P2 Topic 14 Stellar evolution

Question 1

The Messier Catalogue contains over 100 faint, extended objects.
Suggest why there are no comets in the Messier Catalogue.

Answer 1

Any two sensible suggestions, e.g.
Comets are short-lived (1)
Comets do not have fixed celestial co-ordinates
/ move relative to the stars
Messier was searching for comets (1)

Question 2

The object catalogued by Messier as M83 is also known as NGC 224 in a different
catalogue.
(i) State the meaning of the letters NGC.

Answer 2

New General Catalogue

Question 3

Suggest why there are significantly more entries in the latter catalogue than in the
Messier Catalogue.

Answer 3

Compiled later than Messier Catalogue
…so use of more powerful telescopes
Contains southern hemisphere entries

Question 4

Figure 2 shows a student’s sketch of some stars in the constellation Orion.
The student labelled some of the stars with Greek letters (,  etc.)To what do the Greek letters refer?

Answer 4

relative brightness

Question 5

Which astronomer devised this classification scheme?

Answer 5

Johann Bayer

Question 6

The Orion Nebula is both an emission nebula and an absorption nebula.
(i) In which part of our galaxy is the Orion Nebula located?

Answer 6

disc

Question 7

Explain how the Orion Nebula emits radiation.

Answer 7

(Hydrogen) gas is excited / glows

or by UV radiation from young hot stars in the
nebula

Question 8

The Orion Nebula represent a principal stage in the evolution of stars.
State the name of this principal stage in the evolution of stars.

Answer 8

Birth (of stars) (1)

Question 9

A student observed The Pleiades thorough a small telescope and noted that the
nebula had one distinctive colour.
Which colour did the student observe?

Answer 9

blue

Question 10

The Pleiades contains over 200 stars.
Most of the stars are the same type.
Which type of star does The Pleiades contain?

Answer 10

main sequence

Question 11

A student wishes to make some observations of objects in the Messier Catalogue.
The student is unsure which telescope to use.
The student’s teacher is happy to loan him one of school’s 6-inch reflectors.
Alternatively, the student could make use of a robotic telescope such as the 2-metre Liverpool
Telescope operated by the National Schools’ Observatory.
Compare the advantages of using each type of telescope.

Answer 11

Relevant points may include:
 Messier objects are extended objects.
 School’s reflector is good size and more than adequate for observing
extended objects.
 Reflectors need to be set up properly: more difficult than reflectors.
 Student would gain first-hand experience at observing; data obtained
(drawings) are the student’s own.
 Student is in control of when to observe.
 Student can choose location.
 Telescope can be tracked or motor-driven long enough to make
sketches and drawings.
 Robotic telescope has much larger aperture…