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Getting plate-solving status, please wait...
Kohoutek 1-16, 





    
        

            astroian
Kohoutek 1-16

Kohoutek 1-16

Technical card

Resolution: 1387x900

Dates:July 31, 2019Aug. 2, 2019Aug. 7, 2019Aug. 10, 2019Aug. 15, 2019Aug. 19, 2019Aug. 20, 2019Aug. 22, 2019Aug. 23, 2019Aug. 25, 2019Aug. 26, 2019Aug. 29, 2019Sept. 1, 2019Sept. 5, 2019

Frames:
Astrodon Blue E-Series Gen2 1.25": 15x120" -25C bin 3x3
Astrodon Green E-Series Gen2 1.25": 15x120" -25C bin 3x3
Astrodon Ha 1.25 3nm: 42x600" -25C bin 3x3
Astrodon N2 1.25" 3nm: 42x600" -25C bin 3x3
Astrodon O3 1.25 3nm: 42x600" -25C bin 3x3
Astrodon Red E-Series Gen2 1.25": 15x120" -25C bin 3x3

Integration: 22.5 hours

Avg. Moon age: 16.41 days

Avg. Moon phase: 43.49%

Bortle Dark-Sky Scale: 5.00

Astrometry.net job: 3043799

RA center: 275.464 degrees

DEC center: 64.366 degrees

Pixel scale: 0.670 arcsec/pixel

Orientation: 92.564 degrees

Field radius: 0.154 degrees

Data source: Backyard

Description

This is my image of K1-16, a planetary nebula in the constellation of Draco, between 5200 to 7000 light years away. I have yet to come across much information about the PNe itself, other than its size which is put at between 1.6’ to 2’ across. It lies in front of a very distant galaxy cluster and to the south (left in my image) there is a bright 14th mag quasar, HB89 1821+643 which is part of the cluster. The quasar is 3.3 billion light years away but almost as bright as the central star of K1-16 which puts the power of quasars into perspective.

The central star is DS Dra and judging by the number of professional papers it is of great interest to professional astronomers. It is classed as a PG1159 variable star, one of 20 such stars and only one of 7 which are the central star of PNe. These types of stars exhibit a small amount of variability (~±0.01 magnitudes) which comes and goes.

It’s also hydrogen deficient and carbon rich, showing the same kind of spectra as WR stars. WR stars are normally very heavy, but as the central star of a PNe (CSPN), DS Dra must have been below 8 solar masses to start with, which is much lighter than most WR stars. It is thought to have just finished it’s AGB phase and is now transitioning to a white dwarf. There is a suggestion that it underwent a late Helium flash which dredged up and expelled a load of Carbon into the surrounding environment. The current mass is reckoned to be about 0.65 solar, with a surface temperature of 140,000K. This high surface temperature probably explains the high terminal velocity of the winds blown off this star. They have been measured at about 3800km/s. The mass loss rate is now fairly low, estimated at ~10-8 solar/year. This fits in with the expected behaviour of a post AGB star.

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astroian
astroian
License: None (All rights reserved)
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Kohoutek 1-16, 





    
        

            astroian