Gaia's view of a dark nebula in Orion
The Orion A portion of the Orion Molecular Cloud, a vast star-forming complex of cosmic gas and dust in the constellation of Orion the Hunter, as viewed by ESA's Gaia satellite after its first 14 months of operations. These views are not photographs but were compiled by mapping the total density of stars (left) and the total amount of radiation, or flux (right), detected by Gaia in each pixel.
Various southern hemisphere civilisations identify shapes of creatures from the animal world in the dark lanes crossing the bright background of the Milky Way. Echoing this time-honoured tradition, astronomers have spotted the shape of a cat – or that of a fox – in this cloud, depending on whether the bright spot just right of centre is viewed as a nose or an eye. In fact, the cat's nose (or fox's eye) corresponds to the Orion Nebula Cluster, a young open cluster near M42.
On the left, the image based on the stellar density shows the distribution of all stars in the area, and clearly outlines the silhouette of a dark cloud of gas and dust hiding background stars from view. On the right, the image based on the total flux is dominated by the brightest, most massive stars; in some spots, these stars outshine their less bright, lower-mass counterparts.
This image was produced by André Moitinho, Márcia Barros, Carlos Barata from the University of Lisbon, Portugal, and Hélder Savietto from Fork Research, Portugal. The creation of this and other similar images is described in the paper "Gaia Data Release 1: The archive visualisation service" by A. Moitinho et al. 2017, A&A, 605, A52.