#AstroMiniBR: How can we know the mass of a galaxy?

Selected interesting astronomical curios produced by TecMundo and #AstroMiniBR collaborators From Twitter profile, is about to share with you some more information about the universe of astronomy last week. See below!

#1: How do you calculate the mass of a galaxy?

Measuring the mass of galaxies is a complex and crucial task for understanding the structure of the universe. A common approach is to use the orbital dynamics of stars within the galaxy itself: By observing the movement of stars relative to the galactic center, astronomers can apply the laws of physics to calculate the total mass.. This method is especially effective in spiral galaxies such as the Milky Way.

Another technique involves making inferences about the total mass of the galaxy by analyzing the rotation rate of interstellar gas clouds. Additionally, the so-called gravitational lens, a consequence of Einstein’s theory of relativity, is used to measure the mass of distant galaxies. Gravitational lensing occurs when light from a distant galaxy is deflected by the gravity of a closer galaxy, providing valuable information about the mass of the nearby galaxy.

Typical values ​​for the mass of galaxies vary considerably, reflecting cosmic diversity. Dwarf galaxies can have masses ranging from millions to several billion solar masses, while spiral galaxies such as the Milky Way generally have masses in the hundreds of billions of solar masses.

Elliptical galaxies, characterized by their more spherical shape, can be even larger, reaching trillions of solar masses. Understanding these audiences is essential deciphering galactic formation and evolution mechanisms and cosmic structures on large scales.

#2: The mystery of the planet that should not exist!

The latest discovery by “planet hunter” astronomers shook the scientific community: A massive exoplanet orbits a star so small it’s unclear how the star could have given birth to it.

The discovery of the planet in question, called LHS 3154b, was published two weeks ago in the journal Science and presents a celestial body between 13 and 17 times the mass of the Earth. But the real mystery is that the host star has only 11% the mass of the Sun.

As planets form from the same disk of starting material near their stars, Leading astrophysical models assume that low-mass stars also tend to form low-mass planets.. And so far observations seemed to bear this out.

Although there have been cases of giant planets hosted by low-mass stars, all those discovered so far are larger than LHS 3154b and orbit at much greater distances from their parent stars. They probably formed differently from the gravitational collapse of clouds of matter.

The team of astronomers who made the discovery believed that LHS 3154b could have formed in a different star system and been ejected to be captured by its current host star; but this would almost certainly result in LHS 3154b’s orbit being highly elliptical rather than circular. there is today.

#3: A cosmic kiss!

Contact binary stars are fascinating star systems that represent a further step in the evolution of binary systems. In these systems, Two stars share a common atmosphere, creating a unique universe configuration.

As these stars orbit each other, their atmospheres overlap and reach a point where physical contact occurs. This extreme proximity creates a mass transfer between stars, fueling a dynamic process involving the constant exchange of stellar material.

Detailed examination of these contact binary stars opinions Important information about the phenomena of mass transfer, stellar evolution and stellar interactions in extreme environments. Moreover, the study of contacting binary stars plays an important role in understanding stellar evolution in multiple systems, expanding our understanding. about the diversity and complexity of the nature of stars.

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