Golddie-locks Zone and Red Dwarfs

[VedekPako]

What I've realized, is that due to the small habitable zone around a red star, the chances of a world with liquid water around it would be equally small. Due to the size of an A or F class star, they would be mostly likely to host a world with liquid water; however, the shear number of red stars in space, means that most likely, more water worlds orbit a red star than any other type.

[Airbrush]

Most of the stars in our neighborhood are smaller than our Sun. So the habitable zones around nearby stars are smaller than the habitable zone around our Sun.

 

Our Sun is a G-class main sequence star, so nearby are mostly A - F class stars.

Edited March 3, 2010 by Airbrush

[Arch2008]

Most of the stars within like 25 ly are "M" class dwarf stars. IIRC, this is the class of so-called red dwarf stars.

[VedekPako]

I wish there were a way to calculate the odds of an world in the Habitable Zone.

 

Compared to exo systems known are solar system is tranquil and stable. If say, things turned out different and Earth was farther than Mars and Mars was were Earth is, we wouldn't have a habitable system.

[Airbrush]

The conditions here on Earth seem so unlikely that we simply won the cosmic lottery.

[VedekPako]

The conditions here on Earth seem so unlikely that we simply won the cosmic lottery.

 

So, are you suggesting intelligent design? (just kidding).

 

 

I don't think we won a cosmic lottery based on factors such as calculating the odds a world would be in the HZ with the probably masses (too small, Hot Mars; too big, Jupiter(the moons too small to host liquid water and not magnetic field to protect their atmospheres from solar wind, unless Jupiter's can) etc. ) with other factors such as stellar life span.

 

I'm not advocating every system will have an Earth-like world with advanced life. If fact, I think it's just the opposite. Tau Ceti is probably full of Marses and E. Eridandi probably has Venuses, but a world resembling Early Earth and Mars, is at least probable if it's in the HZ and in a system not too old, like Tau Ceti or too young, like E. Eridandi.

[Spyman]

HABITABLE REAL ESTATE AROUND NEARBY STARS

The group was keenly interested in the habitable real estate around red dwarf stars, which are 50-90% smaller than the Sun and much cooler. Although they comprise more than 70% of the Galactic population, they are often overlooked as hosts of planets suitable for life because they shine so feebly. To the group's surprise, although there are only three Sun-like stars of spectral type G and 44 red dwarfs of spectral type M within 5 parsecs (16.4 light years), all the red dwarf habitable real estate added together did not equal the habitable zone of even one Sun like star. It's much like finding that a single large island has more good places to live than several dozen small islands.

http://www.chara.gsu.edu/RECONS/press.2008.01.html

[Mr Skeptic]

Of course. The brighter your star, the further you want to be from it. Since the area of a sphere increases as r^2 and the volume as r^3, increasing r is going to have a big effect.

[Airbrush]

HABITABLE REAL ESTATE AROUND NEARBY STARS

The group was keenly interested in the habitable real estate around red dwarf stars, which are 50-90% smaller than the Sun and much cooler. Although they comprise more than 70% of the Galactic population, they are often overlooked as hosts of planets suitable for life because they shine so feebly. To the group's surprise, although there are only three Sun-like stars of spectral type G and 44 red dwarfs of spectral type M within 5 parsecs (16.4 light years), all the red dwarf habitable real estate added together did not equal the habitable zone of even one Sun like star. It's much like finding that a single large island has more good places to live than several dozen small islands.

http://www.chara.gsu.edu/RECONS/press.2008.01.html

 

Very interesting Spyman, thanks for that. Then we are more alone than I had imagined. If 70% of stars in our entire galaxy are LESS than half the size of our Sun, then that many stars have habitable zones that are proportionately smaller, or non-existant if the star is 90% smaller than our Sun (which I think means stars with only 10% of our Sun's mass).

Edited March 4, 2010 by Airbrush