Astronomy:DN Geminorum

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Short description: Star in the constellation Gemini
DN Geminorum
DNGemLocation.png
Location of DN Geminorum (circled in red)
Observation data
Equinox J2000.0]] (ICRS)
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
Distanceapprox. 4,500 ly
(approx. 1,400 pc)
Absolute magnitude (MV)5.02±0.60[2]
Details
White dwarf
Mass0.93±0.15[2] M
Other designations
Nova Gem 1912, Nova Geminorum II[3], DN Gem, HD 50480[4]
Database references
SIMBADdata
The light curve of DN Geminorum, plotted from AAVSO data

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]

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

  1. 1.0 1.1 1.2 1.3 1.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 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, doi:10.1051/0004-6361/201834238, A186, Bibcode2019A&A...622A.186S. 
  3. 3.0 3.1 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, doi:10.3724/SP.J.1440-2807.2012.03.08, Bibcode2012JAHH...15..246P. 
  4. "DN Gem". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=DN+Gem. 
  5. 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. 
  6. 6.0 6.1 6.2 6.3 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, doi:10.1046/j.1365-8711.1999.02704.x, Bibcode1999MNRAS.308..140R.