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WorksheetsBrown Dwarfs
Total questions: 20
Worksheet time: 7mins
Name
Class
Date
1.
Energy is generated in the cores of stars by fusing ___
a)
hydrogen into helium
b)
helium into hydrogen
c)
hydrogen into lithium
d)
helium into lithium
2.
The expansion created by the heat of fusion is usually balanced by a star's gravity, creating ___
a)
an imbalance
b)
a conversion
c)
an inversion
d)
an equilibrium
3.
In gas giants, like Jupiter, the force of gravity is balanced by ___
a)
the heat of fusion
b)
simple gas pressure
c)
tidal forces
d)
centripetal forces
4.
The minimum mass for fusing hydrogen, and becoming a star, is roughly ___
a)
twice the mass of Jupiter
b)
7 times the mass of Jupiter
c)
75 times the mass of Jupiter
d)
half the mass of the Sun
5.
Stars form from collapsing gas clouds, just like the Sun did ___ years ago
a)
4.6 million
b)
14.6 million
c)
4.6 billion
d)
14.6 billion
6.
Objects with a mass range between the heaviest planets and the lightest stars became known as ___
a)
red gnomes
b)
brown gnomes
c)
red dwarfs
d)
brown dwarfs
7.
Astronomers classify stars, using letters, based on their ___
a)
temperature
b)
size
c)
luminosity
d)
composition
8.
A new cooler class of star, discovered in 1988, was given the letter ___
a)
'O'
b)
'L'
c)
'F'
d)
'M'
9.
Which element is found in low-mass brown-dwarfs, but not in regular stars?
a)
sodium
b)
magnesium
c)
lithium
d)
beryllium
10.
The very first true brown dwarf was found in 1995 among a cluster of stars called ___
a)
the Pleiades
b)
the nine sisters
c)
Hyades
d)
the Beehive Cluster
11.
Which delicate molecule was found in the spectrum of Gliese 229B, the first T dwarf?
a)
carbon monoxide
b)
carbon dioxide
c)
methane
d)
ammonia
12.
Gliese 229B, the first T dwarf, was one of the first targets of a new camera on ___
a)
The Palomar Hale telescope
b)
The Spitzer Space Telescope
c)
The James Webb Space Telescope
d)
The Hubble Space Telescope
13.
Hundreds of brown dwarfs were discovered by NASA's orbiting observatory called the "wide-field ___"
a)
analysis survey plotter
b)
infrared perusal explorer
c)
infrared survey explorer
d)
infrared survey performer
14.
Warm brown dwarfs, that have molecules like methane and water in their atmosphere, probably look ___
a)
lilac
b)
purple
c)
red
d)
magenta
15.
In WISE images, where astronomers map each infrared color to one our eyes can see, brown dwarfs look ___
a)
green
b)
blue
c)
white
d)
red
16.
As brown dwarfs get more massive, they ___
a)
get smaller and denser
b)
get denser, but not bigger
c)
get larger and denser
d)
get bigger, but not denser
17.
Brown dwarfs, more than about 13 times Jupiter's mass, can fuse both lithium and ___
a)
deuterium
b)
tritium
c)
beryllium
d)
boron
18.
Deuterium is an atom that's very similar to hydrogen except it has ___
a)
a proton and a neutron in its nucleus
b)
two neutrons in its nucleus
c)
two protons in its nucleus
d)
two orbiting electrons
19.
Brown dwarfs are not considered true stars because they don't fuse ___
a)
hydrogen
b)
silicon
c)
lithium
d)
beryllium
20.
In 2013, astronomers found a binary pair of brown dwarfs, called Luhman 16, a distance of only ___
a)
0.65 light years away
b)
6.5 light years away
c)
65 light years away
d)
650 light years away
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