DN Geminorum

DN Geminorum
Location of DN Geminorum (circled in red)
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 mas[1]
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]

  1. ^ a b c d e Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d e f g Cite error: The named reference Selvelli2019 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Pettersen2012 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Yerkes1912 was invoked but never defined (see the help page).
  6. ^ a b c d Cite error: The named reference Retter1999 was invoked but never defined (see the help page).