The James Webb Space Telescope Early Release Science (ERS) program – first released on 12 July 2022 – has proven to be a treasure trove of scientific finds and breakthroughs.
It’s allowing for many research areas, including the study of Resolved Stellar Populations. ERS 1334.
This refers to large groups that have enough stars within their reach that individual stars can still be seen, but are far enough apart so that telescopes can simultaneously capture many of them. The following is a good example: Wolf-Lundmark-Melotte(WLM), dwarf galaxy located next to the Milky Way.
Kristen McQuinn is an assistant professor in astrophysics at Rutgers University and one of the leading scientists of the Webb ERS Program whose research is focused on RSTs. Recently, She spoke to Natasha PiroA NASA senior communications specialist discusses how the JWST enabled new studies on the WLM.
Webb’s better observations have shown that this galaxy has not interacted with any other galaxies in its past.
McQuinn says this makes it an excellent candidate for astronomers to examine theories about galaxy formation and evolution. These are some highlights from that interview.
WLM
The WLM is approximately 3,000,000 light-years away from Earth. This means it’s very close (astronomically speaking) to the Milky Way. It is also quite isolated, which astronomers conclude means that it has not interacted with any other systems in the past.
Astronomers noticed in nearby dwarf galaxies that they were often entangled with each other, which suggests that they are in the process or merging.
It is therefore more difficult to study them as their population of stars, gas clouds and other phenomena cannot be completely distinguished from ours.
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WLM has another important feature: it is lower in elements heavier than hydrogen or helium. These elements were abundant in the early Universe. The cores of early star population stars were home to elements like iron, oxygen, silicon and carbon. These elements were then dispersed in supernovae.
WLM is an example of this phenomenon. It has witnessed star formation throughout its history. Over time, the force from these explosions has driven these elements out. This is known as “galactic wind” and has been observed in small, low-mass galaxyes.
JWST Images
Webb images now provide the clearest view ever of WLM. The previous images of the dwarf galaxy were taken by the Camera for InfraredArray(IAC) Spitzer Space Telescope (SST).
These images were of a lower resolution than the Webb images. This can be seen in the side by side comparison (shown below).
Webb’s infrared opticals and sophisticated suite of instruments give a more detailed view than is possible with conventional telescopes, which allows individual stars and other features to be distinguished. McQuinn described it as follows:
“We can see individual stars of different sizes, colors, temperatures, ages and stages of evolution. We also see interesting clouds of gas within the galaxy. Foreground stars have Webb’s Diffraction Spikes. Background galaxies are filled with neat features like tidal trails. It’s a stunning image.
The ERS Programme
McQuinn explained that ERS 1334’s main science focus is to use the expertise of Spitzer, Hubble and other space telescopes in order to learn more about the history, formation, and destruction of stars in galaxies.
They will be using Webb’s to perform deep multi-band imaging of three resolved systems of stars within a Megaparsec (3,260 years from Earth). Near-Infrared Camera(NIRCam). Near-Infrared Imaging Spectrograph (NIRISS).
These include the globular Cluster M92The ultra-faint dwarf galaxies Draco II, and star-forming WLM dwarf galactic.
WLM is home to a large number of low-mass stars. Their long lives make them particularly interesting. It also means that some of the stars we see there may have formed in the early Universe.
McQuinn said, “By determining properties of low-mass stars (like the ages), we can gain insight to what was happening in very distant history.”
“It is very complementary to what we know about the early formation galaxies from looking at Systems with high-redshift“, where you can see galaxies as they were when they formed.”
Another goal is to calibrate JWST using the WLM dwarf galaxie to measure brightness of stars. This will allow astronomers test models of stellar evolution in the near-infrared.
McQuinn, along with her colleagues, are also working on non-proprietary software to measure the brightness of resolved stars scanned using the NIRCam. This software will be available to the general public.
Their ESR results will be made public before the Cycle 2 Call For Proposals (27 Jan 2023).
James Webb Space Telescope, which has been in space for less than one year, has already proven to be invaluable. It provides stunning views of space, such as deep field images, very precise observations of galaxies/nebulae, detailed spectra and spectral from extrasolar atmospheres.
Its scientific breakthroughs have already been nothing short. Some truly paradigm-shifting breakthroughs will be made before the 10-year mission ends (which could be extended up to 20).
This article was first published by Universe Today. Learn more Original article.
