DN Geminorum
DN Geminorum or Nova Geminorum 1912 was a classical nova which lit up in 1912 in the constellation Gemini. It was discovered by Norwegian variable star observer Sigurd Einbu[3] on March 12, 1912 before reaching peak brightness, which allowed early-stage spectra to be collected by Yerkes Observatory.[5] The nova reached a maximum brightness of around 3.5 mag before declining,[6] which means it was visible to the naked eye. Its brightness decreased over the following 36 days by 3 magnitudes as it gradually faded from sight. The light curve saw two maxima a few months after the outburst, along with strong oscillations.[6] Today its brightness is visual magnitude 15.5.[2]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Gemini |
| Right ascension | 06h 54m 54.34929s[1] |
| Declination | +32° 08′ 27.9247″[1] |
| Apparent magnitude (V) | 15.5±0.5[2] |
| Astrometry | |
| Proper motion (μ) | RA: −0.794[1] mas/yr Dec.: −4.323[1] mas/yr |
| Parallax (π) | 0.7288 ± 0.0807[1] mas |
| Distance | approx. 4,500 ly (approx. 1,400 pc) |
| Absolute magnitude (MV) | 5.02±0.60[2] |
| Details | |
| White dwarf | |
| Mass | 0.93±0.15[2] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a close binary star system consisting of a white dwarf with 93%[2] of the Sun's mass – the source for the nova explosion – and a lower mass red dwarf[6] companion from which the white dwarf is accreting matter.[2] The system is located approximately 4,500 light years from the Sun based on parallax, with its visual magnitude being diminished by an extinction of 0.53±0.12 due to interstellar dust.[2] Observations of this system showed a sinusoidal variation in luminosity with a period of 3.06840 ± 0.00012 h, which is likely the orbital period for the pair. This oscillation may be caused by irradiation of the companion star by the white dwarf.[6]
References
- Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- Selvelli, Pierluigi; Gilmozzi, Roberto (February 2019), "A UV and optical study of 18 old novae with Gaia DR2 distances: mass accretion rates, physical parameters, and MMRD", Astronomy & Astrophysics, 622: 16, arXiv:1903.05868, Bibcode:2019A&A...622A.186S, doi:10.1051/0004-6361/201834238, S2CID 119234563, A186.
- Pettersen, Bjørn Ragnvald (November 2012), "Sigurd Enebo and Variable Star Research: Nova Geminorum 1912 and the RV Tauri Stars", Journal of Astronomical History and Heritage, 15 (3): 246–254, Bibcode:2012JAHH...15..246P.
- "DN Gem". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-08-15.
- Yerkes Observatory (June 14, 1912), "Note on Nova Geminorum 1912", Monthly Notices of the Royal Astronomical Society, 72 (8): 675–676, doi:10.1093/mnras/72.8.675.
- Retter, A.; et al. (September 1999), "An irradiation effect in Nova DN GEM 1912 and the significance of the period gap for classical novae", Monthly Notices of the Royal Astronomical Society, 308 (1): 140–146, arXiv:astro-ph/9905375, Bibcode:1999MNRAS.308..140R, doi:10.1046/j.1365-8711.1999.02704.x, S2CID 14377631.
