Catalogs of Brown Dwarfs

Description: Brown dwarfs are substellar objects that have masses too low to sustain nuclear fusion in their cores. They are often referred to as 'failed stars' because they lack the mass necessary to ignite hydrogen fusion. Brown dwarfs occupy a unique place in the universe, bridging the gap between stars and planets.
Number of Questions: 14
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Tags: astronomy astrophysics brown dwarfs catalogs
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What is the primary method used to detect brown dwarfs?

  1. Direct imaging

  2. Spectroscopy

  3. Photometry

  4. Radio astronomy


Correct Option: C
Explanation:

Brown dwarfs are typically detected through photometry, which involves measuring their brightness at different wavelengths.

Which catalog is considered the most comprehensive compilation of brown dwarfs?

  1. 2MASS

  2. SDSS

  3. WISE

  4. Gaia


Correct Option: C
Explanation:

The Wide-field Infrared Survey Explorer (WISE) mission has produced the most comprehensive catalog of brown dwarfs to date.

What is the approximate temperature range of brown dwarfs?

  1. 100 - 1,000 K

  2. 1,000 - 2,000 K

  3. 2,000 - 3,000 K

  4. 3,000 - 4,000 K


Correct Option: B
Explanation:

Brown dwarfs typically have temperatures ranging from 1,000 to 2,000 Kelvin.

Which spectral class is commonly associated with brown dwarfs?

  1. M

  2. L

  3. T

  4. Y


Correct Option: B
Explanation:

Brown dwarfs are often classified as L, T, or Y dwarfs based on their spectral features.

What is the approximate mass range of brown dwarfs?

  1. 0.01 - 0.08 solar masses

  2. 0.08 - 0.13 solar masses

  3. 0.13 - 0.25 solar masses

  4. 0.25 - 0.5 solar masses


Correct Option: A
Explanation:

Brown dwarfs typically have masses ranging from 0.01 to 0.08 solar masses.

Which of the following is not a characteristic of brown dwarfs?

  1. They emit infrared radiation

  2. They have strong magnetic fields

  3. They can sustain nuclear fusion

  4. They can form planets


Correct Option: C
Explanation:

Brown dwarfs cannot sustain nuclear fusion in their cores due to their low masses.

What is the name of the first brown dwarf to be discovered?

  1. Gliese 229B

  2. Teide 1

  3. WISE 0855-0714

  4. 2MASS J04151954-0935066


Correct Option: A
Explanation:

Gliese 229B was the first brown dwarf to be discovered in 1995.

Which of the following is not a type of brown dwarf?

  1. M dwarf

  2. L dwarf

  3. T dwarf

  4. Y dwarf


Correct Option: A
Explanation:

M dwarfs are not considered brown dwarfs as they are capable of sustaining nuclear fusion.

What is the approximate age of the oldest known brown dwarf?

  1. 100 million years

  2. 1 billion years

  3. 10 billion years

  4. 100 billion years


Correct Option: C
Explanation:

The oldest known brown dwarf is estimated to be around 10 billion years old.

Which of the following is not a method used to study brown dwarfs?

  1. Direct imaging

  2. Spectroscopy

  3. Photometry

  4. X-ray astronomy


Correct Option: D
Explanation:

X-ray astronomy is not commonly used to study brown dwarfs.

What is the name of the closest known brown dwarf to our solar system?

  1. Barnard's Star

  2. Wolf 359

  3. Luhman 16

  4. WISE 0855-0714


Correct Option: C
Explanation:

Luhman 16 is the closest known brown dwarf to our solar system, located approximately 6.5 light-years away.

Which of the following is not a potential outcome for the evolution of a brown dwarf?

  1. Becoming a white dwarf

  2. Becoming a neutron star

  3. Becoming a black hole

  4. Remaining a brown dwarf indefinitely


Correct Option: B
Explanation:

Brown dwarfs cannot become neutron stars due to their low masses.

What is the approximate number of brown dwarfs estimated to exist in our galaxy?

  1. 10 million

  2. 100 million

  3. 1 billion

  4. 10 billion


Correct Option:
Explanation:

It is estimated that there are approximately 100 billion brown dwarfs in our galaxy.

Which of the following is not a potential method for detecting brown dwarfs in the future?

  1. Direct imaging with advanced telescopes

  2. Spectroscopy with high-resolution instruments

  3. Photometry with wide-field surveys

  4. Gravitational microlensing


Correct Option: D
Explanation:

Gravitational microlensing is not a commonly used method for detecting brown dwarfs.

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