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[TomT]

Download and play the attached unedited audio file for our radio show from 858am to 10am Monday, June 22, 2020

On 6/20/2020 10:35 PM, Jerry wrote:
> Folks
> Here’s Mondays suggested topics. The bottom two are carried over from two weeks ago. We never got to them.
> See you Monday, Jerry
>
> MONDAY, JUNE 22
> ■ In bright twilight look for the slim crescent Moon, less then two days old, low in the afterglow of sunset. It's lower left of Pollux and Castor. Bring binoculars.
> TUESDAY, JUNE 23
> ■ The central stars of the constellation Lyra, forming a small triangle and parallelogram, dangle to the lower right from bright Vega high in the east. The two brightest stars of the pattern, after Vega, are the two forming the bottom of the parallelogram: Beta and Gamma Lyrae, or Sheliak and Sulafat. They're currently lined up vertically. Beta is the one on top.
> Beta Lyrae is an eclipsing binary star. Compare it to Gamma whenever you look up at Lyra. Normally Beta is only a trace dimmer than Gamma. Sooner or later, you'll probably catch Beta when it is definitely fainter than usual.
> One of the best globular clusters, M13, lies half way between Beta and Gamma. It is spectacular in even a small telescope.
> WEDNESDAY, JUNE 24
> ■ Look left of the Moon for Regulus, the brightest star in the constellation of Leo, in late twilight.
> THURSDAY, JUNE 25
> ■ Now spot Regulus to the Moon's lower right.
> ■ As evening grows late, even the lowest star of the big Summer Triangle shines fairly high in the east-southeast. That's Altair, a good three or four fists at arm's length below or lower right of Vega.
> Look left or lower left of Altair, by hardly more than one fist, for the compact little constellation Delphinus, the Dolphin.
> Next, look for Jupiter and Saturn very low three fists to Altair's lower right.
> FRIDAY, JUNE 26
> ■ Every morning now, Venus is getting a little higher and easier to spot in the east-northeast as dawn brightens. It is a thin crescent easily seen in binoculars or a small telescope.
> SATURDAY, JUNE 27
> ■ First-quarter Moon tonight and tomorrow. (The Moon is exactly first-quarter at 4:16 a.m. Sunday morning EDT.) On Saturday evening for North America, the Moon shines in the hind feet of the Leo stick figure, about 8° under Leo's 2nd-magnitude tail-tip star, Denebola.
> Denebola forms an almost perfectly equilateral triangle with brighter Spica off to its left and Arcturus, brighter still, above them. All three sides of the triangle are close to 35° long (35.3°, 35.1°, and 32.8°). This has been called the Spring Triangle, a name that certainly fits.
>
> THIS WEEK'S PLANET ROUNDUP
> Mercury is lost in the sunset.
> Venus is low in the dawn; look for it just above the east-northeast horizon. Look early enough before dawn grows bright, and you may be able to catch the Pleiades 9° above it. Binoculars help. Venus is on its way up to a fine showing as the bright Morning Star through summer and fall.
> Mars rises in the east around 1 a.m. daylight saving time, shining bright orange (magnitude –0.4) at the Aquarius-Pisces border. Watch for it to clear the horizon lower right of the Great Square of Pegasus. By the first light of dawn, Mars shines high and prominent in the southeast.
> In a telescope Mars has grown to 11 arcseconds in apparent diameter; we're approaching it as Earth speeds along in our faster orbit around the Sun. Mars is as gibbous as it gets, 84% sunlit. Look for the bright South Polar cap and for subtler dark surface markings.
> Mars will appear fully twice this diameter when it passes closest by Earth around opposition in the first half of October.
> Jupiter and Saturn (magnitudes –2.7, and +0.3, respectively) now rise around the end of twilight: Jupiter first, then dimmer Saturn following about 20 minutes behind, lower left of Jupiter. They're 5½° apart. Farther to Jupiter's right, the Sagittarius Teapot rests upright.
> The two giant planets shine at their highest and telescopic best around 2 or 3 a.m. daylight-saving time. They straddle the border of Sagittarius and Capricornus. Jupiter will reach opposition on the night of July 13th, Saturn on July 20th.
> Uranus (magnitude 5.8, in Aries) is very low in the east just before dawn.
> Neptune (magnitude 7.9, in Aquarius) is well up in the southeast before dawn begins, in the vicinity of Mars.
>
>
> Earth like planet around a Sun like star.
> By Katy Pallister   > 05 JUN 2020, 15:30
> In amongst archived data from the Kepler mission, a team of German and American researchers has identified an Earth-like planetary candidate, KOI-456.04, situated within its host star’s habitable zone. What sets this discovery apart from other known Earth-like exoplanets is that its star, Kepler-160, bears a striking resemblance to our Sun. Although the planet’s presence is yet to be confirmed, this exoplanet-star pairing could be one of the closest matches to the Earth-Sun system that we’ve found so far.
> “KOI-456.01 is relatively large compared to many other planets that are considered potentially habitable,” Dr René Heller of Max Planck Institute for Solar System Research, Germany, and lead author of the research, said in a statement. “But it’s the combination of this less-than-double the size of the Earth planet and its solar type host star that make it so special and familiar.”
> Located over 3,000 light-years away from Earth, the star Kepler-160 is around 1.1 times the size of the Sun and has a surface temperature of 5200˚C, only 300 degrees less than Sun. The star is already known to have two exoplanets – Kepler-160 b, a rocky super-Earth, and Kepler-160 c, a Neptune-like gas giant – but the duo’s orbits are very close to the star, and are thought to be too hot to be habitable. Yet the possibility of a third planet, hinted at by variations in Kepler-160 c’s orbital period, tempted astronomers to take another look at the planetary system.
> Both previous planets were discovered by searching for periodic dips in Kepler-160’s brightness that indicates a transiting object. However, these temporary dimmings are hard to detect from smaller exoplanets, therefore Heller and his team created a new search algorithm that could more accurately pinpoint the presence of these planets.
> Lo and behold their improved approach found KOI-456.04. With an incredibly similar orbital period to Earth of 378 days, KOI-456.04 lies at a distance from Kepler-160 conducive to the existence of liquid water. But further analysis showed that this was not the culprit of Kepler-160 c’s distortions. There was in fact another non-transiting planet that was responsible, Kepler-160 d.
> “Our analysis suggests that Kepler-160 is orbited not by two but by a total of four planets,” Heller said.
> As described in their paper, published in Astronomy and Astrophysics, indirectly confirmed Kepler-160 d has a mass between 1 and 100 Earth masses, and an orbital period from 7 to 50 days. However, this planet has fallen into the shadows of the more intriguing combination of the Earth-like KOI-456.04 orbiting within the habitable zone of the Sun-like Kepler-160.
> Most Sun-like stars discovered by Kepler have a Neptune-sized planet in a much closer orbit, too hot to be habitable (like Kepler-160 c). On the flip-side other Earth-sized planets that have been found in a star’s habitable zone, have tended to have red dwarfs as hosts – small, faint stars with a low surface temperature. These stars also differ from the Sun, in that they emit mostly infra-red radiation, rather than the visible light that we receive from the Sun. For this reason, amongst many others, the habitability of planets around red dwarfs is heavily debated.
> However, these concerns are not shared for Kepler-160, as not only does it radiate visible light, but it does so at a luminosity similar to the Sun. Meaning that newly found KOI-456.04 receives about 93 percent of the amount of sunlight that we experience on Earth. The researchers suggest that if KOI-456.04 were to have an inert atmosphere with a mild Earth-like greenhouse effect its surface temperature would be around 5˚C, roughly 10˚C less than Earth’s average temperature.
> Boasting an 85 percent chance of planetary possibility, KOI-456.04 has not yet reached the 99 percent benchmark needed for full confirmation. Astronomers suspect that they may need to wait for future space missions, such as ESA’s PLATO spacecraft before they get complete validation.
>
>
> Mars may have once had a giant ring that eventually got smooshed to form one of its oddly-shaped moons, new research suggests.
> Mars has two small, lumpy moons, Phobos and Deimos. Phobos orbits closer to the Red Planet and follows the line of Mars' equator. Deimos orbits farther away, along an orbit that's tilted by 2 degrees off the plane of the Martian equator. The wonky orbit adds evidence to the idea that Phobos may once have been a giant ring that eventually coalesced into its present shape.In 2017, a team of researchers argued in the journal Nature Geoscience that the Martian moons go through cycles — ripped apart into thin rings by the planet's gravity, then eventually forming moons again. In each cycle, the moon formed from the ring is smaller than its former self, with bits of the rings falling out of orbit and drifting out into space. Over billions of years, generations of moons would have gone through these cycles of ring-moon-ring, scientists suspect.
> Now, in a new paper published June 1 to the arXiv database,which has not yet been peer-reviewed, an team of researchers (some who were involved in the Nature Geoscience paper) showed that an ancient Martian moon, 20 times the size of Phobos, could have jostled Deimos into its current orbit.
> “The fact that Deimos' orbit is not exactly in plane with Mars' equator was considered unimportant, and nobody cared to try to explain it," lead author Matija Ćuk, a research scientist at the SETI Institute in Mountain View, California, said in a statement. "But once we had a big new idea and we looked at it with new eyes, Deimos' orbital tilt revealed its big secret."
> Two moons that follow similar paths around a planet can end up in a situation called "orbital resonance" where one bobs up and down around the other's orbit. As Live Science has previously reported, two moons of Neptune are currently resonating with each other like this.
> Here's what the scientists think happened in this ring-moon cycle to explain the current Mars setup: Deimos formed billions of years ago, and since it has sort of just been overlooking the dynamic ring-moon party. Over that same time, a giant ring encircling Mars got squished into a moon (or moons), dispersed back into a ring and then into a moon again, and so on. During one of these iterations, one of the moons (the giant mystery moon) knocked Deimos into its current ring, and then just like that this mystery moon vanished into its ring form. Then, a remnant of that ring, the scientists suspect, formed Phobos, which is the younger of the two Martian satellites.
> In order for this theory to work, the long-lost moon that formed out of a Martian ring would have needed to start moving away from Mars and into a resonance with Deimos that would have produced the more distant moon's current, angled orbit.
> Eventually, part of the ring-moon cycle will repeat again. The younger moon Phobos is losing altitude over Mars, and researchers expect that it will eventually break up and form a disintegrating ring around the planet.
> That will leave little Deimos orbiting alone, with only its lopsided orbit as a record of what else used to exist around Mars.
>