The recent discovery of Proxima b1, a habitable Earth-mass planet next to the nearest star, opened a unique opportunity in the search for extra-terrestrial life. It is much easier to study nearby habitats for life, either by remote sensing of the feeble radiation signals from biologically-produced molecules (e.g. oxygen) or by sending spacecrafts that will image the planet’s surface or collect samples from its atmosphere through a close encounter.
A new international campaign called Red Dots launched Monday, with its mission to search for planets around nearby star systems, and to understand if those planetary bodies can sustain life as we know it. The team behind the campaign discovered Proxima b in 2016, which is the closest planet to Earth outside our solar system.The campaign’s scientific team, led by Guillem Anglada-Escudé from Queen Mary University of London, will use a number of instruments around the world, including the European Southern Observatory’s High Accuracy Radial velocity Planet Searcher (HARPS), to acquire data, ESO said in a statement Monday. Photometric observations began June 15, spectrographic observations will begin Wednesday, and the data will be gathered over approximately 90 days.
The chemistry of life as we know, says Harvard’s Avi Loeb, head of Harvard’s Department of Astronomy and director of Harvard’s Black Hole Initiative, requires liquid water, but also being at the right distance from the host star for a comfortable temperature on the planet’s surface, is not a sufficient condition. The planet also needs to have an atmosphere. In the absence of an external atmospheric pressure, the warming of water ice transforms it into directly into gas phase rather than liquid.
The warning sign is just next door: Mars has a tenth of the Earth’s mass and lost its atmosphere. Does Proxima b have an atmosphere? If so, the atmosphere and any surface ocean it sustains, will moderate the temperature contrast between its permanent day and night sides. The James Webb Space Telescope, scheduled for launch in October 2018, will be able to distinguish between the temperature contrast expected if Proxima b is bare rock compared to the case where its climate is moderated by an atmosphere.
Proxima Centauri is a red dwarf star with 12% of the mass of the Sun. Another dwarf star, TRAPPIST-1, with 8% of the solar mass, was discovered recently to host 3 habitable planets out of a total of 7 and if life forms in one of the three it will likely spread to the others. Such dwarf stars have a lifetime that is up to a thousand times longer than the Sun. Hence, they provide excellent prospects for life in the distant future, a trillion years from now, long after the Sun will die and turn into an Earth-size cold remnant, known as a white dwarf.
But this also raises an important scientific question: is life most likely to emerge at the present cosmic time near a star like the Sun? By studying the habitability of the Universe throughout cosmic history from the birth of the first stars 30 million years after the Big Bang to the death of the last stars in ten trillion years, Loeb concluded that unless habitability around low mass stars is suppressed, life is most likely to exist near dwarf stars like Proxima or TRAPPIST-1 ten trillion years from now.
This highlights the importance of searching for life around these nearby red dwarf stars, namely the Red Dots campaign. Finding bio-signatures in the atmospheres of transiting Earth-mass planets around such stars will determine whether present-day life is indeed premature or typical from a cosmic perspective.
The Red Dots campaign will follow astronomers as they look for planets around some of our nearest stellar neighbors. The target stars this time are Proxima Centauri (which the scientists suspect may have at least one more terrestrial planet in orbit around it), Barnard’s Star, a red dwarf star just six light-years away shown at the top of the page, and Ross 154, another red dwarf at a distance of nearly 10 light-years.
The team will acquire and analyse data from the High Accuracy Radial velocity Planet Searcher (HARPS) instrument on the European Southern Observatory’s 3.6-metre telescope in Chile and other instruments across the globeover approximately 90 nights.
HARPS is a spectrograph with unrivalled precision — the most successful finder of low-mass exoplanets to date. Attached to the ESO 3.6-metre telescope at La Silla, HARPS searches nightly for exoplanets, looking for the minute wobbles in the star’s motion, generated by the pull of an exoplanet in orbit. HARPS picks up motions which can be as little as a gentle walking pace — just 3.5 km/h — from trillions of kilometres away.
In addition to the HARPS instrument, the Red Dots campaign will use an extensive network of small telescopes for photometric monitoring including: Las Cumbres Global Observatory Telescope network; SpaceObs ASH2 in Chile; Observatorio de Sierra Nevada, in Spain; and Observatori Astronomic del Montsec, Spain. Alongside the new data, the team will make extensive use of public observations of all three stars from the ESO archives (HARPS and UVES/VLT) and the ASAS photometric survey
Photometric observations began on 15 June and spectrographic observations start on 21 June. The Red Dots initiative — presenting real science in real time — will give the public and the scientific community direct access to the observational data from at least Proxima Centauri as the campaign unfolds.
Conversations with the scientists will be encouraged via a forum where more scientific and technical details can be shared. In addition to this, the team will welcome contributions from professional and amateur astronomers to assist in the photometric follow up of all three targets in collaboration with the American Association of Variable Star Observers.
The Red Dots campaign will keep the public informed via the reddots.space website and forum where weekly updates will be posted, together with supporting articles and featuring the highlights of the week from the community. Conversations will take place also on the Red Dots Facebook page, the Red Dots Twitter account and via the hashtag #reddots.
The outreach campaign is being coordinated by members of the science team with support from the outreach departments of ESO, Queen Mary University of London, Instituto de Astrofisica de Andalucia/CSIC, Universidad de Chile and University of Goettingen.
No one can say for sure what the outcome of the Red Dots campaign will be. Any observations presented during this time will of course be preliminary only and they must not be used or cited in refereed literature. The team will not produce conclusive statements, nor claim any finding until a suitable paper is written, reviewed and accepted for publication in a scientific journal. The purpose of the campaign is to open the scientific process to public view, but not circumvent the peer review process.
Post completo en: The Daily Galaxy