Jordan Invitational — Astronomy

Astronomy · Division C · Jordan Invitational · 2025

65 questions · 141 points · 50 min· 3 questions from the original omitted

You will have 50 minutes to complete your exam. At the end of this time period, you must stop working. Partial credit will be awarded, so attempt as many questions as you can! On calculation questions, partial credit will be awarded for work as well.

Teams will be allowed the use of 2 3-inch binders, 2 laptops, or a combination of both. Teams may also use graphing calculators for this test. If using online notes, teams will NOT be allowed to access the internet or any AI-generative tools.

Teams may use the same device for both taking the test and accessing notes. Out of browser time will not be monitored.

Ties will be broken in accordance with the national Science Olympiad rules in this order: ◆ Q26 ◆ Q41 ◆ Q33

Section A: General Theory

Question 1

2 pts

What is the name of the stellar classification system that classifies stars based on their luminosity?

Question 2

2 pts

In which stellar class would you expect to find the strongest Ca II lines?

A. Class BB. Class DC. Class GD. Class K

Question 3

3 pts

What does CMB stand for? What has it been used to study?

Question 4

1 pt

True/False: Iron rain is often used as an indicator to detect brown dwarfs.

TrueFalse

Question 5

1 pt

Approximately at what temperature will a protostar begin to fuse hydrogen in its core?

A. 10^5 KB. 10^6 KC. 10^7 KD. 10^8 K

Question 6

2 pts

Which of the following star types could NOT be a Herbig Ae/Be star?

A. Class AB. Class FC. Class GD. Class K

Question 8

2 pts

What are 2 ways that the formation of a molecular cloud may be sped up?

Question 9

2 pts · select all that apply

Select the types of galaxies where HII regions are found most commonly:

Question 10

2 pts

Which of the following spectral lines is most prevalent in HI regions?

A. 19 cmB. 21 cmC. 23 cmD. 25 cm

Question 11

2 pts

What objects are the source of radiation that cause photoionization in HII regions?

Question 12

3 pts

Which of the following telescopes would be best for observing a Herbig Ae/Be star?

A. ChandraB. WISEC. Very Large ArrayD. Hubble

Question 13

1 pt

In what kind of galaxy[ies] would you be able to observe a Type 1a supernova?

Question 14

2 pts

What is another name for Type 1b and 1c supernovae?

Question 15

4 pts

What is a pulsar? Where does that term come from?

Question 16

1 pt

Which kind of star can trigger a micronova?

A. Luminous blue variableB. Red giantC. Red supergiantD. White dwarf

Question 17

1 pt

True/False: The CE of a binary system does not rotate at the same speed as the binary system itself.

TrueFalse

Question 18

2 pts

In the Infrared spectrum, the light curve of a Type 1b supernova is most similar to the light curve of which other supernovae type?

A. Type 1aB. Type 1cC. Type 1axD. Type 2

Question 19

4 pts

What are the two “behavioral” phases of a binary star system? Briefly describe both.

Question 20

5 pts

What is a FBG? What hypothetical astronomical concept is it thought to be associated with?

Question 21

3 pts

Which requirement for “planet” classification do dwarf planets fail to meet?

Question 22

2 pts

What is the best exoplanet detection method for measuring a planetary radius?

Question 23

1 pt

Which of the following planetary detection methods would you use to look at free-floating exoplanets?

A. Direct imagingB. MicrolensingC. Transit photometryD. Doppler spectroscopy

Question 24

2 pts

Which of the following scenarios would be best for using the direct imaging method to detect exoplanets?

A. Looking for many exoplanets at one timeB. Finding an exoplanet that does not transit its starC. Finding an exoplanet around an extremely luminous starD. Finding an exoplanet with an extremely large orbital radius

Question 25

2 pts

What are 2 other names for a terrestrial planet type?

Question 26

6 pts

If you were to launch a spacecraft into orbit around Earth without provisioning for extra fuel on board, which Lagrangian point(s) would be best suited for this mission and why? What would be an issue with this spacecraft placement?

Question 27

3 pts

What is the basic principle behind electron degeneracy pressure that allows it to counteract the force of gravitational contraction within a star? Briefly explain how it works.

Question 28

2 pts

What keeps neutron stars from collapsing into black holes under a certain mass? What is the critical mass for neutron star collapse called?

Question 29

1 pt

What event will produce a “zombie star”?

Question 30

1 pt

True or False: both terrestrial and gaseous planets have secondary atmospheres.

TrueFalse

Section B: DSOs

FigureFor questions 31a, 31b, 31c, 31d, 31e, 31f

Question 31a

1 pt

What is the name of the planet on the left?

Question 31b

1 pt

What is the planet on the right called?

Question 31c

1 pt

What type of exoplanet is the planet from part (b)?

Question 31d

2 pts

What exoplanet detection method was used to discover the exoplanet from part (b)? What year was it discovered in?

Question 31e

2 pts

What is the most unique feature about this planet? (Hint: why is it called one of the “brightest” planets?)

Question 31f

1 pt

Who is the main astronomer credited with this planet’s discovery?

FigureFor questions 32a, 32b, 32c, 32d, 32e

Question 32a

1 pt

What is the name of the exoplanet that is part of the system shown above?

Question 32b

1 pt

This planet has an eccentricity similar to what well-known object in our solar system?

Question 32c

2 pts

Scientists used Spitzer to observe what about this exoplanet?

Question 32d

3 pts

It is theorized that this planet’s unique orbit is caused by the Kozai Mechanism. What is the Kozai mechanism and what property of this planet’s orbit would support this theory?

Question 32e

1 pt

What program first discovered this planet?

FigureFor questions 33a, 33b, 33c, 33d, 33e

Question 33a

1 pt

What star does this image show?

Question 33b

2 pts

The white star symbol in the image shows the central location of the star. What causes the thermal emissions shown around the central star?

Question 33c

1 pt

This image has several locations marked with letters A, B, C, and D. At which location would you expect the temperature to be highest?

Question 33d

3 pts

In the image, there is an area that shows no emissions (the black region right above the central star). What likely caused this blank area?

Question 33e

1 pt

What is the stellar classification of the central star of this system?

FigureFor questions 34a, 34b, 34c, 34d, 34e

Question 34a

1 pt

What exoplanet is depicted in the image above?

Question 34b

2 pts

This exoplanet has an alternate designation. What is it and where does it come from?

Question 34c

2 pts

In 2015, a survey reported finding multiple compounds in the atmosphere of this exoplanet. However, two of these compounds were disproven. What were they?

Question 34d

2 pts

There has been sodium detected around this exoplanet. What could this mean?

Question 34e

1 pt

How many Jupiter masses is this exoplanet?

FigureFor questions 35a, 35b, 35c, 35d, 35e

Question 35a

2 pts

What is the name of the exoplanet depicted in this image? What star system does it belong to?

Question 35b

4 pts

How many total exoplanets are there in this system? These exoplanet(s) have name(s) from various myths and legends. What are those name(s)?

Question 35c

1 pt

True/False: The existence of an asteroid belt in this system has been disproved due to the volatile nature of the central star.

TrueFalse

Question 35d

2 pts

What type of star is the central star in this system? How did it form?

Question 35e

1 pt

What constellation is this system located in?

Section C: Calculations

PassageFor questions 36–39

Your friend Steve has just discovered a new planet of mass 5.07 * 10^-5 solar masses orbiting the Sun (he’s just that good). Use this information to answer the following questions:

Question 36

2 pts

The mass of the newly discovered planet is closest to the mass of which already-known planet in our solar system?

Question 37

3 pts

While observing a solar transit of this new planet, you determine that the Sun’s intensity dims to 3.86*10^26 watts. Calculate the planet’s diameter in kilometers.

Question 38

4 pts

Calculate the density of the planet in kg/m^3.

Question 39

4 pts

Referring to the previous question and given that Earth’s density is 5514 kg/m^3, would you expect this planet to be terrestrial? If not, what kind of planet would it be? Explain your answer briefly.

PassageFor question 40

Your friend Steve next turns his telescope to extrasolar systems. He observes a system with a central star called Baguette (2.2 solar masses and 1.3 solar radii), which has two exoplanets (Baguette b and Baguette c). For simplicity, we will assume all the Baguettes orbit in the same plane, which is edge-on to Steve and his telescope.

Question 40

4 pts

Assume Baguette c has an orbital period of 420 days and an aphelion distance of 1.6 AU, what is the eccentricity of Baguette c’s orbit?

PassageFor questions 43–44

Question 43

4 pts

What would be the equilibrium temperature in Kelvin for Baguette C, given that Baguette (the star) has a luminosity of 12.5 solar luminosities? Assume Baguette c has an albedo of 0.08.

Question 44

3 pts

A high-powered telescope does some measurements on Baguette c, and it finds that the actual temperature of the planet is higher than what you calculated in the previous question. What is a reason that may cause this discrepancy between your calculation and the actual temperature?

PassageFor questions 45–47

Lastly, Steve decides to take a look at a molecular cloud in a galaxy far, far away.

Question 45

3 pts

Using his telescope, Steve observes this molecular cloud to be 0.03 arcseconds wide. If this cloud is 50 light-years away from Earth (where Steve is located), what is the radius of this cloud in km?

Question 46

3 pts

If the cloud has a density of 0.05 kg/m³, what would be the mass of this cloud in solar masses?

Question 47

4 pts

Let's assume that the cloud is expanding due to outside forces. If its volume is increasing at a rate of 5.6*10¹ m³/s, how fast is its radius changing at the point when the cloud's radius is 10% larger than it was pre-expansion? Express your answer in units of m/s.