NuclearVacuum's work

NuclearVacuum wrote:I just watched the "Alien Earths" special on National Geographic, and one of the planets shown was 51 Peg b. I saw it, and I was inspired to do this.

Oww you are lucky to have this channel. This remembers me that I saw another special about the same planet (one of the very rare specials about extrasolar planets) a few years ago (maybe in 2004 or 2005), in that special a probe was sent into the atmosphere. There was a lot of lightning. Shortly after the probe deployed the chutes, it began to melt due to the heat and then a lightning hit the probe...
Maybe you've seen the same special.

Sedna wrote:

NuclearVacuum wrote:I just watched the "Alien Earths" special on National Geographic, and one of the planets shown was 51 Peg b. I saw it, and I was inspired to do this.

Oww you are lucky to have this channel. This remembers me that I saw another special about the same planet (one of the very rare specials about extrasolar planets) a few years ago (maybe in 2004 or 2005), in that special a probe was sent into the atmosphere. There was a lot of lightning. Shortly after the probe deployed the chutes, it began to melt due to the heat and then a lightning hit the probe...
Maybe you've seen the same special.

OMG!! I saw that. So cools!!

Now we are two. It's wierd but I remember this special as I saw it yesterday.

I think that planets as Osiris carry a spectral class as stars and brown dwarfs but with "p" behind (Mp, Lp, Tp, Yp...)

There is no current classification scheme based on planet spectra, just theoretical models of their cloud chemistry (Sudarsky).

I still can't believe that Edasich bead me to the first pic of Gliese 667 Cb. But anyway, here is my version.

A nice Earth-like world eh? I think Gliese 667 Cb's chances for habitability are probably less than that of Gliese 581 c's.

Sirius_Alpha wrote:A nice Earth-like world eh? I think Gliese 667 Cb's chances for habitability are probably less than that of Gliese 581 c's.

Really? I think it seems pretty habitable, but than again, there isn't a lot of data out on the planet as of yet.

Using the SolStation parameters for the star, I get orbital separation of 0.05 AU for a 7 day orbit, and using the SolStation visible luminosity of 0.003 times solar, this is the visible light habitable zone: the planet receives as much visible light from GJ 667C as Earth does from the Sun.

However red dwarfs radiate mainly in the infrared.

This source quotes an absolute bolometric magnitude of 8.95, which translates to 0.02 times the solar luminosity. This puts the HZ at about 0.14 AU.

GJ 667 Cb therefore receives roughly 8 times the amount of stellar radiation that the Earth does, roughly equivalent to Mercury.

Lazarus wrote:Using the SolStation parameters for the star, I get orbital separation of 0.05 AU for a 7 day orbit, and using the SolStation visible luminosity of 0.003 times solar, this is the visible light habitable zone: the planet receives as much visible light from GJ 667C as Earth does from the Sun.

However red dwarfs radiate mainly in the infrared.

This source quotes an absolute bolometric magnitude of 8.95, which translates to 0.02 times the solar luminosity. This puts the HZ at about 0.14 AU.

GJ 667 Cb therefore receives roughly 8 times the amount of stellar radiation that the Earth does, roughly equivalent to Mercury.

Um... what? You are saying its habitable, right?

He's saying that the planet gets as much radiation as Mercury.

Lazarus wrote:GJ 667 Cb therefore receives roughly 8 times the amount of stellar radiation that the Earth does, roughly equivalent to Mercury.

Unless you consider Mercury habitable...

Well there is a big difference between habitability and radiation. The planet seems to be in the habitable zone, but gets very high amounts of radiation. That is what I got from Lazarus' findings. Sorry for the confusion, but I was wanting to know whether this planet was in the habitable zone, not whether it would be a place for humans.

The fact that the planet is radioactive doesn't surprise me the least. Most scientists believe that Earth-like planets around red dwarf stars will have higher radioactivity than the Earth. I occasionally call such worlds "Chernobyl planets." The name comes from the Chernobyl nuclear accident in the USSR, and from the word itself, which means "the black grass" in Russian (coming from the speculation that plants may be black to absorb the most visible light).

Radiation here doesn't necessarily mean high-energy radiation. The Chernobyl core pumps out nice amounts of lethal gamma rays, yes. Surely we can agree that the Microwave oven uses microwaves to cook food, and that those microwaves are a form of radiation. What do microwaves and gamma rays have in common? They're both electromagnetic waves. The two are at different wavelengths though.

Similarly, all wavelengths of energy count as radiation. Visible light, radio waves, infrared, X-ray, anything on the EM spectrum. Radiation is how energy is transferred in a vacuum, and is mostly responsible for the temperature of Earth. Energy from the sun reaches Earth through radiation.

So when Lazarus says that Gliese 667 Cb receives as much radiation as Mercury, he doesn't necessarily mean gamma rays or microwaves, but visible light and infrared too. The amount of radiation a planet receives determines how hot it is, because radiation is absorbed by the planet and turned into heat.

All that can be said is the radiation a planet receives. Lazarus couldn't have said that the planet has the same temperature as Mercury, because we know nothing about how Gliese 667 Cb deals with the radiation it receives (Despite receiving less radiation, Venus is hotter than Mercury).

So, instead of thinking of radiation as high-energy waves, think of radiation as just energy. The more energy the planet receives, the less likely it is to be habitable.

Yes, I wasn't talking about radioactivity at all. Remember that light is electromagnetic radiation! Don't assume that "radiation" means radioactivity. The reason I didn't call it "light" is that "light" is often interpreted as meaning "visible light", but we need to take into account wavelengths the human eye cannot see as well.

The total luminosity at all wavelengths is termed the bolometric luminosity. This quantifies the total power the star puts out. For Gliese 667 C, this total luminosity is 0.02 times that of the Sun. This is the figure you want to use to calculate the habitable zone.

Humans can only see a small part of the spectrum. Electromagnetic radiation in this part of the spectrum is called visible light. Gliese 667 C puts out only 0.003 times the amount of visible light that the Sun does: this figure is much less than the ratio of total luminosities, so Gliese 667 C must be putting out most of its energy at wavelengths that the human eye cannot see.

Once you take into account the contribution of energy across the entire spectrum, the energy flux at Gliese 667 Cb from Gliese 667 C is eight times the energy flux at Earth's orbit from the Sun. Or to put it another way, if you were to move the planet Gliese 667 Cb to our solar system and have it receive the same amount of energy from the Sun as it currently does from Gliese 667 C, you'd have to put it roughly at the orbit of Mercury. The planet therefore receives too much energy to be in the habitable zone.

Just because we can't see some wavelengths of light, doesn't mean that they don't heat up the planet! This is a problem when estimating the habitable zones of planets around stars hotter or cooler than the Sun: in the case of cool stars, most of the energy is emitted at infrared wavelengths, while hot stars emit most of their energy at ultraviolet wavelengths. In both cases, taking the region where the planet receives the same amount of visible light as Earth does will result in you putting the habitable zone too close to the star.

Edasich wins! *lol*

Seriously, you can still infer a habitable world around GJ 667 C and that would work good