Exploring Starlight

Question 1

What is Apparent Magnitude?

Answer 1

Apparent Magnitude is the brightness of a object in the sky from Earth

Question 2

What is Absolute Magnitude?

Answer 2

Absolute Magnitude is the brightness of a celestial object at 10 parsec

Question 3

Which is brighter? A star with a magnitude of 6 or a star with a magnitude 2?

Answer 3

The star with magnitude of 2 is brighter then the star with a magnitude of 6.

Question 4

How many times brighter is a star with a magnitude of 5 compared to a magnitude of 6?

Answer 4

Magnitude 5 is 2.5x brighter then magnitude 6, each time the magnitude goes up by 1 it is 2.5x brighter

Question 5

What is the distance modulus formula

Answer 5

M = m+5 - (5 log d)

Question 6

What does the distance modulus formula find out?

Answer 6

The distance modulus formula determines the apparent or absolute magnitude of a star

Question 7

What information can be obtained from a stellar spectrum.

Answer 7

Chemical Composition, Temperature, radial velocity, sunspot cycle, wavelength

Question 8

Understand how stars are classified according to the spectral type?

Answer 8

It uses the Morgan Keenan System (O,B,A,F,G,K,M) with M being the coolest of the stars and O being the hottest.

Question 9

How are stars colour and spectral type related to their temperature.

Answer 9

The surface temperature of a star determines the colour light it emits. Blue stars are hotter then yellow stars, which are hotter then red stars

Question 10

How does a stars life cycle relate to the Hertz Sprung Russel Diagram(Those weird clumped up areas of stars diagram)

Answer 10

Stars life cycle relates to the OBAFGKM which determines its position on the HR diagram with M being the longest living and O being the shortest

Question 11

What the inverse square relationship between distance and brightness/intensity.

Answer 11

1/d2 or I/d2

Question 12

How many arc seconds are in a arc minute

Answer 12

60 arc seconds

Question 13

How many arc seconds are in a degree?

Answer 13

3600 arc seconds (60 arc minutes)

Question 14

What is a parsec?

Answer 14

The distance to a star.

Question 15

How to use the Hertz Sprung Russel Diagram to determine the distance to a star

Answer 15

Use Spectroscopic parallax which uses luminosity and temperature which you can use from the HR Diagram

Question 16

What is a binary star?

Answer 16

A binary star is a stellar system consisting of two stars orbiting around their centre of mass.

Question 17

What is a eclipsing binary?

Answer 17

An eclipsing binary is two stars moving in an orbit in line to Earth . That the light at one time can be hidden behind the other like a eclipse.

Question 18

Which of the following are used by astronomers to show how the brightness of a star varies over time.
A. Light Curve
B.Light Graph
C.Light Sabre

Answer 18

A. Light Curve

Question 19

What is a cataclysmic star?

Answer 19

A star which irregularly increases in brightness by a large factor then drop back down

Question 20

What is a Cephied star?

Answer 20

A Cephied variable is a type of star that pulsates radially varying in both diameter and temperature and produces changes in brightness

Question 21

When a star expands does its temperature fall or increase?

Answer 21

When a star expands the temperature falls.

Question 22

Using primary and secondary star, explain the cause of the variability in an eclipsing binary.

Answer 22

The primary and secondary stars are not aligned giving rise to constant brightness. The smaller/secondary dip occurs when the secondary star occurs is behind the primary star.

Question 23

How do you find apparent magnitude using distance modulus formula.

Answer 23

m = M - 5 + (5 log d) (d = parsec)

Question 24

Name one the following are not bound together by gravitation?

Answer 24

Double stars

Question 25

What is a RR Lyrae variable.

Answer 25

RR Lyrae variable stars are periodic variable stars commonly found in global clusters.

Question 26

HR Diagram/Spectroscopic: Which object splits up light from astronomical objects into a spectrum?

Answer 26

Diffraction grating

Question 27

Hertzsprung russell diagram are usually obtained by plotting? etc luminosity to temperature

Answer 27

luminosity against spectral type

Question 28

``` Which star is the hottest? A. B4 B. A9 C. B8 D. A6 ```

Answer 28

A.B4

Question 29

What is the spectral type of the sun

Answer 29

G2

Question 30

Explain the connection line between dark absorption lines and the chemical composition of the stars

Answer 30

Light passing through outer layers of a star is made of all wavelengths/energies; some of this light has the correct wavelength/energy to excite atoms in the stars outer layer When the atoms de-excite They emit radiations/photons of the same wavelengths energy but in a random direction

Question 31

Exploring starlight: How many times does star a appear brighter than star b. Star a = 0.8 Star b = 1.8

Answer 31

2.5x brighter

Question 32

How many times does star B appear brighter than star y Star b = 1.8 Star y = 3.8

Answer 32

6.25x brighter | How to do it: 3.8 - 1.8 = 2.5^2(to the power of 2) = 6.25

Question 33

how many light years are in 1 parsec

Answer 33

3.26 ly

Question 34

In a constellation, star b appears brighter then star e by a factor of 16 The apparent magnitude of e is 3.7; deduce the apparent magnitude of B

Answer 34

square root 16 to the power of 2.5 which rounded is equal to 3 and do 3.7-3 = 0.7 Apparent magnitude of b = 0.7

Question 35

In a constellation, the brightest star a appears 40 times brighter than the faintest star N The apparent magnitude of a is 0.3 deduce the star of magnitude of N

Answer 35

Square root 40 to the power of 2.5 = 4.37

Question 36

At its faintest, A sco is 250x brighter than a globular cluster that lies close to Scorpius Deduce the apparent magnitude of the globular cluster A = 0.9

Answer 36

Square root 250 by 2.5 = 9.1 - 0.9 = 8.2 apparent magnitude

Question 37

What is a astronomical unit

Answer 37

Average distance from the centre of the earth to the distance to the centre of the sun.

Question 38

How do you find distance in parsec.

Answer 38

Distance = 1/parralax angle Parralax angle = 1/distance

Question 39

How many arc seconds and arc minutes are in half a degree.(0.5)

Answer 39

1800 seconds are in half a degree which is 30 arc minutes in a degree

Question 40

A star has a parallax angle of 0.25 degrees how far away is the star.

Answer 40

distance = 1/parallax angle = 1/0.25 = 4 parsec

Question 41

Which types of telescopes can be located at sea level? A. infra red and optical telescopes B. optical and radio telescopes C. Radio and gamma-ray telescopes D. X-ray and optical telescopes

Answer 41

B. optical and radio telescopes

Question 42

Which two types of electromagnetic radiation are not blocked by the Earths Atmosphere

Answer 42

Visible light and radio waves do not get blocked

Question 43

To determine the structure and rotation of our Galaxy (the Milky Way), astronomers often use electromagnetic radiation with a wavelength of 21 cm. In which region of the electromagnetic spectrum does this radiation lie?

Answer 43

Radio Waves

Question 44

The ratio of the diameters of objective elements for a radio telescope and an optical telescope is 6000:1. The corresponding ratio of wavelengths is 360000:1 Determine the ratio: resolution of optical telescope / resolution of radio telescope

Answer 44

360000/6000 = 60 or 1/60 if inverse square law