 # Kellytabares

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## Everything posted by Kellytabares

1. Hi Robin, Oh yes, it does make much more sense now and I can see that the whisps you mentioned have actually some kind of outward movement. Thank you again, so much!!
2. Hi, I am requested to estimate my measurement with a ruler to the nearest 10th of the mm. That's why you see the decimals in my calculations starting from the pulsar. I am doing this the old school way with a ruler, paper and pen instead of calculating the distance with pixels as you've done it which seems well easier. Ignore stars A and B distance. All that is wrong there. Both images' stars should be 219.9mm (in case you ask). And please, excuse my messy work... that is just for calculations, I am submitting a clean and tidy one
3. It does sound crazy, but they both do have the date on the lower right part of the picture to avoid confusion. However, I am growing very suspicious about my knot distances in mm. I did a lot of research today about my equations and absolutely everything seems to be followed step by step and I'm still getting the wrong answers. When you said to re-check my distances for the knots in mm, I did, but still getting the tiny decimal error between images. Or, I am measuring something totally completely different. --- Stars are the bold black dots whilst the knots are the very blurry, hard-to-see, op
4. Hi, Yes, that is exactly the same plates I am using to try to calculate the age. And in fact, it is exactly the same lab work. - I agree that the distance of the knot's motion between the two images is considerably big. I am finding it a little difficult to follow your explanation above about rechecking my calculations of the distance of the knots to the pulsar. I forgot to mentioned that the plate scale for the reference stars A and B in the 1973 image is exactly the same in the 2000 image which is 1.74 "/mm as I mentioned above. My distance for knot one, two, three and four in both
5. Hi, I am trying to use the angular velocity and angular position to find the age of the Crab Nebula but my calculations seem to be erroneous. I am supposed to get a number around 800 but I keep getting 5000+ years of age. I'm going to try to be very specific in what I'm doing to see if there is something in my procedure that is wrong and I'm not noticing. 1) I am given two images from different years with 27 years of difference - 1973 and 2000. I have two reference stars in each image ( A and B ) which both are 385 arc seconds apart. I have to calculate the 'plate scale' for these t
6. Hi Acey, I was wondering, where does the power number 0.4 comes from?
7. Hi Julian. I'm relieved to know it is the right formula. However, I've been told another way which is actually quicker and easier which is Luminosity of the star divided by the Luminosity of the Sun. This way is less tedious But looking at the equation above. I would like to understand it as it still confuses me a little. I have the star being 0.01 Lsun So, plugging the values for Rsun on both sides, that would be: L= 0.01 / 1 Rsun? Which gives me a wrong answer. But if I plug the values in Kilometers: conversion of star radius to kilometers (were 6.96*105 is the solar radius in Km) 0.01 * 6.
8. Hi. I am trying to convert the luminosity of a star into solar units. I have a formula but I am not 100% sure it is the right one: L / Lsun= (R / Rsun)2 . (T / Tsun)4 Does R have to be in solar units? And T of course in Kelvin. Would that give me the luminosity of a star in solar units? Thanks
9. Hi, Sorry I didn't explain the question as I intended to. Basically, we have our sun positioned in the very middle of the sequence due to many factors as Andrew mentions on the above post. So, what can we say about the sun relative to its nearby stars? (in general and not as a objective point of view). For example, relative to the group of stars in the sun's neighbourhood, what could it be say - or inferred - about its luminosity, mass and/or age. Or, why is it believed that the sun is a "normal" kind of star? Or, what would be the future of the sun relative to the nearby stars, would it grow
10. Having in mind that our sun has a yellow colour with a temperature nearly to the 6,000 K - and taking into an account it is located in the middle of the 'Main Sequence' of the HR Diagram - what would be a definition of the sun being relative to the surrounding (nearest) stars?
11. Hi there. When calculating the Flux ratio of two stars they give me the following formula: Everything is good as I jut need to replace the values. However I don't understand why an antilog is needed in both sides plus where the 1/100 come from? I can't seem to get my head around it at all. Find the exercise below. Can I get an explanation from the antilog onwards? So, after that, I go to the test practice and I find this: -Taking into an account the formula from above. Why do I have three values of magnitude for this question? I'm so sorry if what I'm asking is stupid, but I can't really
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