Red dots is a project to attempt detection of the nearest terrestrial planets to the Sun. Terrestrial planets in temperate orbits around nearby red dwarf stars can be more easily detected using Doppler spectroscopy, hence the name of the project.

For the 2017 campaign we will be focused on three of these red-dwarfs. The observational strategy is the same on all three objects. We will obtain about 90 observations with HARPS (weather permitting) spread over 100 nights while obtaining quasi-simultaneous photometry with different observatories all over the world.

Proxima Centauri – The Pale Red Dot campaign confirmed the existence of a persistent Doppler signal in different datasets. This was interpreted as the presence of Proxima b, a 1.3 Earth mass planet orbiting in a temperate orbit around the star. In addition to this, the 2016 and historical data also show very strong evidence of at least one more signal in the period range of 40-400 days, and some possible hints of additional signals in periods shorter than 6 days. The goal of this campaign is to accumulate more measurements to cover a more substantial part of the 40+ days signal and explore whether or not it is connected with stellar activity (cool spots co-rotating with the star) or it is better explained by the presence of a few Earth-mass planet in cold orbits. Similarly, the increased number of measurements and a more detailed modelling of stellar activity might reveal the presence of additional planets in short periods.

Shining brightly in this Hubble image is our closest stellar neighbour: Proxima Centauri. Image credits. ESA/Hubble & NASA

For more information on the star visit its rather detailed the wikipedia entry here. For more information about the previous planet searches, visit Pale Red Dot. All technical information and scientific references can be found via Simbad.

Barnard’s star – There is no robust claim of a planet orbiting this star so far. Barnard’s star is an old halo red dwarf, meaning that it has very low activity levels. With the new set of measurements, we should be able to sample the temperate orbits down to sub-Earth mass objects and confirm the hints of a possible super-Earth mass planet in a cold orbit that is already hinted in historical HARPS, UVES and Keck HIRES data. Barnard’s star is the second stellar system to the Sun beyond Alpha Centauri, and also a prime target for future detailed characterization and -may be one day- in situ exploration.

Barnard’s star is also known to astronomers as the star with highest proper motion. That is, due to its proximity to the Sun and its relatively large motion across the galaxy, it has the largest apparent motion of any known object beyond the solar system. There are numerous other stars than move intrinsically faster, but they are too far away for make this motion so apparent to the eye. The motion is large enough that we should see it moving against the background stars during the Red Dots 2017 campaing (time-lapse to be presented as soon as we start collecting data). For more detailed information on the star and previous planet claims and searches, visit its wikipedia article here

Ross 154 – As opposed to the other two, Ross 154 (also known as Gliese 729) is a fast rotating star. With a suspected rotation period of less than 3 days, its activity levels are rather higher as well including energetic flares. We suspect that the star is not radically different from other red dwarf, but that its enhanced activity levels are due to its young age. Detecting planets with the Doppler technique around active stars is challenging, because the fast rotation will -almost for sure- induce spurious Doppler signals in the same time-scales of rotation. Intensive multi-colour photometric follow-up should enable precise modelling of the stellar surface and allow filtering out all this activity. Similar experiments have been tried before with limited success. The novelty here is the very regular sampling with the simultaneous multi-colour photometry. Will we be able to unambiguously identify bonafide planet signals around this stormy object?

Star field around the current position of Ross 154. The image of the star appears in two different colours because the image is a composite of two colour images (red and blue) taken a few years apart. Created using Aladin v9.0.