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Image of the day 12/23/2019

Getting plate-solving status, please wait...
    Hartl-Dengel-Weinberger 3 (HDW 3), 





    
        

            Peter Goodhew
    Hartl-Dengel-Weinberger 3 (HDW 3)

    Hartl-Dengel-Weinberger 3 (HDW 3)

    Technical card

    Resolution: 4100x2577

    Frames:
    Astrodon 5nm H-Alpha filter: 76x1800" bin 2x2
    Astrodon Blue: 17x300" bin 1x1
    Astrodon Green: 20x300" bin 1x1
    Astrodon Lum: 39x300" bin 1x1
    Astrodon OIII 3 nm: 51x1800" bin 2x2
    Astrodon Red: 20x300" bin 1x1

    Integration: 71.5 hours

    Astrometry.net job: 3128049

    RA center: 3h 27' 16"

    DEC center: +45° 25' 1"

    Pixel scale: 0.534 arcsec/pixel

    Orientation: 3.812 degrees

    Field radius: 0.359

    Locations: e-Eye, Fregenal de la Sierra, Extramadura, Spain

    Data source: Own remote observatory

    Remote source: e-EyE Extremadura

    Description

    Hartl-Dengel-Weinberger 3 (HDW 3, PK149-09.1, PNG149.4-09.2) is an extremely faint ancient planetary nebula in the constellation Perseus. It is so faint that it is very rarely imaged.
    The progenitor star is the small blue star at the 5 o-clock position just below the large yellow star in HDW 3. The progenitor is not, as one would expect, in the centre of the nebula. This is because it is moving rapidly in a north-westerly direction. It is moving through a dense area of interstellar medium (ISM). This ISM is slowing down HDW 3, creating a shock front and the unusual "braided" appearance. As the star isn't slowed by the ISM it has continued to move and is thus no longer at the centre of HDW 3 and is slowly overtaking HDW 3. This causes the shock front to be brighter as it's getting more ultraviolet radiation, whereas of opposite side of HDW 3 is getting less UV radiation and has become invisible. This movement of the star causes differential excitation of the shell. OIII emission, which requires higher energy of the ionizing radiation than HII emission, only happens close to the star.

    Comments

    Author

    PeterGoodhew
    Peter Goodhew
    License: None (All rights reserved)
    148142
    Like

    Revisions

      Hartl-Dengel-Weinberger 3 (HDW 3), 





    
        

            Peter Goodhew
      Original
      Hartl-Dengel-Weinberger 3 (HDW 3), 





    
        

            Peter Goodhew
      B
    • Final
      Hartl-Dengel-Weinberger 3 (HDW 3), 





    
        

            Peter Goodhew
      C

    B

    crop

    C

    small stars sharpened

    Sky plot

    Sky plot

    Histogram

    Hartl-Dengel-Weinberger 3 (HDW 3), 





    
        

            Peter Goodhew