NASA will hold a news conference at 1 p.m. EST Wednesday, Feb. 22, to present new findings on exoplanets. Exoplanets are planets that orbit stars other than our Sun. The event will air live on NASA Television and the agency's website. Media and the public also may ask questions during the briefing on Twitter using the hashtag #askNASA. www.nasa.gov/…
This sudden announcement sounds very mysterious and tantalizing. NASA is not providing any clues or hints. It states that details of the findings are embargoed by the journal Nature until 1 p.m Wednesday.
Participants include heavy-hitters such as Michael Gillon from the Univ. of Liege in Belgium, Sean Carey from the Spitzer Science Center, Nikole Lewis from the Space Telescope Science Institute and Sara Seager from MIT.
So what has NASA discovered? Some new exoplanet with a strong potential for life or some new info on one of the known ones?
Here are descriptions of a few exoplanets that have been in the news lately and which were discovered by groups associated with the participants.
Kepler-452b
Kepler-452b is an exoplanet orbiting the Sun-like star Kepler-452 about 1,400 light-years from Earth in the constellation Cygnus. Its discovery was announced by NASA on 23 July 2015. It is the first potentially rocky super-Earth planet discovered orbiting within the habitable zone of a star very similar to the Sun.
It is too far to elicit strong interest; at the speed of the New Horizons spacecraft, about 59,000 km/h, it would take approximately 26 million years to get there.
But Kepler-452b is pictured in the news conference announcement on the NASA web-site. Hmmm …
Kepler 186f
Kepler-186f is an exoplanet orbiting the red dwarf Kepler-186, about 500 light-years from Earth. Kepler-186f has 4 other siblings orbiting around its star. See image at the top of the diary.
Kepler-186f was the first Earth-size planet discovered in the potentially 'habitable zone' around another star, where liquid water could exist on the planet's surface. Its star is much cooler and redder than our Sun. If plant life does exist on a planet like Kepler-186f, its photosynthesis could have been influenced by the star's red-wavelength photons, making for a color palette that's very different than the greens on Earth.
55 Cancri e (Janssen)
55 Cancri e is an exoplanet closely orbiting its Sun-like host star 55 Cancri A, a relatively close 40 light-years away. The mass of the exoplanet is about 8.63 Earth masses and its diameter is about twice that of the Earth, thus classifying it as a super-Earth. 55 Cancri e was discovered on 30 August 2004.
Observations from NASA's Spitzer Space Telescope last year revealed extreme temperature swings from one side of the planet to the other, and hints that a possible reason for this is the presence of lava flows. www.jpl.nasa.gov/...
Janssen orbits very close to its star, whipping around it every 18 hours. Because of the planet's proximity to the star, it is tidally locked by gravity; one side of 55 Cancri, referred to as the day side, is always cooking under the intense heat of its star, while the night side remains in the dark and is much cooler. In February 2016, it was announced that NASA's Hubble Space Telescope had detected hydrogen and helium (and suggestions of hydrogen cyanide), but no water vapor.
TRAPPIST-1
Early last year, Michaël Gillon and his group at the University of Liege, using the TRAPPIST telescope at ESO’s La Silla Observatory, discovered a planetary system, 40 light years away in the constellation of Aquarius, containing three Earth-sized planets around an ultracool young red dwarf star slightly bigger than Jupiter in size, known as TRAPPIST-1. While these planets are close to their host star, they are not exposed to very high temperatures and could harbor areas on their surfaces that are suitable for life. reflexions.ulg.ac.be/…
Later in 2016, using NASA's Hubble Space Telescope, astronomers discovered that the exoplanets TRAPPIST-1b and TRAPPIST-1c, are unlikely to have puffy, hydrogen-dominated atmospheres usually found on gaseous worlds. exoplanets.nasa.gov/...
"The lack of a smothering hydrogen-helium envelope increases the chances for habitability on these planets," said team member Nikole Lewis of the Space Telescope Science Institute (STScI) in Baltimore, Maryland.
Wolf 1061
In Dec 2015, UNSW Australia astronomers discovered a potentially habitable planet outside our solar system, orbiting a star a mere 13.8 light-years away. exoplanets.nasa.gov/...
The planet, more than four times the mass of the Earth, is one of three around a red dwarf star called Wolf 1061 in the constellation Ophiuchus.
The three planets orbit the small, relatively cool and stable star about every five, 18 and 67 days. Their masses are at least 1.4, 4.3 and 5.2 times that of Earth, respectively.
“All three planets are of low enough mass to be potentially rocky and have a solid surface, and the middle planet, Wolf 1061c, sits within the ‘Goldilocks’ zone where it might be possible for liquid water – and maybe even life — to exist,” says lead study author UNSW’s Dr. Duncan Wright.
Proxima b
Proxima b is an exoplanet, 4.25 light-years from Earth and is located in the habitable zone of the small red dwarf star Proxima Centauri, one of three stars that make up the Alpha Centauri system. Proxima Centauri is the closest star to the solar system.
Promixa b made waves last year as it was discovered in an orbit that would allow it to have liquid water on its surface, thus raising the possibility of life. www.nasa.gov/...
Researchers think that Proxima b could be an "ocean planet," with an ocean covering its entire surface, the water perhaps similar to that of subsurface oceans detected inside icy moons around Jupiter (Europa) and Saturn (Enceladus).
See www.dailykos.com/… for a diary on Proxima b.
Breakthrough Starshot is an ambitious project by Breakthrough Initiatives to develop a proof-of-concept fleet of tiny centimeter-scale light sail spacecraft, named StarChip, propelled by ground-based lasers, capable of making the journey to the Alpha Centauri star system, at speeds between 15% and 20% of the speed of light. It will take 20 to 30 years to get there, and about 4 years to notify Earth of a successful arrival.
Recent studies however indicate that Proxima b may be subjected to torrents of X-ray and extreme ultraviolet radiation from superflares occurring roughly every two hours. Scientists estimate oxygen would escape Proxima b’s atmosphere in 10 million years. Additionally, intense magnetic activity and stellar wind – the continuous flow of charged particles from a star – exacerbate already harsh space weather conditions. The scientists concluded that it’s quite unlikely Proxima b is habitable. www.nasa.gov/…
Ceres
Ceres is not an exoplanet; it is a dwarf planet in the asteroid belt that lies between the orbits of Mars and Jupiter.
But the Dawn mission recently made news with the discovery of evidence of organic material on the surface of Ceres. The data supports the idea that the organic materials are native to Ceres, not transported by comets or asteroids. The carbonates and clays previously identified on Ceres provide evidence for chemical activity in the presence of water and heat. This raises the possibility that the organics were similarly processed in a warm water-rich environment. Ceres is thought to have a remnant internal ocean of liquid water under a layer of ice.
Exoplanets
Exoplanets are planets that orbit stars other than our Sun. As of 15 February 2017, there are 3,577 confirmed exoplanets in 2,687 planetary systems. en.wikipedia.org/…
The observable universe is estimated to contains 2 trillion galaxies, each containing 100 billion stars on average. Astronomers estimate 100 billion habitable Earth-like planets in our galaxy the Milky Way, 50 sextillion (50x1021) in the observable universe. www.extremetech.com/...
So What is it?
So what has NASA discovered, which warrants a sudden news conference with no details or hints? A new Exoplanet? Signs of life? Proof that we are not alone? A signal from outer space?
Let imagination be your guide!
Further Reading
- Habitable Exoplanets Catalog — phl.upr.edu/…
- List of potentially habitable exoplanets — en.wikipedia.org/…
- Exoplanet wiki — en.wikipedia.org/…
- exoplanets.nasa.gov
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Circumstellar habitable zone (aka Goldilocks zone) — en.wikipedia.org/…
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Exoplanet Proxima b - Water, Ocean, Life? — www.dailykos.com/...