Potential 'terrestrial' planet zone in newly found star systems?

[RogerG]

Given that our solar system has a 5 AU zone (from Jupiter inwards) containing the terrestrial planets, how many other star systems have a similar "empty" (ie not yet found) potential terrestrial zone where such rocky planets might be found?

[NEOWatcher]

Are you thinking of the "habitable zone"?
Given that Pluto is rocky, and used to be a planet, I would think a rocky planet can be just about anywhere.

[WayneFrancis]

Hmmm interesting question. I'd think that the planetary make up of other systems would be dictated by a number of factors to include but not limited to.
1) type of star formed.
2) size of the planetary disk
3) composition of the planetary disk
4) neighbors for the system early in its development.

I'd suspect that while there are some basic ideas that can be applied each system can be radically different if you change any of those parameters.

[TonyE]

Taking the OP literally I had a look at the ExtraSolar Planet database and selected systems where:

There is at least 1 planet detected at >5AU
There are no planets detected inside 5AU

We find that 22 systems meet this criteria, but most of them are a bit strange and may not what you are looking for.

For example:
11 have stellar masses outside the range 0.5 - 2.0 Sol
Only 4 of the systems have eccentricity know for their planets and 2 of those have e~0.4.
Only 5 of the planets have semimajor in the the range 5 - 20. The rest range from 20 to 2500 AU.

[RogerG]

Thanks all for answers. Yes, I appreciate different stellar masses provide very different 'end' effects for planetary formation. Also the higher the metallicity, then 'hot' jupiters seem inevitable at <<1 AU, whereas lesser metallicity maybe the answer for iron-cored rocky planets, similar to our own four 'inside' the 5 AU line (the ice-line?), although migration seems to dog silicate/iron planet formation, unless our four are cores of ice/gas giants left after evaporation of gas/ice (seems unlikely?).

I will admit that WayneFrancis's comment on early developement neighbours leaves me wondering. Can you explain, please?
TonyE, do any of the 22 systems seem similar, if only in part, to our solar system?

[WayneFrancis]

Thanks all for answers. Yes, I appreciate different stellar masses provide very different 'end' effects for planetary formation. Also the higher the metallicity, then 'hot' jupiters seem inevitable at <<1 AU, whereas lesser metallicity maybe the answer for iron-cored rocky planets, similar to our own four 'inside' the 5 AU line (the ice-line?), although migration seems to dog silicate/iron planet formation, unless our four are cores of ice/gas giants left after evaporation of gas/ice (seems unlikely?).

I will admit that WayneFrancis's comment on early developement neighbours leaves me wondering. Can you explain, please?
TonyE, do any of the 22 systems seem similar, if only in part, to our solar system?

Solar systems form in "stellar nurseries". These are giant gas clouds that can have anywhere from a few hundred solar masses of material to hundreds of thousands of solar masses. A star isn't expected to form in isolation. It is thought that something would trigger the formation like a supernova or even large stars that causes a bit of a mix up of the cloud. So You'd get stars forming together. This is why most systems are binary or triplet systems. The stars formed very close to other stars that where forming around the same time.

A near by supernova can provide a lot of material into the cloud to influence what type of systems may end up forming.

[TonyE]

TonyE, do any of the 22 systems seem similar, if only in part, to our solar system?

Beta Pic (http://en.wikipedia.org/wiki/Beta_Pictoris) is interesting. It is young, has one identfied planet at ~8AU and plenty of planet-forming dust. Potential Solar System of the future.

OGLE235-MOA53 has some potential with one planet at 8AU detected by microlensing but no info about its eccentricity and the star is low mass. See OGLE (http://ogle.astrouw.edu.pl/)site.


All the rest I would discount as potential solar systems due to:

- Planet is very high mass and out at 50-2500AU
- Star is brown dwarf or white dwarf or cataclismic variable or pulsar.

I think the point is that, for any solar-like system that has been examined, we would have detected (at least some) of the inner planets already.


These are the systems that came through the filter:

1RXS1609
2M J044144
2M1207
AB Pic
beta Pic
CD-35 2722
CHXR 73
CT Cha
DH Tau
DP Leo
Fomalhaut
GQ Lup
GSC 06214-00210
HN Peg
HR 8799
OGLE235-MOA53
Oph 11
PSR B1620-26
Ross 458
SR 12 AB
UScoCTIO 108
WD 0806-661B

[neilzero]

If more advanced than present humans developed on one of these they could likely populate their own solar system, and possibly another that passed briefly within about 1% of a light year. Some survivors of such a close passage are likely, especially if they have a thousand outposts and colonies that prepared for the close passage. At present, more than one light year from Earth appears far future, perhaps never for humans.
In our solar system outposts or small colonies are probable within a century, at the poles of Mercury, moons of Earth, Mars, Jupiter, Saturn, Uranus and Neptune, plus orbiting man made colonies and outposts, but it is doubtful that long term self sufficiency is possible that soon. Tiny asteroid and comet outposts are also probable, but it will take many centuries for any of these to get a light year from Earth, which will make re-supply very costly = the supplies will deteriorate enroute. Neil