IAAC PreFinal Quiz 2026 Questions and Hints **IAAC 2026…
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IAAC PreFinal Quiz 2026 Questions and Hints
**IAAC 2026 Pre-Final Round — Questions I Remember**
Hey everyone! Just finished my exam. I don't remember all the parts exactly but I'll narrate what I do remember to give you all a rough idea. Hope this helps those who haven't taken it yet! Good luck!
# Problem A — Basic (4 points):
This question was related to the Aristarchus method / dichotomy of the Moon. I don't remember all parts exactly but the ones I remember:
**(a)** When Moon is at half phase (dichotomy), what is the angle at the Moon between Earth and Sun?
**(b)** Given the values of d\_Sun and d\_Moon, calculate the angle θ at Earth between the Moon and Sun.
**(c)** In theory the geometry is perfect but in real observations errors occur. Why do small measurement errors in angle θ cause such large errors in the calculated distance ratio d\_Sun/d\_Moon?
# Problem B — Advanced (6 points):
This question was about dwarf planets and their temperature. Again I don't remember all parts but here is what I recall:
**(a)** A dwarf planet orbits the Sun at a certain distance. Using the concept of thermal equilibrium, prove that its surface temperature is given by:
T\_planet = T\_sun × (R\_sun / 2d)\^(1/2) × (1-A)\^(1/4)
Where A is the albedo of the planet.
**(b)** Using the given luminosity of the Sun and distance of the dwarf planet, calculate its surface temperature.
**(c)** At what wavelength does the dwarf planet emit maximum radiation and what region of the electromagnetic spectrum does this correspond to?
# Problem C — Research (8 points):
This section was directly based on the research paper. Questions were very straightforward. Here is what I remember:
**(a)** Which telescopes were used in the FEAST survey and why was each one necessary for this study?
**(b)** Looking at Table 1 in the paper, which galaxy has the largest population of optically visible young star clusters (oYSC)? Give the exact number.
**(c)** The paper defines an emerging timescale τ\_TOT. Using the cluster counts provided, calculate τ\_TOT for the given galaxy.
**(d)** What is stellar feedback? What physical processes does it include and what role does it play in the emergence of star clusters from their natal clouds?
**(e)** Describe the main trend visible in Figure 3. What does it tell us about the relationship between cluster stellar mass and emergence timescale?
**(f)** What do the terms eYSCI, eYSCII and oYSC mean? What observations and emissions distinguish each class from the others?
#space
source
**IAAC 2026 Pre-Final Round — Questions I Remember**
Hey everyone! Just finished my exam. I don't remember all the parts exactly but I'll narrate what I do remember to give you all a rough idea. Hope this helps those who haven't taken it yet! Good luck!
# Problem A — Basic (4 points):
This question was related to the Aristarchus method / dichotomy of the Moon. I don't remember all parts exactly but the ones I remember:
**(a)** When Moon is at half phase (dichotomy), what is the angle at the Moon between Earth and Sun?
**(b)** Given the values of d\_Sun and d\_Moon, calculate the angle θ at Earth between the Moon and Sun.
**(c)** In theory the geometry is perfect but in real observations errors occur. Why do small measurement errors in angle θ cause such large errors in the calculated distance ratio d\_Sun/d\_Moon?
# Problem B — Advanced (6 points):
This question was about dwarf planets and their temperature. Again I don't remember all parts but here is what I recall:
**(a)** A dwarf planet orbits the Sun at a certain distance. Using the concept of thermal equilibrium, prove that its surface temperature is given by:
T\_planet = T\_sun × (R\_sun / 2d)\^(1/2) × (1-A)\^(1/4)
Where A is the albedo of the planet.
**(b)** Using the given luminosity of the Sun and distance of the dwarf planet, calculate its surface temperature.
**(c)** At what wavelength does the dwarf planet emit maximum radiation and what region of the electromagnetic spectrum does this correspond to?
# Problem C — Research (8 points):
This section was directly based on the research paper. Questions were very straightforward. Here is what I remember:
**(a)** Which telescopes were used in the FEAST survey and why was each one necessary for this study?
**(b)** Looking at Table 1 in the paper, which galaxy has the largest population of optically visible young star clusters (oYSC)? Give the exact number.
**(c)** The paper defines an emerging timescale τ\_TOT. Using the cluster counts provided, calculate τ\_TOT for the given galaxy.
**(d)** What is stellar feedback? What physical processes does it include and what role does it play in the emergence of star clusters from their natal clouds?
**(e)** Describe the main trend visible in Figure 3. What does it tell us about the relationship between cluster stellar mass and emergence timescale?
**(f)** What do the terms eYSCI, eYSCII and oYSC mean? What observations and emissions distinguish each class from the others?
#space
source
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