Sunflower Plot of the H-R Diagram

[E.T.]

I just stumbled across this and thought I'd share it here. It's a sunflower plot of an H-R diagram of the Hippocras catalog of star data--All of it! I've never seen the H-R diagram presented in this manner.

I wasn't sure what the red dots were at first, but after looking into it I realized that they're a brush of three star data points. You can click on the data point and see the information pertaining to it. From left to right the red dots represent Sirius, Sol, and Proxima Centauri. (attached image: H-R#1.jpg)

After a little poking around I realized that the previous plot was "magnified", representing only 117,631 records. I wanted to see what the H-R plot would look like zoomed out to include the full data set (119,617 records) and this was also interesting. (attached image: H-R#2.jpg)

Thoughts? Anyone care to speculate?

[admin]

thanks for sharing welcome to the site!

[BobDob]

Hello E.T., welcome to Astronomy Forum! Wish I had an intelligent comment on your post, but its beyond me...mebbee more coffee will help.

LLAP!

Bob

[E.T.]

Well it was just something I hadn't seen before. Came across it while looking at a data visualization app. It's from one of the sample "cubes" (self-contained cross-indexed data samples).

[WWPierre]

Pierre mutters, "Florida is way outta scale, and Cuba is in the wrong place." as his eyes glaze over.

He would be interested in an explanation, though.

[NOUN008]

The H&R Diagram gives much information. Describe some of the relationships and correlations, expressed and implied, that can be derived from this graph. What mass & size rules apply to the main sequence?

[The Curmudgeon]

The HR Diagram is a function that (using the units of this sunflower graph) maps color index (temperature) into absolute magnitude. If these quantities are known for a star, then that star’s position in the HR Diagram is determined. If additional information is known for the star, such as its mass and size, then you can record this and, after accumulating these records for many stars, arrive at conclusions about where stars of specific mass, size, temperature and brightness tend to be found in the HR Diagram.

The HR Diagram itself tells you nothing about the mass or size of a star. You assume things about the mass and size (and age) of a star based on its location in the HR Diagram because of the enormous amount of data that has been laboriously accumulated during the past century by thousands of astronomers.

This sunflower graph shows the variation in the density of the star positions in the HR Diagram when the number of stars in the sample becomes very large. This can be useful information, but nothing else can be derived from this graph.

---The Curmudgeon

[The Curmudgeon]

The HR Diagram is a function that (using the units of this sunflower graph) maps color index (temperature) into absolute magnitude. If these quantities are known for a star, then that star’s position in the HR Diagram is determined. If additional information is known for the star, such as its mass and size, then you can record this and, after accumulating these records for many stars, arrive at conclusions about where stars of specific mass, size, temperature and brightness tend to be found in the HR Diagram.

The HR Diagram itself tells you nothing about the mass or size of a star. You assume things about the mass and size (and age) of a star based on its location in the HR Diagram because of the enormous amount of data that has been laboriously accumulated during the past century by thousands of astronomers.

This sunflower graph shows the variation in the density of the star positions in the HR Diagram when the number of stars in the sample becomes very large. This can be useful information, but nothing else can be derived from this graph.

---The Curmudgeon