habitable zones for star types in miles ?

[JimMarn]

I was working on my site earleir this year and I found, or read a post here, for habitable zones for various star types. I also read some info in The Traveller Book pdf on the FFE cd. This is on pages 28 through 30 in orbit numbers and an exact distance in kilometers from some star.

It gave ranges in millions of miles for each star type, along with the orbit number.

The only info I can find this week is star types and the habitable zones but not the distance from the star.

What I means by ranges are: G zero, 88 - 93 million miles, in Oribit 3; K zero, 86 - 89 million miles, in orbit 2 or 3.

I searched and couldn't fnid it here. I used habitable orbit, planet orbit for the searches.

Did we discuss this ? It wasn't in the thread where I asked about figuring out gravity for a planet based on diameter.

My computer crashed about a week ago, and while I had backups, I apparently didn't have as much backed up as I had thought.

Thanks for any info you can provide on this !

edit:

Apparently I just missed it somehow.

http://www.travellerrpg.com/CotI/Discuss/showthread.php?t=36502

But if you do have additional info, I owuld appreciate it.

edit 2:

I already have the charts in Scouts Book 6, and it doesn't mention the ranges mentioned above.

 

[Timerover51]

Stephen Dole's book, Habitable Planets for Man, gives the habitable zone for F, G, K, and some of the M star classes in Astronomical Units, which you could convert into miles. Are you looking for a specific star type, or basically the whole range?

 

[sudnadja]

Stephen Dole's book, Habitable Planets for Man, gives the habitable zone for F, G, K, and some of the M star classes in Astronomical Units, which you could convert into miles. Are you looking for a specific star type, or basically the whole range?

Habitable Planets for Man is available for free download, incidentally, here.

It should be noted that most of that work is from the 1960s and the definition of habitable zone has been changing fairly significantly since then. The wikipedia article covers some of this in a nutshell. For example, they state that the habitable zone for a high mass, "super earth" planet may extend as much as 3 AU from the Sun, given a possibly significantly stronger greenhouse component for those kinds of works.

 

[LiNeNoiSe]

http://www.planetarybiology.com/calculating_habitable_zone.html

Alternative Method Online Calculator

https://depts.washington.edu/naivpl/content/hz-calculator

 

[LiNeNoiSe]

It should be noted that most of that work is from the 1960s and the definition of habitable zone has been changing fairly significantly since then.

Methods of estimation might have changed. The definition has not. The "habitable zone" is the zone in which liquid water could be present. That doesn't account for fun stuff like albedo, axial tilt, orbital eccentricity, or greenhouse effect. Just because a planet is in the habitable zone doesn't mean it's habitable.

 

[Keklas Rekobah]

First, I’ve made the assumption that the HZ around Sol ranges from 0.707 AU to 1.414 AU (your assumptions may vary, of course). Sol is classed as a G2-V star with a relative luminosity of 1.

Second, I find the luminosity for another class of star. A K5-V star has a relative luminosity of about 0.08 (LBB6p44). This means that the K5-V star’s luminosity is about 8% of Sol’s.

Third, I determine the square root of 0.08 ... which is about 0.28 (refer to the “Inverse-Square Law”).

Finally, multiply 0.707 and 1.414 by 0.28 ... which yields 0.198 and 0.396, respectively.

Thus, the HZ around a K5-V star ranges from about 0.198 AU to 0.396 AU.

The same procedure can be used to determine the “Rock Line” and the “Frost Line” around a star. For Sol, these values are about 0.3 AU and 3.0 AU, respectively.

 

[JimMarn]

Stephen Dole's book, Habitable Planets for Man, gives the habitable zone for F, G, K, and some of the M star classes in Astronomical Units, which you could convert into miles. Are you looking for a specific star type, or basically the whole range?

The whole range of star types, wirth the exception of no super giants. Seems kinda doomed to have a civilization near one.

edit:

Those links don't have the chart I was trying to refind.

 

[JimMarn]

Habitable Planets for Man is available for free download, incidentally, here.

It should be noted that most of that work is from the 1960s and the definition of habitable zone has been changing fairly significantly since then. The wikipedia article covers some of this in a nutshell. For example, they state that the habitable zone for a high mass, "super earth" planet may extend as much as 3 AU from the Sun, given a possibly significantly stronger greenhouse component for those kinds of works.

I downloaded the pdf, I'll look it over.

 

[JimMarn]

My thanks for your help.

Apparently I dreamed the chart. I'll just go with the 'by guess and by golly' distances I came up with. If I did see such a chart, it was apparently in the bookmarks I lost when Win 10 locked up my computer about 2 weeks ago. I got my backup to work, but I'm not sure everything was backedup.

 

[JimMarn]

I downloaded the pdf, I'll look it over.

Pages 84 and 85 has a chart of star types, luminosity, and Ecospheres inner and outer. Other columns to, but this looks like what I can use.

I thought, but didn't know until I read this that star types had a large range.

like K zero to K 9.

 

[Timerover51]

Pages 84 and 85 has a chart of star types, luminosity, and Ecospheres inner and outer. Other columns to, but this looks like what I can use.

I thought, but didn't know until I read this that star types had a large range.

like K zero to K 9.

Remember the following phrase to remember the star types: O,B,A,F,G,K,M.

Oh, Be A Fine Girl, Kiss Me.

 

[aramis]

Range now goes O B A F G K M L T Y.

In the last 15 years, it went from

• O0-O9 B0-B9 A0-A9 F0-F9 G0-G9 K0-K9 M0-M19

to

• O0-O9 B0-B9 A0-A9 F0-F9 G0-G9 K0-K9 M0-M9 L0-L9 T0-T9 Y0-Y2

Note that Y3 and cooler are expected to be superjovians, below the fusion line, and/or protostars that have not finished collapsing to fusion yet, and/or hot circum jovian mass objects. Technically, Jupiter might qualify for (by extending the scale) Y8 or Y9 just from its internal collapse heat which has yet to finish escaping...

Oh, and the R and N types from the 80's have returned... but are now C-R and C-N...
S-types (generally parallel to M types but always giants, and noted for Zirconium...)
W types lack strong Hydrogen lines... and W9 are hotter than O1...

Any game system is going to have simplifications.

 

[aramis]

Methods of estimation might have changed. The definition has not. The "habitable zone" is the zone in which liquid water could be present. That doesn't account for fun stuff like albedo, axial tilt, orbital eccentricity, or greenhouse effect. Just because a planet is in the habitable zone doesn't mean it's habitable.

The definition has had some subtle changes, such as no longer requiring constant liquid water, and not requiring liquid water solely by insolation.

 

[JimMarn]

I have thought of 'older civilizations' using areas that may not seem worth exploring... and put them there, maybe in a Orbit 9 or so, out from a small Nova.

I'm presuming they moved there after the Nova went off.

 

[Maksim-Smelchak]

T5 doesn't define them with measurement terms, it defines them in terms of orbit.

http://wiki.travellerrpg.com/System

It's not super clear. Some fans came up with a variety of good calculations, but ones that were probably overly complicated. Despite having been championed by key members of the advisor group, they were rejected before they hit T5. Probably a good thing.

Fans who want more detail can easily write it in or otherwise add it to their games.

http://wiki.travellerrpg.com/Habitable_Zone

The Hab Zone only applies to conventional life.

Shalom,
Maksim-Smelchak.

 

[JimMarn]

Hmmm, yes. If I wanted some form of crystal life or methane life, that would happen further out from the local star.

A sf story I read many years ago mentioned life that lived in slushy ice. I think it was in methane. According to the story line they moved, and thought, in centuries.

 

[Keklas Rekobah]

(Bumping this thread so as to not have a duplicate topic for such a trivial post...)

Messing around with some equations for Habitable Zones, and I found out something (that I think is) interesting.

A hypothetical O0-I0 very bright hypergiant star would have its "sweet spot" orbit in the habitable zone at some 5840 A.U. in mean radius. This translates into about 10 light-days out, meaning that light from the hypothetical star would take 10 days to reach a planet orbiting in the center of the star's habitable zone (disregarding the UV flux that would almost certainly sterilize the world).

Such a world would make one complete orbit in about 35300 standard (Earth) years.

The minimum orbital radius for a gas giant to form (again, ignoring UV flux) would be about 17500 A.U., or 31 light-days. The orbital period would then be around 183,000 standard (Earth) years.

I wonder if anyone else ever came up with similar values.

 

[Whipsnade]

I wonder if anyone else ever came up with similar values.

Squinting at the back of the envelope, those numbers looks good to me. Better yet, the consequences are absolutely fascinating. Imagine a ~9000 year "season"...

How "wide" would that star's HZ be? One of Poul Anderson's van Rijn stories featured a super-giant with several habitable worlds orbiting it.

Oh, I wouldn't have called your post, it's questions, and the ideas it could spark "trivial"!

 

[sudnadja]

The minimum orbital radius for a gas giant to form (again, ignoring UV flux) would be about 17500 A.U., or 31 light-days. The orbital period would then be around 183,000 standard (Earth) years.

I wonder if anyone else ever came up with similar values.

Under which ruleset and what did you use as luminosity of the host star?

 

[khadaji2002]

Those orbital periods are fascinating. As Whip points out, a 9000-year-long winter brings a whole new dimension to planetary life. Hmmm....I'm going to have to yoink this idea and play with it for my next game.