Question 18N.3.HL.TZ0.17
| Date | November 2018 | Marks available | [Maximum mark: 6] | Reference code | 18N.3.HL.TZ0.17 |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Calculate, Describe, Distinguish, State | Question number | 17 | Adapted from | N/A |
A distinctive feature of the constellation Orion is the Trapezium, an open cluster of stars within Orion.
Distinguish between a constellation and an open cluster.
[2]
In cluster, stars are gravitationally bound OR constellation not ✔
In cluster, stars are the same/similar age OR in constellation not ✔
Stars in cluster are close in space/the same distance OR in constellation not ✔
Cluster stars appear closer in night sky than constellation ✔
Clusters originate from same gas cloud OR constellation does not ✔
Mintaka is one of the stars in Orion.
The parallax angle of Mintaka measured from Earth is 3.64 × 10–3 arc-second. Calculate, in parsec, the approximate distance of Mintaka from Earth.
[1]
d = 275 «pc» ✔
State why there is a maximum distance that astronomers can measure using stellar parallax.
[1]
because of the difficulty of measuring very small angles ✔
The Great Nebula is located in Orion. Describe, using the Jeans criterion, the necessary condition for a nebula to form a star.
[2]
mass of gas cloud > Jeans mass ✔
«magnitude of» gravitational potential energy > Ek of particles ✔
cloud collapses/coalesces «to form a protostar» ✔