NGC 1999 is a dust-filled nebula with a vast hole of empty space in the center. It is a reflection nebula illuminated by the light of the variable star V380 Orionis.
It was previously believed that the black patch was a dense cloud of dust and gas which blocked light that would normally pass through. However, when Herschel observed the space, itresulted in continued black space. This led to the belief that either the cloud material was immensely dense or that an unexplained phenomenon had been detected.
With support from ground-based observations done other ground-based telescopes, it was determined that the patch looks black not because it is an extremely dense pocket of gas, but because it is truly empty. The exact cause of this phenomenon is still being investigated, although it has been hypothesized that narrow jets of gas from some of the young stars in the region punctured the sheet of dust and gas, as well as, powerful radiation from a nearby mature star may have helped to create the hole.
Image:
Details:
All data was taken by Hubble’s Wide Field Planetary Camera 2 (WFPC2) from the following proposal: https://archive.stsci.edu/proposal_search.php?mission=hst&id=8548
Red: hst_08548_01_wfpc2_f675w_wf
Green: hst_08548_01_wfpc2_f555w_wf
Blue: hst_08548_01_wfpc2_f450w_wfProcessing:
- Chanel combination
- Color calibration
- ArcsinH stretch
- Local Histogram Equalization
- MMT noise reduction
- MLT sharpening
- Curves adjustments