DQ Herculis, or Nova Herculis 1934, was a slow, bright nova occurring in the northern constellation of Hercules in December 1934. This cataclysmic variable star was discovered on 13 December 1934 by J. P. M. Prentice from Stowmarket, Suffolk.[12] It reached peak brightness on 22 December 1934 with an apparent magnitude of 1.5.[3] The nova remained visible to the naked eye for several months.[13]
 RGB composite color image of the shell surrounding the nova DQ Her, made from three narrow band images: Blue = 4800Å, green = Hα at 6563 Å and red = [NII] at 6583 Å. From Santamaria et al. 2020[1] | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hercules |
| Right ascension | 18h 07m 30.25108s[2] |
| Declination | +45° 51′ 32.5646″[2] |
| Apparent magnitude (V) | 1.5[3] - 15.16[4] |
| Characteristics | |
| Spectral type | DBe + M2V |
| Variable type | DQ Her[5] |
| Astrometry | |
| Proper motion (μ) | RA: −0.948[2] mas/yr Dec.: +12.423[2] mas/yr |
| Parallax (π) | 1.9975 ± 0.0237 mas[2] |
| Distance | 1,630 ± 20 ly (501 ± 6 pc) |
| Absolute magnitude (MV) | −6.94[6] |
| Orbit | |
| Period (P) | 0.1936208977 ± 0.0000000017 d[7] |
| Semi-major axis (a) | 0.003 AU |
| Inclination (i) | 86.5±1.6[8]° |
| Details | |
| A | |
| Mass | 0.6[9] M☉ |
| Radius | 0.0121[8] R☉ |
| B | |
| Mass | 0.4[9] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a binary star system consisting of a white dwarf primary with an estimated 60% of the mass of the Sun and a red dwarf secondary with 40% of the Sun's mass.[8] They orbit each other tightly with a period of 4.65 hours.[7] The system shows orbital period variation, possibly due to the presence of a third body.[5] The orbital plane of the pair is inclined by an angle of 86.5° to the line of sight from the Earth, causing the white dwarf to undergo a deep eclipse every orbit.[8]
DQ Herculis is the prototype for a category of cataclysmic variable stars called intermediate polars.[5] The red dwarf has filled its Roche lobe and matter is being drawn off at the rate of 2.7 × 10−9 M☉ yr−1, forming an accretion disk orbiting the primary. This disk has inferred temperatures ranging from 5,000 to 13,500 K. A bright spot in the inner disk appears to pulsate with a 71-second period. In this class of variables, the white dwarf is magnetized, directing infalling matter onto the magnetic poles.[8]
The shell of ejected material from the nova outburst is visible as an emission nebula, similar in appearance to a planetary nebula. This roughly elliptical nebula had a size of 32.0 × 24.2 arc seconds as of 2018, and it is expanding at a rate of about 0.16 arc seconds per year.[1]
In popular culture
The nova was one of the brightest objects observable in the night sky. In addition to scientific articles, and received significant coverage in popular news publications.[14][15] Brad Ricca, an English professor at Case Western Reserve University, has suggested that Nova Herculis may have influenced the development of the origin story of the comic book superhero Superman.[16]