Diameter in AU of a black hole with given mass?

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Homework Help Overview

The problem involves calculating the diameter of a black hole given its mass, specifically a black hole with a mass of approximately 3 x 10^6 solar masses. The context is within astrophysics, focusing on black hole properties and their relationships to mass.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relationship between the mass of the black hole and its diameter, with one participant attempting calculations based on solar mass and distance in astronomical units (AU). Others question whether the problem relates to the Schwarzschild radius.

Discussion Status

The discussion is ongoing, with participants exploring different aspects of the problem. Some guidance has been offered regarding looking up relevant relationships in textbooks or articles, but no consensus has been reached on the approach to take.

Contextual Notes

There is uncertainty regarding the specific equations or relationships needed to connect the mass of the black hole to its diameter, and participants are encouraged to reference external sources for clarification.

PMelol22
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Homework Statement


The Galaxy has a black hole with about 3 x 10^6 M☉. What is its diameter in AU?

Homework Equations


Not sure.

The Attempt at a Solution


3,000,000 solar mass, but not sure how to figure out the diameter in AU. Let's see...diameter of the sun is 1,000,000km

3,000,000 x 1,000,000 = 3 x 10^12 km...one AU is 150 million km...1.5 x 10^8
3x10^12km/1.5x10^8 = 2x10^4 AU??
 
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PMelol22 said:

Homework Statement


The Galaxy has a black hole with about 3 x 10^6 M☉. What is its diameter in AU?

Homework Equations


Not sure.

The Attempt at a Solution


3,000,000 solar mass, but not sure how to figure out the diameter in AU. Let's see...diameter of the sun is 1,000,000km

3,000,000 x 1,000,000 = 3 x 10^12 km...one AU is 150 million km...1.5 x 10^8
3x10^12km/1.5x10^8 = 2x10^4 AU??

Welcome to the PF.

What does your textbook say the relation is between the mass of the BH and its diameter?

Alternately, you can look through the wikipedia article to find that relation... https://en.wikipedia.org/wiki/Black_hole

:smile:
 
I don't see it...
 
Is this question about finding the Schwarzschild radius?
 

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