The James Webb Area Telescope not too long ago captured a colorful image of the irregular galaxy NGC 6822. Utilizing its Close to InfraRed Digital camera (NIRCam) and Mid-InfraRed Instrument (MIRI), Webb noticed completely different elements of NGC 6822, together with gas-rich areas and particular natural compounds essential for star and planetary formation.
Though grand, attractive spiral galaxies usually get important consideration, irregular galaxies equivalent to NGC 6822, also referred to as Barnard’s Galaxy, additionally type stars and need to be showcased.
Past the constellation Sagittarius, Barnard’s Galaxy is about 1.5 million light-years from Earth and is a part of the “Native Group” of galaxies. Though on the smaller aspect in galactic phrases, NGC 6822 remains to be about 7,000 light-years throughout.
Whereas not commonly celebrated for its magnificence, NGC 6822 is a well-known goal for house telescopes. Hubble has investigated the area on quite a few events, whereas a world crew utilizing the Subaru telescope recently performed multi-band photometric observations of the galaxy.
Phys.org explains, “NGC 6822 is a wonderful observational goal as its place on the sky is such that it may be noticed from each the northern and the southern hemisphere. Its modest distance permits many multi-band investigations starting from the optical to the near-infrared (NIR) and to the mid-infrared (MIR). Furthermore, its imply metal-intermediate chemical composition and the identification of strong younger, intermediate-age and outdated stellar tracers and its obvious isolation make NGC 6822 a really fascinating laboratory for stellar pulsation and evolution.”
That final sentence is value homing in on. NGC 6822 has low metallicity, which implies that it consists of low proportions of parts aside from hydrogen and helium. Parts past H and He — all different identified parts — are primarily produced by stars all through their lifetimes. This makes NGC 6822 an fascinating area for understanding extra in regards to the nature of the early universe when there was not a lot steel content material current.
The examine of NGC 6822 goes again a very long time, manner earlier than scientists dreamed up house telescopes. The galaxy was first found by its namesake, E.E. Barnard, who wrote about it in 1884. As was usually the case with celestial objects like NGC 6822, Barnard mischaracterized it as an “exceedingly faint nebula.” Over the following few years, extra confusion arose regarding NGC 6822.
Edwin Hubble studied the galaxy in depth and printed an influential paper in 1925.
“N.G.C. 6822, [was] the primary object positively assigned to a area outdoors the galactic system,” Hubble defined. Hubble’s work was very important in increasing humanity’s understanding of the universe. On the time, it was removed from settled science that there even had been objects past the Milky Approach.
Within the Nineteen Sixties, Susan Keyser, the primary girl to obtain a doctorate in astronomy from Caltech, continued Hubble’s work in her thesis. Keyser’s work was probably the most in-depth examine of NGC 6822 till the 2000s.
Immediately, the $10 billion, groundbreaking James Webb Area Telescope continues the work of so many who’ve come earlier than, together with Barnard, Hubble, and Keyser.
Picture credit: ESA/Webb, NASA & CSA, M. Meixner