Astronomical events seem to be in fashion and thanks to the strenuous efforts of scientists focused on the study of space and our galaxy in particular, truly surprising discoveries have been made. Like the one recently reported by a group of researchers.
The discovery
Recently, researchers from UC Santa Cruz University in California, US, discovered 200 new distant stars called “RR Lyrae Stars” in the Milky Way’s stellar halo.
The farthest star is located on the perimeter of the outer halo of our galaxy and is more than a million light years from our planet, about half the distance between us and our neighboring Andromeda galaxy (located 2.5 million light years away).
The newly discovered stars are considered “standard candles” due to the pulsations they emit and the intensity of their brightness. Thanks to these qualities, astronomers were able to determine the outer limits of the galaxy’s halo.
To help you better understand the halos that make up the Milky Way, we share the following image:
Image of the inner and outer halos of the Milky Way. A halo is a spherical cloud of stars surrounding a galaxy. (Image credits: NASA, ESA and A. Feild [STScI])
Professor Raja GuhaTakurta commented that the Milky Way and Andromeda are gigantic and there is barely a space between them. Furthermore, he added that the stellar halo of our galaxy is larger than the disk, which has a diameter of about 100,000 light years.
Our house is located in one of the spiral arms of the disk. At the center of the disk there is a central protuberance, around it there is the halo where the oldest stars of the Milky Way are contained and it extends for thousands of light years around.
The researcher also commented that the halo is the most difficult region to study, since its boundaries are very far away, in addition to the fact that there are very few stars, compared to the regions close to the disk and the protuberance. The halo is made up of dark matter and represents the largest percentage of the galaxy’s mass.
“The halo is the hardest part to study because the outer limits are very far away,” GuhaThakurta said. “Stars are very rare compared to the high stellar densities of the disk and bulge, but the halo is dominated by dark matter and actually contains most of the galaxy’s mass.”
A student of Professor GuhaThakurta, student Yuting Fenga, who conducted this study, presented his findings in two papers at the American Astronomical Society meeting in Seattle in January 2023.
According to data previously calculated by the student Feng, the stellar halo should extend around 300 kiloparsecs, about 1 million light years from the center of the galaxy (scientists measure the distances between galaxies with the unit Kiloparsec, which is equivalent to 3,260 light years) . .
The bright RR Lyrae stars detected by Leng and colleagues were found at distances between 20 and 320 kiloparsecs.
The student added that the variable stars worked as reliable trackers to accurately estimate distances and that the observations made confirmed the theoretical calculations of the size of the halo, this is a very important result.
The published study is based on various observations made with MegaPrime/MegaCam, which is a collaboration between CFHT and CEA/IRFU, at the Canada-France-Hawaii Telescope (CFHT), operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l’Univers del Center National de la Recherche Scientifique (CNRS) de France et de la University de Hawaii.
The original article was published on the official UC Santa Cruz website.
Share the science, share the knowledge.
2024-01-22 01:19:52
#newly #discovered #feature #Milky #baffled #scientific #community #Enséñame #Ciencia