# Barnard's Star : RV monitoring

## Barnard's Star : RV monitoring

Wish it may be confirmed soon.

The UVES M Dwarf Planet Search

In the case of Barnard’s star we find a significant signal with a period of 44.9 d and an RV amplitude of ± 2.9 ms–1 (Zechmeister et al., 2009; Kürster et al. 2003). If this signal could be attributed to an orbiting companion, this object would be a Super-Earth with a minimum mass of 4.7 Me. It would orbit somewhat outside of the habitable zone of Barnard’s star.

Edasich
dM star

Number of posts : 1545
Location : Tau Ceti g - Mid Latitudes
Registration date : 2008-06-02

## Re: Barnard's Star : RV monitoring

However, there are reasons to believe that the signal is produced by the star itself, i.e. by its surface activity and its influence on the convective motions that carry the heat transport from the interior to the outer regions of a low-mass star. When examining the line strength of the Hα line one finds the same 44.9 d periodicity. The Hα line originates in the stellar photosphere as an absorption line, but it has superimposed emission components generated in localised, so called “plage”, regions in the chromosphere, a higher and hotter layer of the stellar atmosphere.

_________________
Caps Lock: Cruise control for 'Cool'!

Sirius_Alpha

Number of posts : 3662
Location : Earth
Registration date : 2008-04-06

## Re: Barnard's Star : RV monitoring

*sigh*

Maybe it's timelt to shift this in "Unconfirmed planets" thread, isn't it?

Edasich
dM star

Number of posts : 1545
Location : Tau Ceti g - Mid Latitudes
Registration date : 2008-06-02

## Re: Barnard's Star : RV monitoring

I think Van de Kamp cursed the star somehow. It's probably the only one within 10 parsecs without any planetary companions.

_________________
Caps Lock: Cruise control for 'Cool'!

Sirius_Alpha

Number of posts : 3662
Location : Earth
Registration date : 2008-04-06

## Re: Barnard's Star : RV monitoring

No super-earths may be good news. It leaves room for a normal sized Earth

ciceron
Planetary Embryo

Number of posts : 84
Age : 48
Location : Spain
Registration date : 2008-04-08

## Re: Barnard's Star : RV monitoring

I think the unconfirmed planets thread would be assigning far too much likelihood to this one

Lazarus
dF star

Number of posts : 2979
Registration date : 2008-06-12

## Re: Barnard's Star : RV monitoring

Precise Doppler Monitoring of Barnard's Star
http://arxiv.org/abs/1208.2273

We present 248 precise Doppler measurements of Barnard's Star (Gl 699), the second nearest star system to Earth, obtained from Lick and Keck Observatories during 25 years between 1987 and 2012. The early precision was 20 \ms{} but was 2 \ms{} during the last 8 years, constituting the most extensive and sensitive search for Doppler signatures of planets around this stellar neighbor. We carefully analyze the 136 Keck radial velocities spanning 8 years by first applying a periodogram analysis to search for nearly circular orbits. We find no significant periodic Doppler signals with amplitudes above $\sim$2 \ms{}, setting firm upper limits on the minimum mass (\msini) of any planets with orbital periods from 0.1 to 1000 days. Using a Monte Carlo analysis for circular orbits, we determine that planetary companions to Barnard's Star with masses above 2 \mearth{} and periods below 10 days would have been detected. Planets with periods up to 2 years and masses above 10 \mearth{} (0.03 \mjup) are also ruled out. A similar analysis allowing for eccentric orbits yields comparable mass limits. The habitable zone of Barnard's Star appears to be devoid of roughly Earth-mass planets or larger, save for face-on orbits. Previous claims of planets around the star by van de Kamp are strongly refuted. The radial velocity of Barnard's Star increases with time at $4.515\pm0.002$ \msy{}, consistent with the predicted geometrical effect, secular acceleration, that exchanges transverse for radial components of velocity.

_________________
Caps Lock: Cruise control for 'Cool'!

Sirius_Alpha

Number of posts : 3662
Location : Earth
Registration date : 2008-04-06

## Re: Barnard's Star : RV monitoring

That's starting to get down to the range where the Kepler-42 planets (which orbit a very similar star to Barnard's Star) would possibly be detectable, nice.

Wonder whether the claims for planets around Lalande 21185 will hold up.

Lazarus
dF star

Number of posts : 2979
Registration date : 2008-06-12

## 25 years of doppler analysis of Barnard's star: results and HZ.

Here an interesting paper showing the results of 25 years of spectroscopic observation of Barnard's star.
Interesting results on the HZ also:

http://arxiv.org/abs/1208.2273

Giangore
Micrometeorite

Number of posts : 7
Age : 35
Location : alpha centauri b
Registration date : 2009-10-10

## Re: Barnard's Star : RV monitoring

Giangore wrote:Here an interesting paper showing the results of 25 years of spectroscopic observation of Barnard's star.
Interesting results on the HZ also:

http://arxiv.org/abs/1208.2273
Merged.

_________________
Caps Lock: Cruise control for 'Cool'!

Sirius_Alpha

Number of posts : 3662
Location : Earth
Registration date : 2008-04-06

## Re: Barnard's Star : RV monitoring

That's the day ?

RedDots  ‎@RedDotsSpace
We launch tomorrow at 12.00pm CET! Want to learn more? Follow us! #proxima #reddots #palereddot @Pale_red_dot  #barnardstar #ross154

whoooo.....

Alert Notice 583: Photometry requested for Red Dots campaign

« …"The aim of the Red Dots campaign is to find exoplanets orbiting around three M-Dwarf stars in the solar neighbourhood. This campaign is a follow up to the very successful Pale Red Dot campaign from last year which resulted in the discovery of exoplanet Proxima b. The campaign runs from 19th June to 5th October and the three stars being observed are GJ729 (V1216 Sgr), Proxima Centauri (V645 Cen), and Barnard’s star (V2500 Oph)… »

Led_Zep
Jovian

Number of posts : 577
Location : France
Registration date : 2011-09-09

## Re: Barnard's Star : RV monitoring

ESO press release :

http://www.eso.org/public/france/announcements/ann17036/

Red Dots: The Live Search for Terrestrial Planets around Proxima Centauri Continues

The team behind the Pale Red Dot campaign, who last year discovered a planet around the closest star to our Sun (eso1629), are resuming their search for Earth-like planets and launching another initiative today. The Red Dots campaign will follow the astronomers as they use ESO’s exoplanet-hunter to look for planets around some of our nearest stellar neighbours: Proxima Centauri, Barnard's Star and Ross 154. ESO is joining this Open Notebook Science experiment — real science presented in real time — that will give the public and the scientific community access to observational data from Proxima Centauri as the campaign unfolds
(...)

The Red Dots campaign will keep the public informed via the reddots.space website, where weekly updates will be posted, together with supporting articles and highlights of the week including featured contributions by the community. Conversations will take place also on the Red Dots Facebook page, the Red Dots Twitter account and the hashtag #reddots.
https://reddots.space/

Led_Zep
Jovian

Number of posts : 577
Location : France
Registration date : 2011-09-09

## Re: Barnard's Star : RV monitoring

http://phl.upr.edu/press-releases/barnard

A New Search for Extrasolar Planets from the Arecibo Observatory

"...The National Science Foundation’s Arecibo Observatory and the Planetary Habitability Laboratory of the University of Puerto Rico at Arecibo joined the Red Dots project in the search for new planets around our nearest stars. This new collaboration will simultaneously observe in both the optical and radio spectrum Barnard’s Star, a popular star in the science fiction literature.
Barnard's star is a low-mass red dwarf almost six light-years away and the second-closest stellar system to our Sun after the Alpha Centauri triple-star system. There are hints of a possible super-Earth mass planet in a cold orbit around this star.
The Arecibo Observatory has a new campaign to observe nearby red dwarf stars with planets. The purpose of this campaign is to detect radio emissions from these stars, such as from flares, to help characterize their radiation and magnetic environment and any potential perturbations due to other bodies. These perturbations might reveal the presence of new sub-stellar objects including planets."

Led_Zep
Jovian

Number of posts : 577
Location : France
Registration date : 2011-09-09