HD 10180 - 6±1 planets

http://www.obs-hp.fr/ohp2010/submitted_abstracts-100817.pdf

Quote :

Christophe Lovis
Institute: Geneva Observatory
Title: A new low-mass multi-planet system
Abstract:
The HARPS survey of nearby FGK stars has unveiled a new low-mass planetary system
comprising more planets than any other known system. In this talk we will describe the
properties of this system and discuss the implications of this discovery for planet-formation
models. We will also highlight some emerging trends related to the Neptune/super-Earth
population.

Announcing the next week?

I think that probably is 61 Virgo. The second option, that the opening of one additional planet in the 5-planetary system, which was reported a year ago. (link)

https://solar-flux.forumotion.com/extrasolar-news-and-discoveries-f2/corot-results-t9-120.htm#2371

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Tuesday 24
09:50-10:15! Lovis! ! A new low-mass multi-planet system

So announcement on Tuesday, August 24.

How public will this information be made? Will any of us be able to get it?

61 Virgo? Why?

Stalker wrote:

61 Virgo? Why?

One of the most well-studied systems, with great potential for new planets.
https://solar-flux.forumotion.com/extrasolar-news-and-discoveries-f2/two-new-super-earths-61-vir-and-hd1461-t465-15.htm#4391

Quote :

at least 3-4 planets in circular orbits

Interestingly, the conference is dedicated to transit planets. The venue - observatory which the Geneva group has discovery 51 Pegasi b.

What will show us the Geneva group at the 15-year anniversary of the discovery of the first exoplanet in normal stars?

More planets than any other known system... wait a second, eight is the number to beat, no?

Sounds like more demotions are on the way.

Could this be the unannounced M Mayer 5 planet system with an extra? Look forward to seeing what the masses are.

http://exoplanet.eu/star.php?st=HD+10180

7 planets!

The magnificent seven!

see video
http://www.eso.org/public/videos/eso1035a/

What music is better suited to the great discovery?
For example I like - Elton John Believe

Interestingly, once the two planets in the system have a record low K

HD10180g T=602(11) days 21.3 MEarth K=1.55(0.22) m/s
HD10180b T=1.17 days 1.4(0.25) MEarth K=0.82(0.14) m/s (not confirmed)

Wow! Possible eighth habitable planet!

Quote :

From this analysis (Fig. 12), one can see that stable orbits are possible beyond 6 AU (outside the outermost planet’s orbit). More interestingly, stability appears to be also possible around 1 AU, which corresponds to orbital periods within 300 − 350 days, between the orbits of planets f and g, exactly at the habitable zone of HD10180. Among the already known planets, this is the only zone where additional planetary mass companions can survive. With the current HARPS precision of ∼1 ms−1, we estimate that any objectwith a minimummass M > 10 M⊕ would already be visible in the data. Since this does not seem to be the case, if we assume that a planet exists in this stable zone, it should be at most an Earth-sized object.

Gosh. It would sound like quite an exotic system. A orde of Neptune mass worlds and and Earth-sized one in between?

So much for 55 Cancri... at least Sol is still safe.

Hmmm another "smallest planet" claim for something that's still far too massive. And PSR B1257+12 remains the only exoplanetary system that has a configuration looks remotely like our own inner solar system: a bunch of Neptunes within the ice line is definitely not what we've got here. Raises the question of whether any additional planets orbit beyond planet h, they mention they've ruled out Jupiters within 10 AU, but whether any more Neptunes/super-Earths exist would be an interesting question.

(Slightly weird that the least-secure planet is designated b, might be a bit awkward if it turns out to be a false detection. Wouldn't want to end up with two competing nomenclature systems as in the case of Mu Arae, surely?)

Why HD 10180 is listed as a confirmed planet by EPE?

I found this ESO press release statement interesting...

"The newly discovered system of planets around HD 10180 is unique in several respects. First of all, with at least five Neptune-like planets lying within a distance equivalent to the orbit of Mars, this system is more populated than our Solar System in its inner region, and has many more massive planets there. Furthermore, the system probably has no Jupiter-like gas giant. In addition, all the planets seem to have almost circular orbits.

So far, astronomers know of fifteen systems with at least three planets. .
Using the new discovery as well as data for other planetary systems, the astronomers found an equivalent of the Titius–Bode law that exists in our Solar System: the distances of the planets from their star seem to follow a regular pattern. “This could be a signature of the formation process of these planetary systems,” says team member Michel Mayor."

Borislav wrote:

Wow! Possible eighth habitable planet!

Quote :

From this analysis (Fig. 12), one can see that stable orbits are possible beyond 6 AU (outside the outermost planet’s orbit). More interestingly, stability appears to be also possible around 1 AU, which corresponds to orbital periods within 300 − 350 days, between the orbits of planets f and g, exactly at the habitable zone of HD10180. Among the already known planets, this is the only zone where additional planetary mass companions can survive. With the current HARPS precision of ∼1 ms−1, we estimate that any objectwith a minimummass M > 10 M⊕ would already be visible in the data. Since this does not seem to be the case, if we assume that a planet exists in this stable zone, it should be at most an Earth-sized object.

I'm not entirely clear how they conclude that 1 AU is "exactly at the habitable zone" of a star with a luminosity (given in table 1) of 1.49 times solar... that would put a planet at that location closer to the star than several definitions of the habitable zone would allow.

HZ of star HD 10180 is 10-15 % further than sun.I mean HZ is from 0.85 AU with high albedo to 2.0 AU with low albedo,dense atmosphere.Our earth would be so far as 1.15 AU from this star placed in this system

I was thinking about that, too. Considering the equilibrium temperature of Earth is just about at the freezing point of water, I guess the "HZ" would be closer to the star than we would expect based on the location of Earth.

Edit: Changed title.

Make of this what you will.


Pair-correlation analysis of HD 10180 reveals a possible planetary orbit at about 0.92 AU
http://arxiv.org/abs/1009.5507

Quote :

The pair-correlations between the positions of the six known planets in the exoplanetary system HD 10180 are studied. There are six non-trivial and almost equally spaced peaks. This demonstrates longer-ranged positional order between the orbits and suggests a seventh orbit at 0.92 AU that is consistent with these correlations.