Break in an arm of the Milky Way galaxy
GS Paper - 3 (Science and Technology)
While a lot about the Milky way galaxy remains unknown to us, recently astronomers have been able to discover a break in one of its arms. Astronomers have found ‘a contingent of young stars and star-forming gas clouds’ sticking out of the Sagittarius Arm of the galaxy, according to a new study published in the Astronomy & Astrophysics journal.
- The authors of the study used NASA’s Spitzer Space Telescope before its retirement in January 2020 to study the nearby portion of the Sagittarius Arm.
- In their observation, they found some newborn stars nestled in the gas and dust clouds (called nebulae).
- The structure discovered in the Milky Way galaxy is stretching over some 3,000 light-years and looks like it is protruding out of the Sagittarius Arm of the galaxy.
- It is the first such discovery in the Milky Way galaxy that is seen to have a dramatically different orientation from the other arms.
- The circle in the middle has a pitch angle of zero degrees. Gradually as the spiral becomes more open and bigger, the pitch angle of the arms also increases.
- Most models of the Milky Way suggest that the Sagittarius Arm forms a spiral that has a pitch angle of about 12 degrees, but the structure we examined really stands out at an angle of nearly 60 degrees.