## Astronomy C

sciolyPA
Member
Posts: 13
Joined: February 15th, 2018, 6:29 pm
Division: C
State: PA

### Re: Astronomy C

A star has three times the mass of the sun, what would its schwarzschild radius be? (Also how do you hide your answer behind an answer box and how do you upload math equations to show work?)

Unome
Moderator
Posts: 4040
Joined: January 26th, 2014, 12:48 pm
State: GA
Location: somewhere in the sciolyverse

### Re: Astronomy C

Code: Select all

[hide]visible text|hidden text[/hide]

Code: Select all

$LaTeX code$

Userpage
Chattahoochee High School Class of 2018
Georgia Tech Class of 2022

Opinions expressed on this site are not official; the only place for official rules changes and FAQs is soinc.org.

sciolyPA
Member
Posts: 13
Joined: February 15th, 2018, 6:29 pm
Division: C
State: PA

### Re: Astronomy C

Unome wrote:

Code: Select all

[hide]visible text|hidden text[/hide]

Code: Select all

$LaTeX code$

Looks good and thanks for the help!

Unome
Moderator
Posts: 4040
Joined: January 26th, 2014, 12:48 pm
State: GA
Location: somewhere in the sciolyverse

### Re: Astronomy C

Image
2. Is this image a spectrum, light curve, or radial velocity graph? (meta question to anyone who can answer - what would be a good way to phrase this without listing options?)
3. What orbital phenomenon does this image show?
4. How many times brighter is the star at peak brightness than at minimum?
Userpage
Chattahoochee High School Class of 2018
Georgia Tech Class of 2022

Opinions expressed on this site are not official; the only place for official rules changes and FAQs is soinc.org.

PM2017
Member
Posts: 483
Joined: January 20th, 2017, 5:02 pm
State: CA

### Re: Astronomy C

Unome wrote:Image
2. Is this image a spectrum, light curve, or radial velocity graph? (meta question to anyone who can answer - what would be a good way to phrase this without listing options?)
3. What orbital phenomenon does this image show?
4. How many times brighter is the star at peak brightness than at minimum?

an answer to your meta question: You could ask, "What type of chart is shown in this image?"

(also, the sad feel when you can answer all the questions except for the first, and probably easiest one... I'm actually clueless as to which DSO this is...)
2018 Events

2019 Events

--
West High '19
UC Berkeley '23

sciolyPA
Member
Posts: 13
Joined: February 15th, 2018, 6:29 pm
Division: C
State: PA

### Re: Astronomy C

Unome wrote:Image
2. Is this image a spectrum, light curve, or radial velocity graph? (meta question to anyone who can answer - what would be a good way to phrase this without listing options?)
3. What orbital phenomenon does this image show?
4. How many times brighter is the star at peak brightness than at minimum?

PM2017
Member
Posts: 483
Joined: January 20th, 2017, 5:02 pm
State: CA

### Re: Astronomy C

PM2017 wrote:I'm actually clueless as to which DSO this is...

sciolyPA wrote:
Unome wrote:Image
2. Is this image a spectrum, light curve, or radial velocity graph? (meta question to anyone who can answer - what would be a good way to phrase this without listing options?)
3. What orbital phenomenon does this image show?
4. How many times brighter is the star at peak brightness than at minimum?

I'm actually stupid... HR 5171 A is the only binary of the type that fits with the light curve given this year...
EDIT: Wait, but doesn't the magnitude not match?
2018 Events

2019 Events

--
West High '19
UC Berkeley '23

sciolyPA
Member
Posts: 13
Joined: February 15th, 2018, 6:29 pm
Division: C
State: PA

### Re: Astronomy C

PM2017 wrote:
PM2017 wrote:I'm actually clueless as to which DSO this is...

sciolyPA wrote:
Unome wrote:Image
2. Is this image a spectrum, light curve, or radial velocity graph? (meta question to anyone who can answer - what would be a good way to phrase this without listing options?)
3. What orbital phenomenon does this image show?
4. How many times brighter is the star at peak brightness than at minimum?

I'm actually stupid... HR 5171 A is the only binary of the type that fits with the light curve given this year...
EDIT: Wait, but doesn't the magnitude not match?

At an invitational earlier this year I got the the same graph with the same scale for HR 5171 A, so I hope it's right.

c0c05w311y
Member
Posts: 19
Joined: February 20th, 2017, 7:56 pm
State: PA
Location: Carnegie Mellon University

### Re: Astronomy C

Unome and everyone really, could you please use image hosting site imgbb instead of imgur or something else so that PM2017, Jonboyage, and I (probably others too) can access the images at school? No need to re-post, just for the future. Thanks

sciolyPA
Member
Posts: 13
Joined: February 15th, 2018, 6:29 pm
Division: C
State: PA

### Re: Astronomy C

A pulsar has a mass of 2.5E30 kg and a radius of 3E4 m.
a) What is its rotational inertia?
b) If it's initial period is 1.6 s, what is it's rotational kinematic energy?
c) Given that it has a spin down rate of .0006 s/y, find the rate of kinematic loss of the pulsar.

Moderator
Posts: 465
Joined: December 6th, 2013, 1:56 pm
State: TX
Location: Austin, Texas

### Re: Astronomy C

sciolyPA wrote:A pulsar has a mass of 2.5E30 kg and a radius of 3E4 m.
a) What is its rotational inertia?
b) If it's initial period is 1.6 s, what is it's rotational kinematic energy?
c) Given that it has a spin down rate of .0006 s/y, find the rate of kinematic loss of the pulsar.

University of Texas at Austin '22
Seven Lakes High School '18
Beckendorff Junior High '14

sciolyPA
Member
Posts: 13
Joined: February 15th, 2018, 6:29 pm
Division: C
State: PA

### Re: Astronomy C

sciolyPA wrote:A pulsar has a mass of 2.5E30 kg and a radius of 3E4 m.
a) What is its rotational inertia?
b) If it's initial period is 1.6 s, what is it's rotational kinematic energy?
c) Given that it has a spin down rate of .0006 s/y, find the rate of kinematic loss of the pulsar.

Moderator
Posts: 465
Joined: December 6th, 2013, 1:56 pm
State: TX
Location: Austin, Texas

### Re: Astronomy C

sciolyPA wrote:
sciolyPA wrote:A pulsar has a mass of 2.5E30 kg and a radius of 3E4 m.
a) What is its rotational inertia?
b) If it's initial period is 1.6 s, what is it's rotational kinematic energy?
c) Given that it has a spin down rate of .0006 s/y, find the rate of kinematic loss of the pulsar.

In the image above:

a) What does the green line represent?
b) What does the light blue line represent?
c) What does the dark blue line represent?
d) The red arrows show evolutionary paths for different pulsars that start at the same location but have different braking indices. Put each evolutionary path (top, middle, and bottom) in order of increasing braking index.
e) The x-axis is on a (linear/logarithmic) scale
University of Texas at Austin '22
Seven Lakes High School '18
Beckendorff Junior High '14

Unome
Moderator
Posts: 4040
Joined: January 26th, 2014, 12:48 pm
State: GA
Location: somewhere in the sciolyverse

### Re: Astronomy C

sciolyPA wrote:

In the image above:

a) What does the green line represent?
b) What does the light blue line represent?
c) What does the dark blue line represent?
d) The red arrows show evolutionary paths for different pulsars that start at the same location but have different braking indices. Put each evolutionary path (top, middle, and bottom) in order of increasing braking index.
e) The x-axis is on a (linear/logarithmic) scale

Userpage
Chattahoochee High School Class of 2018
Georgia Tech Class of 2022

Opinions expressed on this site are not official; the only place for official rules changes and FAQs is soinc.org.

c0c05w311y
Member
Posts: 19
Joined: February 20th, 2017, 7:56 pm