Proxima Centauri

https://edition.cnn.com/2020/06/04/world/proxima-b-proxima-c-exoplanets-scn/index.html

About Proxima b :

"...Lovis is working on a new instrument called RISTRETTO which will be installed at the Very Large Telescope in Chile. It's designed to directly detect light emitted by the planet, which will allow researchers to characterize the planet's atmosphere and its surface composition..."

About Proxima c :

https://medium.com/amazing-science/proxima-centauri-and-its-two-planets-4ef53a0e728b

Proxima Centauri and Its Two Planets

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/ab9ca9

Notably 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.)

TEASING ! (video)


https://twitter.com/espresso_astro/status/1359510829679394817

We 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

That's exciting!

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 ?

Led_Zep wrote:

TEASING ! (video)


https://twitter.com/espresso_astro/status/1359510829679394817

We 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

Any update

yes !

https://twitter.com/espresso_astro/status/1363220153882865673

https://twitter.com/espresso_astro/status/1362811170894266370

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_logo








For planets like Earth in HZ of GK stars we must wait 2023 for publication

The five days signal is for Proxima Cen

New messages :

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

Proxima Centauri d has been confirmed.

A candidate short-period sub-Earth orbiting Proxima Centauri
https://www.aanda.org/component/article?access=doi&doi=10.1051/0004-6361/202142337

image removed to respect embargo policy

Here it is!

http://exoplanet.eu/catalog/proxima_d/

Quote :

A candidate short-period sub-Earth orbiting Proxima Centauri
https://www.aanda.org/component/article?access=doi&doi=10.1051/0004-6361/202142337

But the paper link is broken or moved elsewhere, perhaps

These data and the paper are under embargo until the press release en Feb. 10

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.

extrasolar wrote:

These data and the paper are under embargo until the press release en Feb. 10

It’s seems confirmed ESO today published about Proxima Centauri d:

https://www.eso.org/public/usa/news/eso2202/?lang

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.

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.