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Nova V1494 Aquilae

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Date:04.12.99 Time:17:40 UT Exposure:45 s
Field of View:73o x 53o Emulsion:Kodak Royal 1000 Select Filter:none
Optics:f=24mm 1/2.8 Place:Lippstadt Observer:T. Credner
Notes to the data

© Copyright by the observers

On December the 1st 1999 a Nova was found by the portuguese amateur astronomer Alfredo Pereira (IAU Circular 7323). This new appearing star had a brightness of 6 mag and increased up to about 3.9 mag at 3rd of December. Thus it became quite easily visible to the naked eye. The above photography from the 4th shows the Nova in the constellation of Aquila with a brightness of about 4.7 mag. This star is of course not really new, a predecessor could be found on Palomar Schmidt plates with a brightness of about 16 mag. It means that the star intensity increased by a factor of 70.000 !

A Nova originates from an interacting binary star. A compact and dense white dwarf can accrete mass by its close companion, a normal main sequence star. The companion has such a critical large radius and small distance to the dwarf that mass can flow to the white dwarf and builds up an accretion disc around it. The disc material looses energy due to friction, spirals inward and rains onto the dwarfs surface. If this hydrogen rich material reaches a critical mass on the white dwarfs surface a nuclear hydrogen burning starts explosively. This gives the outburst in luminosity and the often observed expanding shells in Novae and their remnants.

  • Astronomy Picture of the Day, December 15, 1999, NASA
  • More detailed view of V1494 Aql and comparison with former image
  • Frequently updated lightcurve of V1494 Aql by the BAV