Many new HARPS discoveries?

The post at the Systemic blog, at http://oklo.org/?p=281 says that the orbit of HD 40307 b may have an eccentricity of 0.02. No doubt induced by HD 40307 c. I eagerly await papers.

I wonder how they got such informations having no paper available :?

Edasich wrote:

I wonder how they got such informations having no paper available :?

One of the people who works with Systmeic was at a meeting before Nantes Conference, according to Greg. From that meeting, a few details about the 45 candidates were released. Monday's announcenement of the three planets was a public release, which as you know tends to be significantly less informative than what is actually known.

Updated data for HD 40307 system: added orbital separations. Eccentricities look zero so far.

http://exoplanet.eu/star.php?st=HD+40307

About a year ago on the original forum, Jyril quoted the Dynamics of Cats blogs, writing,

Quote :

There are now 13 known Neptune mass planets, with more candidates in the pipeline (30-50 candidates just in the HARPS data set)!

Looks like what we've been given is a taste of these candidates.

Additionally, that same blog wrote

Quote :

Oh, and OGLE has a new microlensing planet detection - two planets in the same system! Numbers look spectacular, formal paper and announcement should be Real Soon Now.

... which as we know now as OGLE-06-109L, from which information was released this February(ish?) So "real soon now" seems to imply eight months.

Yeah, too much gap between rumours and confirmation at all.

Who knows when 37 solid candidates hosting SuperEarth will be anounced.... -_____-

They will be announced when the discoveries are secure enough. It'll take time: you can bet they're doing good science, not making premature announcements in order to increase the planet tally.

Regarding the "secure enough" issue, if you read the HD 40307 paper you will note that they had a case for a 3-planet system at the end of 2006, but decided to take more measurements: how's that for ensuring that the planetary parameters are good?

If so Gamma Cephei b was inferred in 1986 and Pollux b in 1991 by Hatzes and Cochran, but confirmation came only in 21st century *lol*
There is a substellar companion of undefined mass and orbital separation around Mu Herculis A which's still waiting to be confirmed or disproven since 1999 too

Surely new methods and instruments allow much smaller gap between hypothesis and confirmation.


It's just us (or only me, perhaps) which eagerly wait to see exoplanet list growing more and more...

Lazarus wrote:

Regarding the "secure enough" issue, if you read the HD 40307 paper you will note that they had a case for a 3-planet system at the end of 2006, but decided to take more measurements: how's that for ensuring that the planetary parameters are good?

Indeed, I did read this. Considering all the planets have a period of less than 50 days, taking another two years of radial velocity data will definitely help constrain yuor models.

Edasich wrote:

It's just us (or only me, perhaps) which eagerly wait to see exoplanet list growing more and more...

Actually, I do wish to see the count rise, quite a bit. I must say though that the pain I suffer when a planet is disconfirmed (i.e. HD 34445 b or HD 188753 Ab, or HD 33636 b, or TMR-1c), is far greater than the joy I experience when a new planet is found. (The demotion of HD 34445 b and HD 33636 b was done with HST astrometry which determined their mass to be equivalent to that of an M-dwarf... HD 188753 b was "found" in 2005, but a later search failed to reproduce the results, and TMR-1c was just a rediculous case of the scientists jumped to conclusion. As for Pluto, meh, I was glad when that mess was finally over (sort-of)) So, I am willing to wait longer for more secure planet discoveries, then to have them announced quickly and die off as new data comes in.

But still, "Real Soon Now" shouldn't equal 8 months, lol.

Edasich wrote:

Who knows when 37 solid candidates hosting SuperEarth will be anounced....

Actually, they're low-mass planets, being non-Jovian. Some of those planets are surely Neptune-mass. I like that they also included any detected Jovian planets in their announcement. Which means that when all of the candidates are finally released, we'll have more than just those, but rather, several extra Jovian planets along with them. So, think of that number as a minimum amount of planets, but don't think of that number as the amount of detected superEarths.

Also, another thing I wish to point out, among the three systems, HD 47186 has no known Super-Earths. The low-mass planet is a Neptune-mass object. So the June 16 announcement describes only four superEarths. It seems there's a lot of "5 new superEarths" talk (i,e, Extrasolar Planets Encyclopaedia main page announcements).

5 New SuperEarths?

Edasich wrote:

5 New SuperEarths?

That's what it says on the EPE main page. When in actuality, four were found.

Sirius_Alpha wrote:

The demotion of HD 34445 b and HD 33636 b was done with HST astrometry which determined their mass to be equivalent to that of an M-dwarf...

Have you got a reference/link for the astrometric detection of HD 34445b?

No, I can't seem to find one. Perhaps I got HD 34445 and HD 33636 cross-confused in my head when I was writing down notes a year or so ago.

In that case, why was it unconfirmed? o_O

In fact, I can't find any reference for the discovery of HD 34445b, so...

Lazarus wrote:

In fact, I can't find any reference for the discovery of HD 34445b, so...

Maybe the paper about the discovery was withdrawn by the author. This would explain the planets condemnation.

Sirius_Alpha wrote:

Edasich wrote:

5 New SuperEarths?

That's what it says on the EPE main page. When in actuality, four were found.

Mmmh, nope, false alarm.

5 Superearths means 3 are around HD 40307 and 2 left around HD 47186 and HD 181433 respectively. So here the 5 SuperEarths....

Edasich wrote:

5 Superearths means 3 are around HD 40307 and 2 left around HD 47186 and HD 181433 respectively. So here the 5 SuperEarths....

The low-mass planet around HD 47186 is about 23 Earth masses, which puts it in the Neptunian mass domain, which is why Sirius_Alpha is claiming it isn't a super-Earth. Whether this planet is an overgrown super-Earth or a Neptune-analogue is the relevant question, especially considering the close distance to the star which may make atmospheric evaporation a major factor in the planet's evolution.

Something interesting. Perhaps a typo, perhaps a new planet. I'm currently in the process of going through the 451 HARPS GTO stars and I got to the star HD 101581. According to the catalogue, the star has a planet (i.e. the "planet" field has a "yes"). HD 101581 is congruent to the star Gliese 435, a K4/5V star 40.7959 light years away. The star does not have any announced companion. Being Gliese 435, I don't know if it's possible for it to have gotten confused with Gliese 436. So, could this be an unannounced planet that we may expect soon? Perhaps the paper was written by these guys, and just hasn't appeared at arXiv or any such site yet?

Looks like your URL got mangled...

Lazarus wrote:

Looks like your URL got mangled...

Sure enough. I've fixed it. Thank-you.

There is also a "yessed" HD 204313. Solar-like star (G5V) at 47.3 pc in Capricornus.

Simbad notes it has a companion detected at 6.22'' south,from 2007. I have not the access to paper (probably a dim M dwarf).

It seems that HD 101581 and HD 204313 are the only two stars in the 451 that have a "yes" but don't have any announced planets.

Hmm. Epsilon Indi A is in the catalogue. Really close at 11.8206 light years, and it has an unconfirmed planet.

YES!!!!!

The HARPS search for southern extra-solar planets. XVII. Super-Earth and Neptune-mass planets in multiple planet systems HD47186 and HD181433
http://arxiv.org/abs/0812.1608

Abstract wrote:

This paper reports on the detection of two new multiple planet systems around solar-like stars HD47186 and HD181433. The first system includes a hot Neptune of 22.78 M_Earth at 4.08-days period and a Saturn of 0.35 M_Jup at 3.7-years period. The second system includes a Super-Earth of 7.5 M_Earth at 9.4-days period, a 0.64 M$_Jup at 2.6-years period as well as a third companion of 0.54 M_Jup with a period of about 6 years. These detections increase to 20 the number of close-in low-mass exoplanets (below 0.1 M_Jup) and strengthen the fact that 80% of these planets are in a multiple planetary systems.

That's right, a third planet at HD 181433!!!
Also, HD 181433 b seems to be quite eccentric, with e = 0.396.