Definition
GK Persei, also designated Nova Persei 1901, is a cataclysmic variable star system consisting of a white dwarf and a subgiant donor star. It was observed as a bright nova eruption in February 1901 and is now surrounded by an expanding nebular shell known as the Firework Nebula.
Overview
Located in the constellation Perseus at right ascension 03ʰ 31ᵐ 11.82ˢ and declination +43° 54′ 16.8″ (J2000), GK Persei is visible to the naked eye at its peak (apparent magnitude ≈ 0.2) and fades to about magnitude 12–13 in quiescence. After the 1901 nova event, the system entered a phase of recurrent dwarf‑nova‑like outbursts beginning in the 1980s, typically rising 2–3 magnitudes for roughly two months every three years. The binary orbital period is 1.996872 days, and the system is classified as an intermediate polar (a magnetic cataclysmic variable).
Etymology / Origin
The variable‑star designation “GK Persei” follows the standard nomenclature for variable stars, where the letters G, H, …, Z, then AA, AB, … are assigned sequentially within a constellation; “Persei” indicates the constellation Perseus. The historical name “Nova Persei 1901” reflects its discovery as a nova in the year 1901.
Characteristics
| Property | Value | Notes |
|---|---|---|
| Spectral type | K1 IV (subgiant donor) | The donor star contributes most of the optical light in quiescence. |
| White dwarf mass | ≈ 1.03 M☉ | Among the highest masses measured for cataclysmic‑variable white dwarfs. |
| Donor star mass | ≈ 0.39 M☉ | Despite being a subgiant, it has lost substantial mass to the white dwarf. |
| Distance | ≈ 1 440 ly (≈ 442 pc) | Determined from nebular expansion studies; Gaia parallaxes are affected by binarity. |
| Orbital period | 1.996872 d | Determined from radial‑velocity and photometric studies. |
| Inclination | ≈ 67° ± 5° | Derived from spectroscopic modeling of the binary orbit. |
| Outburst behavior | Dwarf‑nova‑like eruptions every ~3 yr since ~1980 | Peaks 2–3 mag above quiescence, lasting ~2 months. |
| Nebular shell | “Firework Nebula”, expanding at up to ~1 200 km s⁻¹ | First nova remnant imaged; exhibits knots and filaments created by the 1901 eruption. |
| Magnetic field | Intermediate‑polar classification | The white dwarf’s magnetic field channels accretion flow, producing X‑ray pulsations. |
Related Topics
- Nova – a thermonuclear explosion on the surface of a white dwarf accreting material from a companion.
- Cataclysmic variable (CV) – a binary system where a white dwarf accretes matter from a donor star, producing variability.
- Intermediate polar (DQ Her star) – a subclass of CVs with moderately magnetic white dwarfs, leading to asynchronous rotation and X‑ray pulsations.
- Firework Nebula (Nova Persei 1901 remnant) – the expanding gaseous shell surrounding GK Persei, observable in optical and X‑ray wavelengths.
- Dwarf nova – a type of CV that undergoes semi‑regular outbursts due to accretion‑disk instabilities; GK Persei’s post‑1901 behavior aligns with this class.
All information is based on peer‑reviewed astronomical literature and the consensus data available in reputable sources such as the peer‑reviewed journals, the SIMBAD astronomical database, and the Wikipedia entry for GK Persei.