts of 2 to 3 magnitudes (about 7 to 15 times quiescent brightness). Since about 1980, these outbursts have become quite regular, typically lasting about two months and occurring about every three years. Thus, GK Persei seems to have changed from a classical nova like Nova Aquilae 1918 to something resembling a typicaldwarf nova-typecataclysmic variable star.
Surrounding GK Persei is the Firework Nebula, anova remnant first detected in 1902 consisting of an expanding cloud of gas and dust bubbles moving up to 1200 km/s.[11]
GK Persei has precise parallaxes reported fromGaia DR2 andGaia EDR3,[12][6] but these are thought to be badly affected by the binary nature of the system. TheHubble Space Telescope has used a different method to derive the distance to GK Persei using nebular expansion velocity and compares that with its own astrometric parallax calculation. This gave a somewhat smaller parallax (larger distance) than theGaia measurements.[13]
Nova Persei, as it was then called, was the first nova exhibiting so-calledsuperluminal motion of the ejecta. That this was the case was noted byJacobus Kapteyn in December, 1901, on the basis of estimates of its distance from Earth.[14]
Novae consist of a main-sequence to giant star that accretes mass onto awhite dwarf. The two stars of GK Persei orbit each other with a period of nearly 2 days. The white dwarf, with a mass of 1.03 M☉, has one of the highest masses measured in a cataclysmic variable. The donor star, having donated much of its mass to the white dwarf, is only 0.39 M☉ despite being asubgiant star.[7]
