New images taken by the European Space Agency’s VISTA survey telescope reveal two undiscovered stars located in the Trifid Nebula. The VISTA telescope uses infrared red light so that it can peer through the star-dust of the Milky Way Galaxy and look further into the cosmos where astronomers could not see before. In one of the telescope’s surveys, astronomers found Cepheid variable stars at a great distance. These are the first stars discovered that lie on the central plain region of the Milky Way Galaxy located beyond the central bulge.
This discovery was part of a larger program for the purpose of searching for new and hidden stellar objects. The VISTA Variable in the Via Lactea, better known as VVV, returned to the same parts of the sky where normal telescopes before had not been able to see through the dust in the Galaxy. They searched for objects that varied in luminosity as time passed.
Just a small fraction of the enormous VVV dataset has been utilized to form the new snapshot of the Trifid Nebula. This nebula is found in the stellar formation region named Messier 20. It is named the Trifid Nebula because of the ghostly lines that divide its shape into three separate parts when observed through a telescope.
Current pictures of the Trifid Nebula show it in light from the normal visible spectrum. In the visible light portion of the spectrum, the nebula glows bright pink from ionized hydrogen emissions and a hazy shade of blue as light from young stars lights the background. Moreover, huge clouds of near-opaque dust, the dust through which normal telescopes could not see, was present in and around the nebula. However, a picture of Trifid is much different when viewed from the infrared light spectrum. The nebula is just a silhouette of what was seen before of the hydrogen gas clouds. The surrounding dust is much less conspicuous and the bright clouds were unseen.
In the new image taken of the nebula, thick clouds of dust in the protruding disk of the Milky Way Galaxy allow infrared light to get through so that it can be seen by the VISTA telescope. Therefore, a much clearer image is produced. Rather than seeing just towards the Trifid Nebula, the VISTA telescope can peer far beyond into other regions of the galaxy that have never been seen before.
Scientists explained that this picture shows a great example of what wonders can be revealed when viewing star formations through infrared telescopes. Two new stars were discovered during the imaging. Though they seem close to Trifid through the telescope, they are more than seven times further away in reality. The newly discovered stars are called Cepheid variables. These are types of very bright stars that have an unstable nature and fade quickly over time. The pair of new stars, stars which astronomers believe to be the brightest in the entire cluster, are the only Cepheid variables to be found in the area. There are near the central plane of the galaxy, but they are on the far side. Scientists found that the two newly discovered stars in the Trifid Nebula brighten and fade over a period of 11 days.
By: Alex Lemieux
Picture courtesy of Astrorom – Flickr License