| Proxima Centauri | |
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+8ciceron tommi59 PlutonianEmpire matthew27 Sirius_Alpha Daniel Lazarus Shellface 12 posters |
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Led_Zep SuperJovian
Number of posts : 721 Location : France Registration date : 2011-09-09
| Subject: Re: Proxima Centauri 4th June 2020, 6:02 pm | |
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Led_Zep SuperJovian
Number of posts : 721 Location : France Registration date : 2011-09-09
| Subject: Re: Proxima Centauri 7th June 2020, 4:10 pm | |
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Lazarus dF star
Number of posts : 3337 Registration date : 2008-06-12
| Subject: Re: Proxima Centauri 17th June 2020, 2:10 pm | |
| Updated orbit for Proxima c from Benedict & McArthur, incorporating the imaging detection. Benedict & McArthur (2020), "A Moving Target—Revising the Mass of Proxima Centauri c" https://iopscience.iop.org/article/10.3847/2515-5172/ab9ca9Notably the mass estimate is decreased to 7±1 Earth masses. Previous orbit presumably still applies if the imaging detection was a false positive. (The orbit determination does not appear to be using the Hipparcos+Gaia data used by Kervella et al.) | |
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Led_Zep SuperJovian
Number of posts : 721 Location : France Registration date : 2011-09-09
| Subject: Re: Proxima Centauri 10th February 2021, 6:14 pm | |
| TEASING ! (video) https://twitter.com/espresso_astro/status/1359510829679394817We are at day -1 of #ProximaLIVE. Be prepared for the release of the ESPRESSO data on Proxima along the next weeks. We have prepared a trailer to leave the suspense... Turn on the volume and enjoy #ProximaLIVE! We do not know the outcome of these observations. But we are seeking for additional signals in #Proxima (the two color lines in the RV plot). The new observations aim at telling us if there is something else in our neighbor. We'll know it at the same time as you! #ProximaLIVE | |
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Sirius_Alpha Admin
Number of posts : 4320 Location : Earth Registration date : 2008-04-06
| Subject: Re: Proxima Centauri 10th February 2021, 9:36 pm | |
| That's exciting! _________________ Caps Lock: Cruise control for 'Cool'!
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Led_Zep SuperJovian
Number of posts : 721 Location : France Registration date : 2011-09-09
| Subject: Re: Proxima Centauri 10th February 2021, 10:09 pm | |
| Precedent paper of ESPRESSO :
"...We find some evidence for the presence of a second short-period signal, at 5.15 days with a semi-amplitude of merely 40 cm/s. If caused by a planetary companion, it would correspond to a minimum mass of 0.29 ± 0.08 Me..."
May be the confirmation ? | |
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Edasich dK star
Number of posts : 2285 Location : Tau Ceti g - Mid Latitudes Registration date : 2008-06-02
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Led_Zep SuperJovian
Number of posts : 721 Location : France Registration date : 2011-09-09
| Subject: Re: Proxima Centauri 22nd February 2021, 5:43 am | |
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Led_Zep SuperJovian
Number of posts : 721 Location : France Registration date : 2011-09-09
| Subject: Re: Proxima Centauri 2nd March 2021, 3:29 pm | |
| ESPRESSO Science Team @espresso_astro Tomorrow, Pedro Figueira will talk about Hunting exoplanets with the ESPRESSO pectrograph, at the @IAC youtube channel https://www.youtube.com/watch?v=Ubij6YInPDE&feature=emb_logoFor planets like Earth in HZ of GK stars we must wait 2023 for publication The five days signal is for Proxima Cen | |
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Led_Zep SuperJovian
Number of posts : 721 Location : France Registration date : 2011-09-09
| Subject: Re: Proxima Centauri 17th March 2021, 10:38 am | |
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Sirius_Alpha Admin
Number of posts : 4320 Location : Earth Registration date : 2008-04-06
| Subject: Re: Proxima Centauri 2nd April 2021, 11:55 pm | |
| Apparently a problem has developed where two different orbital periods are being supported by the data (5 days and 1.2 days) -- one being an alias of the other. So they're shifting to a strategy of observing twice per night. The higher-cadence strategy will help confirm or rule out the 1.2-day periodicity and determine which is the true orbit for the d planet. They describe the problem here, with visuals to explain the aliasing thing. https://twitter.com/espresso_astro/status/1372537759089430533 _________________ Caps Lock: Cruise control for 'Cool'!
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Sirius_Alpha Admin
Number of posts : 4320 Location : Earth Registration date : 2008-04-06
| Subject: Re: Proxima Centauri 19th January 2022, 5:00 pm | |
| _________________ Caps Lock: Cruise control for 'Cool'!
Last edited by Sirius_Alpha on 21st January 2022, 7:40 pm; edited 1 time in total | |
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Edasich dK star
Number of posts : 2285 Location : Tau Ceti g - Mid Latitudes Registration date : 2008-06-02
| Subject: Re: Proxima Centauri 20th January 2022, 10:48 am | |
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extrasolar Micrometeorite
Number of posts : 8 Registration date : 2021-06-26
| Subject: Re: Proxima Centauri 20th January 2022, 2:18 pm | |
| These data and the paper are under embargo until the press release en Feb. 10 | |
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Edasich dK star
Number of posts : 2285 Location : Tau Ceti g - Mid Latitudes Registration date : 2008-06-02
| Subject: Re: Proxima Centauri 20th January 2022, 5:32 pm | |
| - extrasolar wrote:
- These data and the paper are under embargo until the press release en Feb. 10
However Extrasolar Planet Encyclopedia has considered it appropriate to anticipate this finding. Actually the case of Proxima d is a confirmation rather than a new discovery. The presence of Proxima d was indeed suspected since 2020. | |
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Daniel SuperEarth
Number of posts : 272 Registration date : 2009-11-14
| Subject: Re: Proxima Centauri 10th February 2022, 4:50 pm | |
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Edasich dK star
Number of posts : 2285 Location : Tau Ceti g - Mid Latitudes Registration date : 2008-06-02
| Subject: Re: Proxima Centauri 11th February 2022, 4:03 am | |
| Now on ArXiv too: A candidate short-period sub-Earth orbiting Proxima Centauri - Quote :
- Proxima Centauri is the closest star to the Sun. This small, low-mass, mid M dwarf is known to host an Earth-mass exoplanet with an orbital period of 11.2 days within the habitable zone, as well as a long-period planet candidate with an orbital period of close to 5 years. We report on the analysis of a large set of observations taken with the ESPRESSO spectrograph at the VLT aimed at a thorough evaluation of the presence of a third low-mass planetary companion, which started emerging during a previous campaign. Radial velocities (RVs) were calculated using both a cross-correlation function (CCF) and a template matching approach. The RV analysis includes a component to model Proxima's activity using a Gaussian process (GP). We use the CCF's full width at half maximum to help constrain the GP, and we study other simultaneous observables as activity indicators in order to assess the nature of any potential RV signals. We detect a signal at 5.12 0.04 days with a semi-amplitude of 39 7 cm/s. The analysis of subsets of the ESPRESSO data, the activity indicators, and chromatic RVs suggest that this signal is not caused by stellar variability but instead by a planetary companion with a minimum mass of 0.26 0.05 (about twice the mass of Mars) orbiting at 0.029 au from the star. The orbital eccentricity is well constrained and compatible with a circular orbit.
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Lazarus dF star
Number of posts : 3337 Registration date : 2008-06-12
| Subject: Re: Proxima Centauri 29th July 2022, 11:57 am | |
| Artigau et al. "Line-by-line velocity measurements, an outlier-resistant method for precision velocimetry" https://arxiv.org/abs/2207.13524v1 - Quote :
- LBL analysis of the Proxima Centauri HARPS post-upgrade data alone easily recovers the Proxima b signal and also provides a 2-sigma detection of the recently confirmed 5-day Proxima d planet, but argues against the presence of the candidate Proxima c with a period of 1900 days. We provide evidence that the Proxima c signal is associated with small, unaccounted systematic effects affecting the HARPS-TERRA template matching RV extraction method for long-period signals.
Not sure if the astrometric data is sufficiently independent of the RV that it still supports the existence of planet c. They also confirm that Barnard b is an artifact caused by a combination of time sampling and activity. | |
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