neptune desert

Hi

I read something on this forum about the "desert of Neptune", a range of forbiden mass  if I remember well, between the ice giants and and the gas giants.

I did not succeed in finding information on the forum. I also searched on ARXIV without results.

Have you some information? Did I dream? Thanks for your future help.

If you type "dessert of Neptune", you're dreaming of a very very big, planet-sized ice cream

Seriously, probably you'd have read this on some HARPS or some other survey Power Point of PDF presentation, talking about the dearth of Neptune-mass planets.

Nevertheless neither I could say exactly where I read this

I think its correct to call "desert sub-saturns"
http://online.kitp.ucsb.edu/online/exoplanets10/udry/oh/21.jpg

i dont understand what the graphic mean... there is not realy a desert. There is a hole too for ~10Me...

See that gap around 30-40 Earth-masses? That's the desert. It isn't a very arid desert, but it is predicted to exist by planet forming models.

Remember that the planets discovered through radial velocity only have minimum masses. Some planets that appear to occupy that desert may be much more massive, but with sin(i) << 1, thus with true masses out of the desert. I.e. The desert may in fact be drier than that graphic shows.

thanks

what is the exact range of mass?

I doubt it's exact. Just, roughly in that area.

Sirius_Alpha wrote:

See that gap around 30-40 Earth-masses?

Yes, 40-50 Earth-masses. For example, current data Encyclopedias. Red for red dwarf, yellow to yellow dwarf.

30-50 for red dwarf stars and 40-50 for yellow dwarf? Or 30-50/40-50 for the two but artifact (M>Msin i)?

Stalker wrote:

30-50 for red dwarf stars and 40-50 for yellow dwarf? Or 30-50/40-50 for the two but artifact (M>Msin i)?

I think red dwarfs in general is a special case. They do not know hot jupiters, with only periods, like Gliese 876bc.
So just specify the location of the desert is difficult. Necessary to accumulate statistics. Let's wait for the publication planets HARSP, COROT'a and Kepler'a.

In the distribution of transiting planets (i.e. known true mass) has seen two of the desert - between the super-earths and neptunes, and between neptunes and saturns. But it was too little data for statistics.