Astronomy 6

Front 1

X-ray bursters occur in binary star systems. The two types of stars that must be present to make up such an object are

Back 1

a main-sequence or giant star and a neutron star in a mass transfer binary.

Front 2

In a neutron star, the core is

Back 2

made of compressed neutrons in contact with each other.

Front 3

What can we detect from matter that has crossed an event horizon?

Back 3

nothing

Front 4

The densely packed neutrons of a neutron star cannot balance the inward pull of gravity if the total mass is

Back 4

greater than Schwartzschild's limit of 3 solar masses

Front 5

What can you conclude about a Type I supernova?

Back 5

It was originally a low-mass star

Front 6

Which stars in globular clusters are believed to be examples of mergers?

Back 6

Blue stragglers

Front 7

As a spaceship's velocity gets closer to the speed of light with respect to an external observer, that observer will report that

Back 7

its length will decrease and its clock will run more slowly.

Front 8

If light from a distant star passes close to a massive body, the light beam will

Back 8

bend towards the star due to gravity.

Front 9

In the Lighthouse Model,

Back 9

if the beam sweeps across us, we will detect a pulse of radiation.

Front 10

An observer on a planet sees a spaceship approaching at 0.5c (where c is the speed of light). A beam of light projected by the ship would be measured by this observer to travel at

Back 10

c.

Front 11

Which is used observationally to determine the age of a star cluster?

Back 11

the luminosity of the main-sequence turn-off point

Front 12

Most pulsars are observed only as ________ sources.

Back 12

radio

Front 13

If the Sun were replaced by a one-solar-mass black hole,

Back 13

we would still orbit it in a period of one year.

Front 14

What would happen if more mass was added to a 1.4-solar-mass neutron star?

Back 14

It would blow off mass as an X-ray burster.

Front 15

Two important properties of young neutron stars are

Back 15

extremely rapid rotation and a strong magnetic field.

Front 16

Which statement about gamma ray bursters is not correct?

Back 16

They are scaled up X-ray bursters, with more massive objects involved.

Front 17

Which are the two most popular candidates for gamma-ray bursters?

Back 17

hypernova making a black hole, and merger of two neutron stars

Front 18

Which of these events is not possible?

Back 18

white dwarfs and companion stars producing recurrent Type I supernova events

Front 19

The mass range for neutron stars is about

Back 19

1 to 3 solar masses.

Front 20

Which of these does not depend on a close binary system to occur?

Back 20

a Type II supernova

Front 21

For a white dwarf to explode entirely as a Type I supernova, its mass must be

Back 21

1.4 solar masses, the Chandrasekhar limit.

Front 22

Pulsars

Back 22

spin very rapidly when they're young.

Front 23

A hypernova creates

Back 23

a black hole.

Front 24

You would expect millisecond pulsars to be

Back 24

part of a binary system.

Front 25

Compared to a cluster containing type O and B stars, a cluster with only type F and cooler stars will be

Back 25

older.

Front 26

Type II supernovae occur when their cores start making

Back 26

iron.

Front 27

A recurrent nova could eventually build up to a

Back 27

Type I supernova.

Front 28

Which statement about black holes is true?

Back 28

Their escape velocity is greater than the speed of light.

Front 29

What explanation does general relativity provide for gravity?

Back 29

Gravity is the result of curved spacetime.