tut5.pdf - Name Bryn Spiller-Tisserand Student 58696097 ASTR 311 \u2014 Tutorial 5 Black Holes and Standard Candles 1 Experiment Run the Clock App from the

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Unformatted text preview: Name: Bryn Spiller-Tisserand Student #: 58696097 ASTR 311 — Tutorial 5 Black Holes and Standard Candles 1 Experiment! Run the Clock App from the following URL: This applet lets you search for a black hole. Unfortunately, the black hole is black and you see it against a black sky background. So how can you find it? The idea is to use clocks to probe the space for the black hole. Here, our clocks are just flashing blue lights, that flash once every second. How to use the applet: • Create a new clock by clicking on ”New Clock”. You can have many clocks running at the same time. • Click the mouse button down on any clock and drag (while holding the mouse button down) the clock to a new location. The clock will change colour and flashing rate depending on its distance to the black hole. • When you think you’ve found the black hole, position the mouse cursor over where you think the black hole is, hold down the ”Shift” key on the computer keyboard, and click the mouse button. The screen will change to show you your results. • You can try and see how fast and how few clocks you need to find the black hole. 1. What TWO changes will happen to the clocks as they get near the black hole? They start to blink faster and become more yellow 2. How long did it take you to locate the black hole and with how many clocks? one and 2 minutes 3. How can astronomers find a black hole in space? We can detect them by their gravitational influence and by the hot disc that surrounds them when they suck things in. This heat can been seen with x-rays which allow us to locate the black hole 2 Practice! In this part you are going to learn about how astronomers can use standard candles to estimate the distances of distant galaxies. The following are data collected from certain types of variable stars. Data Set A 0, 2.301 .699, 3.2499 1, 3.5 1.301, 3.75 1.699, 4.51 Period 1 day 5 days 10 days 20 days 50 days Luminosity 200 L 1778 L 3162 L 5623 L 32000 L Data Set B Period 0.1 days 0.2 days 0.35 days 0.7 days 1 day Luminosity 100 L 100 L 100 L 100 L 100 L -1, 2 -0.699, 2 -0.456, 2 -.155,2 0, 2 1. Plot the points on the graph provided 5 log10 (Luminosity/L ) 4 3 2 1 -1 0 log10 (Period/Day) 1 2 2. What type of variable stars correspond to each data set? Data set A is for an intrinsic star and B is for an extrinsic star 3. What relationship between period and luminosity can you deduce for both classes of variable star, represented by the two data sets? For data set B the luminosity is consistent when compared to the period. It doesn't change as the days progress. For data set A luminosity goes up as the period does but at an inconsistent rate 4. Are these types of variable stars cataclysmic or intrinsic? Explain. 3 Think About It! 1. We observe the following stars D, E, F and G to have pulsation periods of 0.4, 0.8, 15 and 35 days respectively. (a) If all of the stars lie at the same distance list then in order of increasing apparent brightness. (b) If all four stars appear to have the same brightness in our sky list them in order of increasing distance from us. 2. Name three other methods astronomers use to measure distances and describe how each of them work. ...
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• Winter '09
• NA
• Stellar classification, White dwarf, main sequence, Globular cluster