| Large batch of planet candidates, including Lalande 21185 | |
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Lazarus dF star
Number of posts : 3337 Registration date : 2008-06-12
| Subject: Large batch of planet candidates, including Lalande 21185 13th February 2017, 3:51 pm | |
| News releasePaper: Butler et al. (2017) - pdfDetails of 20-year planet survey by the Lick-Carnegie Exoplanet Survey Team, with 60 significant unpublished candidates, including a hot super-Earth candidate at Lalande 21185 (Gliese 411). They come out in favour of the planet interpretation for the candidate Jupiter-analogue at HD 154345. Seems more follow-up will be necessary to fully secure the planet interpretation of the new candidates. | |
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Sirius_Alpha Admin
Number of posts : 4319 Location : Earth Registration date : 2008-04-06
| Subject: Re: Large batch of planet candidates, including Lalande 21185 13th February 2017, 4:44 pm | |
| Is there a complete list of planets (periods, m sin i, etc) or are they going to make us shove the raw HIRES data into Systemic ourselves ? _________________ Caps Lock: Cruise control for 'Cool'!
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Lazarus dF star
Number of posts : 3337 Registration date : 2008-06-12
| Subject: Re: Large batch of planet candidates, including Lalande 21185 13th February 2017, 6:45 pm | |
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Lazarus dF star
Number of posts : 3337 Registration date : 2008-06-12
| Subject: Re: Large batch of planet candidates, including Lalande 21185 13th February 2017, 7:57 pm | |
| Pity it doesn't mention the astrometric claims for Lalande 21185. Not sure what the dataset has to say about it because Systemic2 is totally unstable for me (I can get it to run but attempting to load a dataset causes an immediate crash). | |
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Led_Zep SuperJovian
Number of posts : 721 Location : France Registration date : 2011-09-09
| Subject: Re: Large batch of planet candidates, including Lalande 21185 14th February 2017, 5:08 am | |
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Edasich dK star
Number of posts : 2267 Location : Tau Ceti g - Mid Latitudes Registration date : 2008-06-02
| Subject: Re: Large batch of planet candidates, including Lalande 21185 14th February 2017, 5:32 am | |
| Listed: http://exoplanet.eu/catalog/lalande_21185_b/The Solar Neighborhood gradually unveiled. I also recall of a pair of "old" papers where a very long period candidate planet for 41 Arae binary system and a "water Neptune" orbiting Sigma Draconis were inferred. Epsilon Indi A should have a planetary companion soon to confirmed too. | |
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Lazarus dF star
Number of posts : 3337 Registration date : 2008-06-12
| Subject: Re: Large batch of planet candidates, including Lalande 21185 17th February 2017, 8:08 pm | |
| Managed to get systemic working, modern stricter gcc did not play nice with a couple of bits of it. (Downloaded version 2.2, then applied these three fixes to get it to compile on Ubuntu 16.10). I can get Lalande 21185 "b" out of the first part of the data, but the full dataset doesn't return it, I think the outliers toward the end of the dataset screw everything up. There doesn't appear to be anything at the 5.8-year period claimed by Gatewood (1996), so unless the orbit is face-on (the inclination doesn't seem to have been published) I guess Lalande 21185 goes into the long list of disproven astrometric planet claims, again (for the earlier claims for this system, see van de Kamp & Lippincott, 1951 and Lippincott, 1960). There is a long period variation at ~4500 days, maybe a magnetic cycle or something of that nature? | |
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Sirius_Alpha Admin
Number of posts : 4319 Location : Earth Registration date : 2008-04-06
| Subject: Re: Large batch of planet candidates, including Lalande 21185 18th February 2019, 10:13 pm | |
| SOPHIE detection of a planet at Lalande 21185: The SOPHIE search for northern extrasolar planets. XIV. A temperate (Teq∼300 K) super-earth around the nearby star Gliese 411 https://arxiv.org/abs/1902.06004 - Quote :
- Periodic radial velocity variations in the nearby M-dwarf star Gl411 are reported, based on measurements with the SOPHIE spectrograph. Current data do not allow us to distinguish between a 12.95-day period and its one-day alias at 1.08 days, but favour the former slightly. The velocity variation has an amplitude of 1.6 m/s, making this the lowest-amplitude signal detected with SOPHIE up to now. We have performed a detailed analysis of the significance of the signal and its origin, including extensive simulations with both uncorrelated and correlated noise, representing the signal induced by stellar activity. The signal is significantly detected, and the results from all tests point to its planetary origin. Additionally, the presence of an additional acceleration in the velocity time series is suggested by the current data. On the other hand, a previously reported signal with a period of 9.9 days, detected in HIRES velocities of this star, is not recovered in the SOPHIE data. An independent analysis of the HIRES dataset also fails to unveil the 9.9-day signal.
If the 12.95-day period is the real one, the amplitude of the signal detected with SOPHIE implies the presence of a planet, called Gl411 b, with a minimum mass of around three Earth masses, orbiting its star at a distance of 0.079 AU. The planet receives about 3.5 times the insolation received by Earth, which implies an equilibrium temperature between 255 K and 350 K, and makes it too hot to be in the habitable zone. At a distance of only 2.5 pc, Gl411 b, is the third closest low-mass planet detected to date. Its proximity to Earth will permit probing its atmosphere with a combination of high-contrast imaging and high-dispersion spectroscopy in the next decade. _________________ Caps Lock: Cruise control for 'Cool'!
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Edasich dK star
Number of posts : 2267 Location : Tau Ceti g - Mid Latitudes Registration date : 2008-06-02
| Subject: Re: Large batch of planet candidates, including Lalande 21185 19th February 2019, 4:10 am | |
| Orbital period changes significantly. I hope this is the definitive solution. | |
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Lazarus dF star
Number of posts : 3337 Registration date : 2008-06-12
| Subject: Re: Large batch of planet candidates, including Lalande 21185 19th February 2019, 4:18 pm | |
| Interesting to see that result, wasn't too convinced by the first claim (though had only played around with Systemic rather than doing a proper statistical analysis). Hopefully this one holds up a bit better.
Plus another nail in the coffin of the astrometric planet(s). | |
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Sirius_Alpha Admin
Number of posts : 4319 Location : Earth Registration date : 2008-04-06
| Subject: Re: Large batch of planet candidates, including Lalande 21185 28th March 2020, 8:28 pm | |
| All the RV signals are now available, with preiods and RV amplitudes. https://iopscience.iop.org/1538-3881/153/5/208/suppdata/ajaa66cat2_mrt.txtPerhaps this has been the case for quite some time, I don't know. Of note, 83 Leo A may have a planet candidate? 18 Sco appears to have a planet candidate needing confirmation. RV systems HD 24040, HD 75898 and HD 188015 have new possible planet candidates. _________________ Caps Lock: Cruise control for 'Cool'!
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Sirius_Alpha Admin
Number of posts : 4319 Location : Earth Registration date : 2008-04-06
| Subject: Re: Large batch of planet candidates, including Lalande 21185 20th July 2021, 11:20 pm | |
| Another paper on Lalande 21185. Confirmation of the Long-Period Planet Orbiting Gliese 411 and the Detection of a New Planet Candidate https://arxiv.org/abs/2107.09087 _________________ Caps Lock: Cruise control for 'Cool'!
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Edasich dK star
Number of posts : 2267 Location : Tau Ceti g - Mid Latitudes Registration date : 2008-06-02
| Subject: Re: Large batch of planet candidates, including Lalande 21185 30th September 2021, 4:54 am | |
| Only apparently offtopic: a dedicated imaging search for planets/brown dwarfs around selected stars of Solar Neighbourhood (among which Lalande 21185, Barnard's Star and Gliese 15/Groombridge 34) and limits to their presence: GTC/CanariCam deep mid-infrared imaging survey of northern stars within 5 pc - Quote :
- In this work we present the results of a direct imaging survey for brown dwarf companions around the nearest stars at the mid-infrared 10 micron range (λc=8.7μm, Δλ=1.1μm) using the CanariCam instrument at the 10.4 m Gran Telescopio Canarias (GTC). We imaged the 25 nearest stellar systems within 5 pc of the Sun at declinations δ>−25∘ (at least half have planets from radial velocity), reaching a mean detection limit of 11.3±0.2 mag (1.5 mJy) in the Si-2 8.7μm band over a range of angular separations from 1 to 10 arcsec. This would have allowed us to uncover substellar companions at projected orbital separations between ∼2 and 50 au, with effective temperatures down to 600 K and masses greater than 30 MJup assuming an average age of 5 Gyr and down to the deuterium-burning mass limit for objects with ages <1 Gyr. From the non-detection of such companions, we determined upper limits on their occurrence rate at depths and orbital separations yet unexplored by deep imaging programs. For the M dwarfs, main components of our sample, we found with a 90% confidence level that less than 20% of these low-mass stars have L and T-type brown dwarf companions with m≳30MJup and Teff≳ 600 K at ∼3.5--35 au projected orbital separations
Interesting notes in the Appendix: aside persisting but yet unconclusive evidence for a planet around 61 Cygni B, a 6600 d periodicity is reported for Barnard's Star (but activity could be responsible of this) and both of the planet candidates around Gliese 15 A are regarded as "confirmed", although the latter outer one is not reported as such in EPE. | |
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| Subject: Re: Large batch of planet candidates, including Lalande 21185 | |
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| Large batch of planet candidates, including Lalande 21185 | |
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