ROPS: A New Search for Habitable Earths in the Southern Sky

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ROPS: A New Search for Habitable Earths in the Southern Sky

Post by Edasich on 30th April 2012, 4:59 am

I would keep an eye on this survey

ROPS: A New Search for Habitable Earths in the Southern Sky

We present the first results from our Red Optical Planet Survey (ROPS) to search for low mass planets orbiting late type dwarfs (M5.5V - M9V) in their habitable zones (HZ). Our observations, with the red arm of the MIKE spectrograph (0.5 - 0.9 microns) at the 6.5 m Magellan Clay telescope at Las Campanas Observatory indicate that >= 92 per cent of the flux lies beyond 0.7 microns. We use a novel approach that is essentially a hybrid of the simultaneous iodine and ThAr methods for determining precision radial velocities. We apply least squares deconvolution to obtain a single high S/N ratio stellar line for each spectrum and cross correlate against the simultaneously observed telluric line profile, which we derive in the same way. Utilising the 0.62 - 0.90 micron region, we have achieved an r.m.s. precision of 10 m/s for an M5.5V spectral type star with spectral S/N ~160 on 5 minute timescales. By M8V spectral type, a precision of ~30 m/s at S/N = 25 is suggested, although more observations are needed. An assessment of our errors and scatter in the radial velocity points hints at the presence of stellar radial velocity variations. Of our sample of 7 stars, 2 show radial velocity signals at 6-sigma and 10-sigma of the cross correlation uncertainties. If the signals are planetary in origin, our findings are consistent with estimates of Neptune mass planets that predict a frequency of 13 - 27 per cent for early M dwarfs.Our current analysis indicates the we can achieve a sensitivity that is equivalent to the amplitude induced by a 6 M_Earth planet orbiting in the habitable zone. Based on simulations, we estimate that <10 M_Earth habitable zone planets will be detected in a new stellar mass regime, with <=20 epochs of observations.

Interesting things

Although GJ 3128 appears to show significant radial velocity variationsthat are at 10 of the cross-correlation errors, the same ascending RVs of both observation pairs on both nights raises thepossibility of an as yet unidentified one day aliasing effect. The radial velocity points can be fit with a simple sinusoidal curve with a period of P = 0.511 d, an amplitude of K∗ = 209.4 ms−1 and a residual r.m.s. of 1.8 ms−1. A circular (eccentricity, e = 0) planetary orbit of this period and amplitude could be induced bya mp sin i = 3.29 MNep planet in a very close 0.0058 AU orbit (i.e. 8.31 R∗).

And a possible habitable Neptune around nearby Teegarden's Star...

Our most promising candidate for a stellar radial velocity signature is exhibited by SO J025300.5+165258, which shows a rising trend on the first night and a falling trend on the second night. The r.m.s. scatter is at a level of 6.4 of the cross correlation errors. A sinusoidal fit to the data indicates a period of P = 2.06 d with an amplitude of K∗ = 182.7 kms−1 (residual r.m.s. = 0.46 ms−1). A circular planetary orbit would lead to a mass of mp sin i = 4.88 MNep with a = 0.014 AU, falling inside the classical habitable zone. We emphasise that we make no claims for a planet and clearly further observations are required.
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Re: ROPS: A New Search for Habitable Earths in the Southern Sky

Post by Daniel on 30th April 2012, 12:26 pm

It's don't seems so amazing,on the contrary, if this planets turn to be true it's a big deception, It's more massive that Neptune, Teegarden's Star possible planet it's a super-Neptune in HZ,this planet are very unlikely to possess Earth-size/mass moons around them

As we can see if this planets turn to be true,there is not chance to possess life as we know,This worlds would be just big balls of gas waste in the Red dwarf stars HZ

for the statistics isn't good too,this will just show the Neptune-size planets on the HZ it's much more common the Earth-size planets around the M dwarf stars

But anyway this is a preliminary study, this spectrograph isn't powerful enough to detect Earth mass in Red dwarf HZ and was just 7 stars that have been search.

there are many M dwarf stars like Proxima Centauri that already show that don't possess Neptune mass planet in the HZ,there is still plenty room for Earth-mass planet in HZ around Proxima Centauri like in many other red dwarf stars maybe ever the majority of them have earth mass planets in HZ

then let's wait for more data of the search for planets around this fascinating M Dwarf stars

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Re: ROPS: A New Search for Habitable Earths in the Southern Sky

Post by Daniel on 30th April 2012, 1:28 pm

Teegarden's Star it's likely to be a Brown Dwarf:

http://en.wikipedia.org/wiki/Teegarden's_star
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Re: ROPS: A New Search for Habitable Earths in the Southern Sky

Post by Edasich on 30th April 2012, 3:09 pm

Daniel wrote:It's don't seems so amazing,on the contrary, if this planets turn to be true it's a big deception, It's more massive that Neptune, Teegarden's Star possible planet it's a super-Neptune in HZ,this planet are very unlikely to possess Earth-size/mass moons around them

Actually I just meant "habitable" to say "within the habitable zone". Nor a Neptune-mass or super-Neptune planet is likely to be settled by man...

About Earth-sized bodies, there is ever the Trojan planet possibility...

First the planet has to be confirmed, of course.

Daniel wrote:Teegarden's Star it's likely to be a Brown Dwarf:

http://en.wikipedia.org/wiki/Teegarden's_star

More likely at stellar/brown dwarf boundary. I would regard it as an under-massive star rather a true brown dwarf. Sure its physical parameters are yet poorly constrained, as far as I know.
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Re: ROPS: A New Search for Habitable Earths in the Southern Sky

Post by Lazarus on 30th April 2012, 3:21 pm

The prospects for habitable moons in red dwarf systems do not seem particularly good to me: for starters they would be subject to extremely strong stellar tides.

Interesting feasibility demonstration though claims of planets are premature right now (as the authors state). No doubt they'll wind up on Wikipedia though... Rolling Eyes
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Re: ROPS: A New Search for Habitable Earths in the Southern Sky

Post by Daniel on 30th April 2012, 3:50 pm

Edasich wrote:
Daniel wrote:It's don't seems so amazing,on the contrary, if this planets turn to be true it's a big deception, It's more massive that Neptune, Teegarden's Star possible planet it's a super-Neptune in HZ,this planet are very unlikely to possess Earth-size/mass moons around them

Actually I just meant "habitable" to say "within the habitable zone". Nor a Neptune-mass or super-Neptune planet is likely to be settled by man...

About Earth-sized bodies, there is ever the Trojan planet possibility...

First the planet has to be confirmed, of course.


I know what you meant,and for it I've said Neptune mass planet within the habitable zone for me it's such waste of HZ,Because this world are just balls of gas without any chance of we find life as we know and like you've said this worlds is unlikely to be settled by man something for that is not good,would be much more interesting a rock world in the place of this gas giants, would drastically increase chance of life as we know,ever life as we don't know I don't think that gas giants within the HZ would be a best candidates


About Trojan planets this is very interesting idea to point out, I expect that they find one someday,however till now not ever Kepler mission did find one

like you have said first this planet has to be confirmed,of course.I agree,but it's nice to speculate about this worlds not only for this stars but for many other M dwarfs Wink
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Re: ROPS: A New Search for Habitable Earths in the Southern Sky

Post by Edasich on 30th April 2012, 4:37 pm

I know what you meant,and for it I've said Neptune mass planet within the habitable zone for me it's such waste of HZ,Because this world are just balls of gas without any chance of we find life as we know and like you've said this worlds is unlikely to be settled by man something for that is not good,would be much more interesting a rock world in the place of this gas giants, would drastically increase chance of life as we know,ever life as we don't know I don't think that gas giants within the HZ would be a best candidates.


Good statement indeed. Unless we consider it under "astrobiological" point of view. Could extraterrestrial life could be feasible right there?

I don't know. First confirmation, then we'll talk about again Wink
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Re: ROPS: A New Search for Habitable Earths in the Southern Sky

Post by Lazarus on 30th April 2012, 5:26 pm

Daniel wrote:Teegarden's Star it's likely to be a Brown Dwarf:

http://en.wikipedia.org/wiki/Teegarden's_star
It'd be interesting to know where that's coming from. As far as I can tell, the Wikipedia article is using SIMBAD as basis for this, but it is difficult to know why they decided to assign the brown dwarf category. Certainly it has been included in a few papers about ultracool dwarfs (of which many are brown dwarfs, but some are very low mass stars). I'm not aware of any paper that definitively states this object is substellar.
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Re: ROPS: A New Search for Habitable Earths in the Southern Sky

Post by Lazarus on 22nd January 2014, 4:39 pm

Barnes et al. "Precision radial velocities of 15 M5 - M9 dwarfs"
http://arxiv.org/abs/1401.5350

Getting some pretty decent RV precision there, but there are definitely observational challenges to overcome. In particular, late M-dwarfs tend to be relatively fast rotators and have significant starspots.
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