New research from UK Infra-Red Telescope reveals numerous unknown jets of gas from young stars and planetary nebulae and may prompt significant changes in the understanding of the planetary nebulae population in the Galaxy.
For many years astronomers have known that young ‘protostars’ drive supersonic jets of gas from their north and south poles. However, this is the first time that so many of them have been detected at once.
The results come from a five year survey undertaken with the UK Infra-Red Telescope and are expected to prompt significant changes in the understanding of the planetary nebulae population in the Galaxy, as well as the properties of jets ejected from young forming stars.
By examining images of excited hydrogen molecules at infrared wavelengths, scientists have been able to see through the gas and dust in the Milky Way in order to observe more distant targets. These targets are normally hidden from view and many of them have never been seen before.
The entire survey area covers approximately 1450 times the size of the full moon, or the equivalent of a 95 GigaPixel image. The survey reveals jets from protostars and planetary nebulae, as well as supernova remnants, the illuminated edges of vast clouds of gas and dust, and the warm regions that envelope massive stars and their associated clusters of smaller stars.
Based on current estimates using these data, the project expects to identify about 1000 unique jets from young stars – at least 90% of these are new discoveries – as well as 300 planetary nebulae, with almost half of them unknown.
Dr Dirk Froebrich of the University’s Center for Planetary Science said: ‘These discoveries are very exciting. We will ultimately have much better statistics, meaning we will be able to investigate the physical mechanisms that determine the jet lengths, as well as their power. This will bring us much closer to answering some of the fundamental questions of star formation: How are these jets launched and how much energy, mass and momentum do they feed back into the surrounding interstellar medium.’
To mark the 5th anniversary of the start of the observations of the survey on 27 August, the project has released a number of images taken with the UK Infra-Red Telescope, based in Hawaii and used for the research.
All the above images are generated by combining data with observations taken by UKIDSS. The images are false color representation of the objects in the near infrared part of the spectrum and the three color channels are represented by the following wavelength: Blue: broad band emission at 1.2micrometer; Green: broad band emission at 2.2micrometer; Red: Emission of molecular hydrogen at 2.122micrometer. Based on this color-code, objects that contain hydrogen molecules emitting at 2.122micrometer appear very red. The color of all other objects gives a rough indication of their temperature. Hotter objects appear bluer, while cooler objects are redder.
Images: University of Kent