The next Kepler news briefing will be held by NASA on February 2. It will be held at NASA headquarters in Washington and carried on NASA Television. The latest results in its search for Earth-size planets in or near the “habitable zone” of other stars (where liquid water can exist) will be presented. 750+ planetary candidates had already been discussed in the first news briefing last year, most of which range from smaller than Neptune to about the size of Earth. Over the next few years many more candidates are expected to be found with many of those to be confirmed after subsequent observations. The actual data release will be on February 1, followed by the press briefing the next day.
The Kepler mission team announced today its first confirmed discovery of a small rocky planet orbiting another star. The planet, Kepler 10-b, has a mass 4.6 times that of Earth, but is only 1.4 times Earth’s diameter, the (again) smallest planet yet found orbiting another sunlike star (not counting the three similar smaller planets found way back in 1991 orbiting a pulsar or dead star). It’s average density is 8.8 grams per cubic centimetre, similar to that of an iron dumbbell. But, it orbits very close to its star, about 20 times closer than Mercury orbits our own sun, and so the surface temperature would be blistering hot and unsuitable for life as we know it. The star is about 560 light years away.
However, it is expected to be the first of many such smaller worlds that Kepler will find, with some in the “habitable zone” of their stars, where temperatures could allow liquid water to exist.
A reminder, too, that the next formal data release from Kepler is scheduled for February 1, 2011, detailing the latest information on an additional 750+ exoplanetary candidates… the current total exoplanet count also now stands at 518!
As noted earlier, I missed posting more the last few weeks due to being sick, but here is a condensed summary of some of the other recent interesting updates as we come to the end of 2010…
Does Pluto, of all places, have a subsurface ocean? This new report says maybe; Cassini has found new evidence for an ice volcano on Titan; the building blocks of life could possibly form on Titan’s surface more easily than thought if there is any liquid water temporarily on the surface from ice volcano eruptions (or comet impacts); there’s a new theory on how Iapetus may have obtained its odd equatorial ridge; the “arsenic life” discovery continues to be criticized by some other scientists (see also here) while the scientists involved have responded and rebutted those claims (see also here); the Spitzer space telescope has found the first known carbon-rich exoplanet; a fourth large exoplanet has been photographed orbiting a star 129 light-years from Earth; another smaller exoplanet, a “super-Earth” was found to have an atmosphere with either high clouds or hot steam; a new study says that the entire Tharsis Rise on Mars should be named the largest known volcano in the solar system instead of the current Olympus Mons (one of four volcanoes that are part of Tharsis Rise); the warm fissures on Enceladus, the source of its water-ice geysers, were seen up-close by Cassini again; there may be another Jupiter-sized planet hiding out in the outer solar system; and finally, the current known exoplanet count is now 516 (and the hope was for at least 500 by the end of this month)!
Highlighted by, among other things, the next exoplanet update from Kepler in February and the launch of Curiosity, the next bigger and better Mars rover, in November, 2011 should also be an interesting year…
For those of you, like myself, who are anxiously waiting for the next major update from the Kepler mission, some good news in case you missed it: the next data release will be on February 1, 2011 instead of the originally planned release in June 2011. This will include the first three months of observations, about 90 days, compared to the first release covering the first 43 days, which yielded 750+ exoplanetary candidates (in addition to the 506 exoplanets already known). How high will the number go now? Any guesses?
The previous post from a few days ago mentioned that the exoplanet count could reach 500 by January according to estimates from astronomers. Well, never mind, it is now only November 20, and the count now stands at 502!
The current count of known exoplanets is now 497. It is being estimated that the number could reach or pass 500 by January. Kepler alone has already found an additional 750+ candidates, just from its first 43 days of operation. These statements from that article, by astronomer Geoffrey Marcy and planetary scientist Sara Seager, sum it up nicely:
“Many of the candidates Kepler discovered are now getting verified with radial velocity confirmations. “On Feb. 1, we’ll announce all of them — a huge avalanche of exoplanet candidates,” Marcy said.”
“The days of having to have perfect exoplanets are going away,” Seager noted. “We’re going to publish so many planets that we’re not going to be able to validate all of them. Instead, we’ll have so many we can start studying them statistically in groups.”
See also this previous article.
A new NASA survey indicates that Earth-sized planets are now thought to be common in the galaxy, and thus, probably the universe. As many as one in four stars similar to the sun could have Earth-sized planets orbiting them.
From the press release:
Nearly one in four stars similar to the sun may host planets as small as Earth, according to a new study funded by NASA and the University of California.
The study is the most extensive and sensitive planetary census of its kind. Astronomers used the W.M. Keck Observatory in Hawaii for five years to search 166 sun-like stars near our solar system for planets of various sizes, ranging from three to 1,000 times the mass of Earth.
All of the planets in the study orbit close to their stars. The results show more small planets than large ones, indicating small planets are more prevalent in our Milky Way galaxy.
“We studied planets of many masses — like counting boulders, rocks and pebbles in a canyon — and found more rocks than boulders, and more pebbles than rocks. Our ground-based technology can’t see the grains of sand, the Earth-size planets, but we can estimate their numbers,” said Andrew Howard of the University of California, Berkeley, lead author of the study. “Earth-size planets in our galaxy are like grains of sand sprinkled on a beach — they are everywhere,” Howard said.
The study is in the Oct. 29 issue of the journal Science.”
See also the University of California press release. These findings would appear to confirm the preliminary findings from the Kepler space telescope as well, in that smaller rocky worlds are more common than larger gas giants, which bodes well in the search for life.
As more exoplanets are found on virtually a weekly basis, it is becoming apparent how diverse they are, sometimes with peculiar characteristics not seen before. Such is the case with the large “hot Jupiter” planet upsilon Andromedae b, which orbits very close to its star and so is searingly hot on the side facing the star (it keeps the same side toward the star, as the moon does as it orbits the Earth). Well, not quite. For some reason, the “hot spot” with the highest temperature is about 80 degrees away, almost on the other side of the planet.
The observations were made using the Spitzer Space Telescope, and astronomers don’t have an explanation yet, but theories include supersonic winds and star-planet magnetic interactions.
This past week, there were two more news items of great interest relating to exoplanets, and the search ultimately for another Earth-like planet.
The first, from the Kepler mission, is that the previously reported possible planet Kepler 9d, only 1.5 times larger than Earth, is likely to soon be announced as confirmed. Other news from the mission will also be announced in November according to the same update.
Then, another very significant announcement from ground-based observatories at the University of California Santa Cruz, the University of Hawaiʻi at Mānoa and the Carnegie Institution of Washington, that for the first time, a small rocky planet has been confirmed orbiting well within the “habitable zone” of a nearby star, the region where temperatures would allow liquid water to exist on a planet; not too hot and not too cold. One of six known planets orbiting the red dwarf star Gliese 581, about 20 light years away, it is estimated to have a mass about three times that of Earth, and a diameter of only about 1.2 to 1.4 times that of Earth. Additional reports here, here and here. A good quote from the UCSC article indicates how planets like this are probably quite common:
The researchers also explored the implications of this discovery with respect to the number of stars that are likely to have at least one potentially habitable planet. Given the relatively small number of stars that have been carefully monitored by planet hunters, this discovery has come surprisingly soon.
“If these are rare, we shouldn’t have found one so quickly and so nearby,” Vogt said. “The number of systems with potentially habitable planets is probably on the order of 10 or 20 percent, and when you multiply that by the hundreds of billions of stars in the Milky Way, that’s a large number. There could be tens of billions of these systems in our galaxy.”
This also brings the total count of known exoplanets so far to 492 and we’ve still only scratched the surface…
In our solar system, all of the gas giant planets have abundant methane in their atmospheres. It was expected that similar planets in other solar systems would also, but one has been found which doesn’t… the planet GJ 436b, about the size of Neptune, orbiting a star 33 light-years from Earth. Based on analysis by the Spitzer Space Telescope, it appears to have almost none, which is a mystery. It should be noted that methane on these types of planets is primordial methane, a very simple molecule, left over from the planets’ original creation. On small rocky planets like Earth and Mars (and it exists on both), it can be either geological or biological in origin. In the case of Mars, the origin is still uncertain.