An international team of astronomers led by members of the Laboratory for Space Research (LSR) and Department of Physics at The University of Hong Kong (HKU), have discovered a rare celestial jewel–a so-called Planetary Nebula (PN) inside a 500 million-year-old Galactic Open Cluster (OC) called M37 (also known as NGC2099).
An international team of astronomers led by members of the Laboratory for Space Research (LSR) and Department of Physics at The University of Hong Kong (HKU), have discovered a rare celestial jewel–a so-called Planetary Nebula (PN) inside a 500 million-year-old Galactic Open Cluster (OC) called M37 (also known as NGC2099). This is a very rare finding of high astrophysical value. Their findings have just been published in the prestigious open-access paper Astrophysical Journal Letters.
PNe are the ejected, glowing shrouds of dying stars that shine with a rich emission line spectrum and display, as a result, their distinct colours and shapes that make them photogenic magnets for public interest. It was no coincidence that one of the first James Webb Space Telescope (the largest optical telescope in space) images released to the public was a PN!
The PN, with the rather ungainly name of “IPHASX J055226.2+323724”, is only the 3rd example of an association between a PN and an OC out of the ~4,000 PNe known in our Galaxy. It also appears to be the oldest PN ever found. The small team led by Professor Quentin PARKER, Director of the HKU LSR, have determined some interesting properties for their discovery: the authors found the PN has a “kinematic age” of 70,000 years. This estimate is based on how fast the nebula is expanding, as determined from the PN emission lines, and assuming this speed has remained effectively the same since the beginning, and is the time elapsed since the nebular shell was first ejected by the host, a dying star. This compares to typical PN ages of 5,000-25,000 years. It is truly a grand old dame in PN terms but of course a mere “blink of the eye” in terms of the life of the original star itself that runs to hundreds of millions of years.
Read more at The University of Hong Kong
Image: A contrast enhanced 30°ø30 arcminute quotient (Hα−r band) IPHAS (Drew et al. 2005) mosaic centred on the core of Galactic open cluster M 37 (NGC 2099). The low surface brightness bipolar PN (IPHASX J055226.2+323724) is encompassed by a red circle with a diameter of 445 x 10 arcseconds (the nebular major axis) while the blue circle indicates the full ∼ 30 arcminute extent of the cluster. The PN is well within the cluster tidal radius with the blue CSPN at almost the precise geometric centre of the PN. The CSPN is itself only ∼280 arcseconds from the published cluster center position. (Credit: The University of Hong Kong)
