The Fainting of Betelgeuse — Update

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This enormous star seems to be fading fast.

Spaceweather.com

Jan. 10, 2020: One day, perhaps in our lifetimes, perhaps a million years from now, the red giant Betelgeuse will dim a little–and then explode. The resulting supernova will rival the full Moon and cast shadows after dark, completely transforming the night skies of Earth. No wonder astronomers are closely tracking the current “fainting of Betelgeuse.”

“Fainting” is an actual astronomical term. It means dimming, the opposite of brightening. And right now, Betelgeuse is definitely fainting.

 Betelgeuse photographed by Brian Ottum of Animas, New Mexico, almost 4 years apart using the same telescope and observing methods. 

Edward Guinan of Villanova University and colleagues caused a minor sensation last month when they reported “[Betelgeuse] has been declining in brightness since October 2019, now reaching a modern all-time low of V = +1.12 mag on 07 December 2019 UT. Currently this is the faintest the star has been during our…

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Multiple resonances of the eight planet system of Kepler-90, part 2

Kepler-90 Planets Orbit Close to Their Star [credit: NASA/AMES]

In part 1 we looked at the inner four planets: b,c,i and d. Here in part 2 we’ll look at the outer four: e,f,g and h – with a dash of d included.

The largest planet in the system is h, the outermost of the eight so far found, and it’s about the same size as Jupiter. It’s ‘an exoplanet orbiting within the habitable zone of the early G-type main sequence star Kepler-90’, says Wikipedia. However, ‘it is a gas giant with no solid surface’, so probably no aliens lurking there.

It wasn’t that easy to find synodic patterns of interest, but here we have two examples, both involving planet h.

Multiple resonances of the eight planet system of Kepler-90, part 1

Golden rectangle: Fibonacci spiral

Unusually, the eight planets in the Kepler-90 system were found using machine learning. “It’s very possible that Kepler-90 has even more planets that we don’t know about yet,” NASA astronomer Andrew Vanderburg said.
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From Wikipedia’s Near resonances section on exoplanet Kepler-90:

“Kepler-90’s eight known planets all have periods that are close to being in integer ratio relationships with other planets’ periods; that is, they are close to being in orbital resonance.

The period ratios b:c, c:i and i:d are close to 4:5, 3:5 and 1:4, respectively (4: 4.977, 3: 4.97 and 1: 4.13) and d, e, f, g and h are close to a 2:3:4:7:11 period ratio (2: 3.078: 4.182: 7.051: 11.102; also 7: 11.021).

f, g and h are also close to a 3:5:8 period ratio (3: 5.058: 7.964). Relevant to systems like this and that of Kepler-36, calculations suggest that the presence of an outer gas giant planet facilitates the formation of closely packed resonances among inner super-Earths.”
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Let’s look at it another way i.e. at the synodic periods rather than the orbit ratios, as these tend to deliver more clear-cut results, starting with a model for the first four planets: b,c,i and d, which we’ll call the inner planets. Their orbits of the star are in a range of 7-60 days.

Quantization of Planetary Systems and its Dependency on Stellar Rotation

Solar system planets [image credit: BBC]

Well this looks interesting. Jean paul Zoghbi has discovered half integer relationships between star rotation rates and their planetary system’s angular momenta. The paper is here

Abstract With the discovery of now more than 500 exoplanets, we present a statistical analysis of the planetary orbital periods and their relationship to the rotation periods of their parent stars. We test whether the structural variables of planetary orbits, i.e. planetary angular momentum and orbital period, are `quantized’ in integer or half-integer multiples of the parent star’s rotation period. The Solar System is first shown to exhibit quantized planetary orbits that correlate with the Sun’s rotation period.

Six hot rocky exoplanets orbiting very close to their stars could shed light on the geology of planets in our solar system

A researcher said of one of the new finds: “It is hard to see how the planet got there!”
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Six ‘very hot’ rocky exoplanets orbiting stars in the local region of the Milky Way hold the key to understanding more about how the Earth was formed, astronomers claim.

Researchers from the Open University have been studying planets discovered by the European Space Observatory’s planet-hunting telescope in Chile.

They are orbiting stars between 160 and 440 light years from Earth and all have hot surfaces with temperatures of around 2,012F to 3,272F.

The new findings could shed light on the geology of Earth and other rocky planets in the Solar System including Mercury, Venus and Mars, researchers say.

Full Daily Mail report here.

SDO sees new kind of magnetic explosion on sun

The article also explains why ‘understanding forced reconnection can help modelers better predict when disruptive high-energy charged particles might come speeding at Earth.’

NASA’s Solar Dynamics Observatory has observed a magnetic explosion the likes of which have never been seen before, reports Phys.org.

In the scorching upper reaches of the Sun’s atmosphere, a prominence—a large loop of material launched by an eruption on the solar surface—started falling back to the surface of the Sun.

But before it could make it, the prominence ran into a snarl of magnetic field lines, sparking a magnetic explosion.

How to Shape a Spiral Galaxy

Spiral galaxy NGC 5457 aka the Pinwheel Galaxy [image credit: European Space Agency & NASA]

No mention of electricity here, although it’s required to create the magnetism: ‘The magnetic behavior of a material depends on its structure, particularly its electron configuration’ – Wikipedia. We’re told these electromagnetic forces stretch for 24,000 light years in one galaxy, but understanding them is still in its infancy.

New observations from SOFIA are shedding light on how spiral-shaped galaxies, like our own Milky Way, get their iconic shape, says NASA.

Our Milky Way galaxy has an elegant spiral shape with long arms filled with stars, but exactly how it took this form has long puzzled scientists. New observations of another galaxy are shedding light on how spiral-shaped galaxies like our own get their iconic shape.

Magnetic fields play a strong role in shaping these galaxies, according to research from the Stratospheric Observatory for Infrared Astronomy, or SOFIA.

Resonances of the first (pulsar) exoplanetary system ever found

Poster from the NASA Exoplanets Exploration Program’s Exoplanet Travel Bureau [credit: NASA/JPL-CalTech]

Before we start – ‘Pulsar planets are planets that are found orbiting pulsars, or rapidly rotating neutron stars.’

Wikipedia tells us:
‘PSR B1257+12, previously designated PSR 1257+12, […] is a pulsar located 2,300 light-years from the Sun in the constellation of Virgo. It is also named Lich, after a powerful, fictional undead creature of the same name.

The pulsar has a planetary system with three known planets, named “Draugr” (PSR B1257+12 b or PSR B1257+12 A), “Poltergeist” (PSR B1257+12 c, or PSR B1257+12 B) and “Phobetor” (PSR B1257+12 d, or PSR B1257+12 C), respectively.

They were both the first extrasolar planets and the first pulsar planets to be discovered; B and C in 1992 and A in 1994.

A is the lowest-mass planet yet discovered by any observational technique, with somewhat less than twice the mass of Earth’s moon.’

Neptune’s moons locked in ‘dance of avoidance’

Neptune Moon Dance: This animation illustrates how the odd orbits of Neptune’s inner moons Naiad and Thalassa enable them to avoid each other as they race around the planet. (courtesy: JPL)

Well, this is fun. Need we say more?

Even by the wild standards of the outer solar system, the strange orbits that carry Neptune’s two innermost moons are unprecedented, according to newly published research.

Orbital dynamics experts are calling it a “dance of avoidance” performed by the tiny moons Naiad and Thalassa, says Space Newsfeed.

The two are true partners, orbiting only about 1,150 miles (1,850 kilometers) apart.

One of the closest exoplanet pairs to the 3:2 mean motion resonance: K2-19b and c

Artist’s impression of the Kepler telescope [credit: Wikipedia]

So said researchers in their 2015 study which had that title. Then a third planet was seen.

In the abstract they say:

Methods. Our search through two separate pipelines led to the independent discovery of K2-19b and c, a two-planet system of Neptune-sized objects (4.2 and 7.2 R⊕), orbiting a K dwarf extremely close to the 3:2 mean motion resonance. The two planets each show transits, sometimes simultaneously owing to their proximity to resonance and the alignment of conjunctions.

The rotation of Venus

Credit: infobarrel.com

Not mentioned in the report (or anywhere else we know of) is that 19 Venus rotations very closely match the period of 13 lunar tropical years of 13 orbits/rotations each: (169 * 27.321582 days) / 19 = 243.01827 days. This matches the 1991 Magellan observation of the Venusian rotation period 243.0185 days and is very close to the current estimate, which is that it averages 243.0212 +- .00006 days but seems to have a small degree of variability, for reasons yet to be confirmed.

Venus is covered in a thick layer of clouds, one reason that it appears so bright in the sky, says Phys.org.

Ancient astronomers had a good idea of what (since Copernicus) we know as its orbital period; the modern measurement is that Venus takes 224.65 days to complete one revolution around the Sun, a Venusian year.

Because of the clouds, however, it has been difficult to measure the length of the Venusian day since the nominal method of watching a visible surface feature rotate around 360 degrees is not possible.

Resonances of the Kepler-184 three-planet system

There doesn’t seem to be any online discussion of this planetary system, first seen in 2014 – but it turns out be interesting anyway.

This is a Lucas series set-up, the planets being b, c, and d in order of proximity to the star.

Starting with the orbits:
19 b = 203.006394 days
10 c = 203.03005
7 d = 203.1565
(data: exoplanet.eu)

Mr Yoshimura would agree…

…with the period of ~2500 years in our 2015 blog post: Why Phi? – Jupiter, Saturn and the de Vries cycle (we use 2503y).

Or he might do, if he had read it. More correctly, we agree with him.

In the second paragraph of the introduction in his article of December 1978 in the Astrophysical Journal, which has a rather long title related to the solar cycle, he writes:

A new run of the CLOUD experiment examines the direct effect of cosmic rays on clouds

As this is going on, cosmic rays are near a record high since measurements began. Researchers are using natural cosmic rays this time.

CERN’s colossal complex of accelerators is in the midst of a two-year shutdown for upgrade work.

But that doesn’t mean all experiments at the Laboratory have ceased to operate.

The CLOUD experiment, for example, has just started a data run that will last until the end of November, reports Phys.org.

The CLOUD experiment studies how ions produced by high-energy particles called cosmic rays affect aerosol particles, clouds and the climate.

NASA quip: ‘Honey I Shrunk the Planetary System’

The Kepler-42 system as compared to the Jovian system [credit: NASA/JPL-Caltech]

The headline was NASA’s joke about both the size and the short orbit periods (all less than two days) of the three planets in the Kepler-42 system.

The discovery of this system dates back to 2012, but there don’t seem to be any numbers on resonant periods, so we’ll supply some now.

Wikipedia says:
‘Kepler-42, formerly known as KOI-961, is a red dwarf located in the constellation Cygnus and approximately 131 light years from the Sun. It has three known extrasolar planets, all of which are smaller than Earth in radius, and likely also in mass.’

‘On 10 January 2012, using the Kepler Space Telescope three transiting planets were discovered in orbit around Kepler-42. These planets’ radii range from approximately those of Mars to Venus. The Kepler-42 system is only the second known system containing planets of Earth’s radius or smaller (the first was the Kepler-20 system). These planets’ orbits are also compact, making the system (whose host star itself has a radius comparable to those of some hot Jupiters) resemble the moon systems of giant planets such as Jupiter or Saturn more than it does the Solar System.’

The three planets in order of distance from their star (nearest first) are c,b and d. They all have very short orbit periods ranging from under half a day to less than two days, and the star has only 13% of the power of our Sun.

A nearby binary star system with four planets

Pairs or multiple systems of stars which orbit their common center of mass. If we can measure and understand their orbital motion, we can estimate the stellar masses.

Relatively nearby, that is…

‘Upsilon Andromedae is located fairly close to the Solar System… (44 light years). Upsilon Andromedae A has an apparent magnitude of +4.09, making it visible to the naked eye even under moderately light-polluted skies, about 10 degrees east of the Andromeda Galaxy.’ – Wikipedia

The larger of the binary stars is ups_And A, which has 4 planets orbiting it: b,c,d and e.

The information on this star system was recently updated, so let’s have a look.

TESS discovers habitable zone planet in GJ 357 system

Credits: NASA’s Goddard Space Flight Center/Chris Smith

Following the report we analyse the orbital data for evidence of resonances.

A planet discovered by NASA’s TESS has pointed the way to additional worlds orbiting the same star, one of which is located in the star’s habitable zone, reports SciTechDaily.

If made of rock, this planet may be around twice Earth’s size.

The new worlds orbit a star named GJ 357, an M-type dwarf about one-third the Sun’s mass and size and about 40% cooler that our star. The system is located 31 light-years away in the constellation Hydra.

In February, TESS cameras caught the star dimming slightly every 3.9 days, revealing the presence of a transiting exoplanet — a world beyond our solar system — that passes across the face of its star during every orbit and briefly dims the star’s light.

Why Phi? – exoplanetary resonances of HD 40307

Moons of Pluto

This one may have slipped through the net, so to speak. The link to Pluto is explained below.

Star HD 40307 has six planets orbiting between 7 and 198 days, but here the focus will be on the outer three: e, f and g. These were reported in 2012 (whereas b, c, and d were found in 2008).

However, it seems the resonances described below have been overlooked, if lack of related internet search results can be relied on.

NASA’s TESS discovered three new planets nearby, including temperate ‘sub-Neptune’

Credit: NASA’s Goddard Space Flight Center / Scott Wiessinger

Quoting from the abstract of the study in Nature Astronomy:
‘The planets orbit close to a mean-motion resonant chain, with periods (3.36 days, 5.66 days and 11.38 days, respectively) near ratios of small integers (5:3 and 2:1).’

One of the astronomers said: “For TOI-270, these planets line up like pearls on a string. That’s a very interesting thing because it lets us study their dynamical behavior. And you can almost expect, if there are more planets, the next one would be somewhere further out, at another integer ratio.”

“There is a good possibility that the system hosts other planets, further out from planet d, that might well lie within the habitable zone. Planet d, with an 11-day orbit, is about 10 million kilometers out from the star.”

In fact the distance-to-star ratios of the planets (named b,c and d) are very similar:
b:c = 1:1.542 and c:d = 1:1.553 (for comparison Earth:Mars is 1:1.524).

NASA’s Transiting Exoplanet Survey Satellite, or TESS, has discovered three new planets that are among the smallest, nearest exoplanets known to date, reports Tech Explorist.

The planets circle a star only 73 light-years away and incorporate a small, rough super-Earth and two sub-Neptunes — planets about a large portion of the size of our own icy giant.

The sub-Neptune farthest out from the star seems, by all accounts, to be inside a temperate zone, implying that the highest point of the planet’s atmosphere is inside a temperature extend that could support a few types of life.

NASA goes with low Solar Cycle 25 prediction “30-50% lower than cycle 24.”

Quiet sun [image credit: NASA]

NASA finally agrees with our model estimate for cycle 25 published in 2013. It’ll be interesting to see how this pans out. Leif Svalgaard predicted that cycle 25 would be higher than 24, but lower than cycle 20.

Research now underway may have found a reliable new method to predict this solar activity. The Sun’s activity rises and falls in an 11-year cycle. The forecast for the next solar cycle says it will be the weakest of the last 200 years. The maximum of this next cycle – measured in terms of sunspot number, a standard measure of solar activity level – could be 30 to 50% lower than the most recent one. The results show that the next cycle will start in 2020 and reach its maximum in 2025.

The new research was led by Irina Kitiashvili, a researcher with the Bay Area Environmental Research Institute at NASA’s Ames Research Center, in California’s Silicon Valley. It combined observations from two NASA space missions – the Solar and Heliospheric Observatory and the Solar Dynamics Observatory – with data collected since 1976 from the ground-based National Solar Observatory.