Astronomers discover binary-binary system

Assessment 10 – Solar System


Scientists have discovered the first binary-binary system, meaning that one of the stars in the binary system also has two massive structures of its own in orbit. The two objects are a giant planet 12 times the mass of Jupiter, and a brown dwarf 57 times more massive than Jupiter, according to The objects are 0.1-1.5 AU away from the star, a very small distance, according to This is about the distance from the Earth to our sun, as the graph below from lecture-tutorial Temperature and Formation of Our Solar System shows. In fact, as the researchers say, “For such large companion objects to be stable so close together defies our current popular theories on how solar systems form.”

A correct and specific connection to class lecture-tutorial

As we learned in class, our current understanding of how solar systems form is that  a flat collapsed cloud of gas and debris around a star, called a protoplanetary disk. As time goes on, collisions between particles occur as they move and rotate. Eventually these form planets.

But this new binary-binary system casts some doubts on this model. In HD 87646, the two giant companions are close to the minimum mass for burning deuterium and hydrogen, meaning . According to, The two objects “[H]ave amassed more dust and gas than what a normal  collapsed disk cloud can give.” This means they were probably formed from some different unknown mechanism.

Reflection: “consideration of some subject matter, idea, or purpose”

This conceptual objective allowed me to learn one or more new things. For example, I did not know what a protoplanetary disk is. Now I know that  a protoplanetary disk is a rotating disk of gas and dust that is around a star. This justifies my opinion that I learned at least one thing during this conceptual objective. I consider this objective to have furthered my knowledge and understanding of our solar system and the universe, for that I am thankful. I have come to this determination after careful thought over a period of time.

Author: jakek


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