Observations of the Small Magellanic Cloud revealed something unexpected about this satellite of the Milky Way. In the galaxy closest to us, stars and gas do not rotate synchronously. This means that it is vactically falling apart.
Interaction of the Large and Small Magellanic Clouds
A team led by Satoya Nakano and Kengo Tachihara from Nagoya University in Japan has discovered new insights into the motion of massive stars in the Small Magellanic Cloud, a small galaxy bordering the Milky Way.
Their findings suggest that the gravitational force of the Large Magellanic Cloud, its larger neighbor, may actually be tearing this star system apart. This discovery points to a new pattern in the motion of these stars that could change our understanding of the evolution and interaction of galaxies. The results of the study are published in The Astrophysical Journal Supplement Series.
“When we first got this result, we suspected there might be an error in our method of analysis,” Tachihara said. “However, upon closer examination, the results are indisputable, and we were surprised.”
Movement of stars in a neighboring galaxy
The Small Magellanic Cloud remains one of the closest galaxies to the Milky Way. This proximity allowed the research team to detect and track approximately 7,000 massive stars within the galaxy. These luminaries, which have eight times the mass of our Sun, usually live only a few million years before exploding as supernovae. Their presence indicates regions rich in hydrogen gas, which is a key component of star formation.
“The stars in the SMC were moving in opposite directions on either side of the galaxy, as though they are being pulled apart,” Tachihara said. “Some of these stars are approaching the LMC, while others are moving away from it, suggesting the gravitational influence of the larger galaxy. This unexpected movement supports the hypothesis that the SMC is being disrupted by the LMC, leading to its gradual destruction.”
Another surprising discovery was the lack of rotational motion among massive stars. Unlike our Milky Way, where interstellar gas rotates with the stars, the study revealed a clear pattern. Ordinarily, young massive stars move with the interstellar gas from which they were born because they have not had time to separate from its motion yet. However, the luminaries in the Small Magellanic Cloud do not follow a rotation pattern, indicating that the interstellar gas is also not rotating.
Importance for further research
The study has broader implications for understanding the dynamics of interactions between neighboring galaxies, especially in the early Universe. Astronomers consider the Small Magellanic Cloud an ideal model for studying the origin of the Universe because it shares many features with primordial galaxies, such as low metallicity and weak gravitational potential.
Thus, the researchers’ discoveries about the interaction between the Large and Small Magellanic Clouds may resemble the processes that formed galaxies billions of years ago, providing valuable information about their evolution over cosmic time. The group’s findings may create new insights into these processes.
According to phys.org
