Archive for the ‘Astrophysics’ Category

Super-sized exoplanet rings [credit: Ron Miller / Astronomy Now]

Super-sized exoplanet rings [credit: Ron Miller / Astronomy Now]


They say ‘the diameter of the ring system is nearly 120 million kilometres’. Imagine the forces in play to keep all that in order. Astronomy Now reports:

Astronomers at the Leiden Observatory, The Netherlands, and the University of Rochester, USA, have discovered that the ring system that they see eclipse the very young Sun-like star J1407 is of enormous proportions, much larger and heavier than the ring system of Saturn. The ring system — the first of its kind to be found outside our Solar System — was discovered in 2012 by a team led by Rochester’s Eric Mamajek.

A new analysis of the data, led by Leiden’s Matthew Kenworthy, shows that the ring system consists of over 30 rings, each of them tens of millions of kilometres in diameter. Furthermore, they found gaps in the rings, which indicate that satellites (“exomoons”) may have formed. The result has been accepted for publication in the Astrophysical Journal.

Read the rest here.

Prediction using Titus-Bode Relation

Posted: April 15, 2015 by tchannon in Astrophysics

Ian Wilson suggests this paper ought to be aired.

Image

 

Exoplanet Predictions Based on the Generalised Titius-Bode Relation
Timothy Bovaird, Charles H. Lineweaver

ABSTRACT
We evaluate the extent to which newly detected exoplanetary systems containing at least four planets adhere to a generalized Titius-Bode (TB) relation. We find that the majority of exoplanet systems in our sample adhere to the TB relation to a greater extent than the Solar System does, particularly those detected by the Kepler mission. We use a generalized TB relation to make a list of predictions for the existence of 141 additional exoplanets in 68 multiple-exoplanet systems: 73 candidates from interpolation, 68 candidates from extrapolation. We predict the existence of a low-radius (R < 2.5R ? ) exoplanet within the habitable zone of KOI-812 and that the average number of planets in the habitable zone of a star is 1-2. The usefulness of the TB relation and its validation as a tool for predicting planets will be partially tested by upcoming Kepler data releases.
http://arxiv.org/abs/1304.3341
— Open access PDF from there

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Exoplanet link to Lucas number series

Posted: March 31, 2015 by oldbrew in Astrophysics
Tags: ,

Jupiter-sized exoplanet [Wikipedia]

Jupiter-sized exoplanet [Wikipedia]


Tallbloke has spotted a science paper about exoplanets where one system has two planets whose orbital periods are close to 11:4 ratio Lucas numbers.

Paper: ‘We also refine the parameters of two planets announced previously around HD 113538, based on a longer series of measurements. The planets have a period of 663± 8 and 1818 ± 25 days, orbital eccentricities of 0.14 ± 0.08 and 0.20 ± 0.04, and minimum masses of 0.36 ± 0.04 and 0.93 ±0.06 MJup.’
[MJup = mass of Jupiter]

The outer planet is slightly smaller than Jupiter and the inner one is about one third of it, by mass. Noting the uncertainties in the orbital periods, we can see how closely they relate to the Lucas ratio:
663/3 = 221 = 55 x 4, +1
1818/3 = 606 = 55 x 11, +1
difference = 55 x 7

This is very close to 4:11 orbit ratios with 7 conjunctions in that time period, 4-7-11.
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Drill into Mars for clues to Earth’s climate

Posted: March 5, 2015 by oldbrew in Astrophysics, climate
Tags:
River Thames in 1677

River Thames in 1677

New Scientist has a new angle on the Little Ice Age, asking: ‘Can Martian holes give climate clues?’

Digging a hole on another world may settle a nagging question about Earth’s climate.

From about 1300 to 1870, much of the Earth is thought to have endured a long cold snap dubbed the Little Ice Age. If such a freeze occurred, it is usually blamed on a dip in solar activity, but there are other suspects such as volcanoes.

If the sun was responsible, we should see evidence of it across the solar system, says Ralph Lorenz of the Johns Hopkins University Applied Physics Lab in Laurel, Maryland. To settle the debate, he suggests digging a hole on Mars to see if it, too, had an ice age around that time.

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Back in 1987, Robert M Wilson of NASA’s Space Science Laboratory in Huntsville published this paper in the Journal of Geophysical Research. It’s important to our solar-planetary theory because it shows that the Sun is bi-modal in terms of its solar cycle lengths. They cluster around  periods of a little over ten and a little under twelve years. These periods correlate to the periods of Jupiter-Earth-Venus syzygy cycles and Jupiter’s orbital period respectively. Leif Svalgaard vehemently denied this correlation when I pointed it out to him a few years ago.

rob-wilson-bimodal-sun

The same correlation was noted by independent researcher Timo Niroma in 1989, who conducted his own survey and analysis of solar cycle lengths. He produced this simple ascii-art graphic to present his results.

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Exoplanet analysis is a growing field of scientific study as data pours in from the likes of NASA’s successful Kepler probe.

The abstract of a new paper explains its focus on this data:
‘Mean motion resonances and near-resonances up to the outer/inner orbital period ratio’s value of 5 and the denominator 4 are tested for all adjacent exoplanet orbits.’

Without delving into the nuts and bolts of the analysis here, let’s look at the list of results (click on image to view details):

By Marian C. Ghilea (2015)

By Marian C. Ghilea (2015)

The column ‘resonance type’ shows the planet:planet ratios we’re interested in.
Clearly there are many examples, although ‘near resonances’ are also included.

From the author’s concluding remarks:
‘Performing a simple analysis, the resonance or near-resonance states present in all the multiplanetary systems known to date can be found numerically using a computer analysis tool.’

‘The first results, presented in this paper, suggest different resonance or near-resonance distributions for different planet categories. The resonance/near resonance numbers of 2/1 and 3/2 appear to be dominant for the planets with larger masses while the 5/3 resonance seems to be the most common for terrestrial planets and mini neptunes. For giant planets, the 2/1 resonances are dominating at larger distances from the host star while the 3/2 resonance is more common at close distances from it. Resonances for values higher than 5/2 are encountered
only for planets with masses larger than 10 (ME*)’ [*Earth masses].

We can see from this that these ‘near resonances’ crop up regularly in exoplanet systems just as they do in our solar system e.g. Jupiter-Saturn 5:2, Neptune-Pluto 3:2.

Whatever the mechanism(s) involved, the frequency of their appearance can’t be regarded as accidental.

***
See also the Wikipedia page on orbital resonance

H/T Oldbrew.

Golden rings of star formation

NGC 3081 is seen here nearly face-on. Compared to other spiral galaxies, it looks a little different. The galaxy’s barred spiral centre is surrounded by a bright loop known as a resonance ring. This ring is full of bright clusters and bursts of new star formation.

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Kepler Space Telescope [NASA]

Kepler Space Telescope [NASA]


A very interesting report of a new science paper has appeared in the New Scientist:

‘William Ditto and his colleagues at the University of Hawaii, Manoa, compared the two strongest oscillations, or tones, made by the variable star KIC 5520878, using observations by NASA’s Kepler space telescope. They noticed that dividing the frequency of the secondary note by that of the primary, or lowest, note gives a value near the “golden ratio” – a number that shows up often in art and nature and is close to 1.618′

So is it real or did they perhaps just imagine it?
Let’s start with the abstract :

‘The unprecedented light curves of the Kepler space telescope document how the brightness of some stars pulsates at primary and secondary frequencies whose ratios are near the golden mean, the most irrational number.’

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From Space.com. It’s worth reading between the lines of this one to see the perplexed furrows on the brows of the ‘surprised’  scientists.

dynamoThe magnetic fields of planetary building blocks lasted for a surprisingly long time in the solar system’s early days, a new study suggests.

The magnetic fields of these big asteroids were apparently generated by the same process that drives Earth’s global magnetic activity, and could have persisted for hundreds of millions of years after the objects’ formation, researchers said.
The study team analyzed pallasites, iron-and-nickel meteorites believed to originate from an ancient rocky body about 250 miles (400 kilometers) wide. The pallasites contain tiny particles of ‪tetrataenite — a mineral that records a magnetic history of the parent body going back billions of years.

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Solar system cartoon [NASA]

Solar system cartoon [NASA]

This is not a new idea but it seems to be gaining a bit more traction. Planetary bodies like Pluto-sized Sedna don’t seem to fit the accepted ‘rules’ of solar system dynamics.

Phys.org reports: There could be at least two unknown planets hidden well beyond Pluto, whose gravitational influence determines the orbits and strange distribution of objects observed beyond Neptune. This has been revealed by numerical calculations made by researchers at the Complutense University of Madrid and the University of Cambridge. If confirmed, this hypothesis would revolutionise solar system models.

Astronomers have spent decades debating whether some dark trans-Plutonian planet remains to be discovered within the solar system. According to the calculations of scientists at the Complutense University of Madrid (UCM, Spain) and the University of Cambridge (United Kingdom) not only one, but at least two planets must exist to explain the orbital behaviour of extreme trans-Neptunian objects (ETNO).
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Solar contiguous activity cycle 23/24

Posted: December 20, 2014 by tchannon in Astrophysics, Solar physics

At first sight this Brazilan paper in Astronomy & Astrophysics is relatively uninteresting if you are familar with sunspot activity, appears to be another general look using waveletts.

Two features strike me as worthy of highlighting

  • a double burst of activity during cycle 23, not obvious from sunspot data alone
  • continuing activity right through the 23/24 transition

Image

Extract from paper Fig. 5, my highlight of strong X activity post the cycle 23 sunspot peak.

Wavelet analysis of CME, X-ray flare, and sunspot series

M. R. G. Guedes, E. S. Pereira and J. R. Cecatto

A&A 573 A64 (2015)

DOI: http://dx.doi.org/10.1051/0004-6361/201323080

(access with registration, large PDF 17.7MB)

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Guest post from Peter Morecambe aka ‘Galloping Camel’

CLIMATE SCIENCE

The Kyoto Protocol

Elites around the world tend to believe that rising levels of CO2 in our atmosphere will cause catastrophic climate changes. Collectively they wield enough power to shape energy policies in many nations according to commitments laid down in the “Kyoto Protocol” and subsequent accords. It is interesting to compare the fate of the Kyoto Protocol based on the work of “Climate Scientists” such as Michael Mann with that of the Montreal Protocol based on the work of people like McElroy.

The Montreal Protocol essentially banned the production of Freon and similar compounds based on the prediction that this would reduce the size of the polar “Ozone Holes”. After the ban went into effect the size of the ozone holes diminished. This may mean that the science presented by McElroy and his cohorts was “Robust” or it may be dumb luck. Either way, McElroy has credibility and “Skeptics” are ridiculed. The Kyoto Protocol did not fare so well.

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venus-transit-2012Congratulations to Astrophysicist Ian Wilson who has had a new paper published at Pattern Recognition in Physics:
Discussion of this paper is going to be in the form of a workshop with specific objectives, and comments will be strictly moderated for relevance. The objectives will be announced by the main participants, Ian Wilson and Paul Vaughan, in their opening comments. Basically, unless you have something to contribute to the mathematical exposition, please sit this one out and watch.

This new peer-reviewed paper is available for (free) download at: http://www.pattern-recognition-in-physics.com/pub/prp-2-75-2014.pdf . This post reproduces the one at Ian’s blog.

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By Kelly Dickerson for Yahoo News:

ESA-Magnetospheres_600_MThe sun may be partly responsible for lightning strikes on Earth, and scientists think fluctuations in the sun’s magnetic field could be used to predict lightning storms weeks in advance.

The sun’s magnetic field can bend Earth’s own magnetic field, and this twisting and turning may be allowing an influx of high-energy particles into the planet’s atmosphere. These particles can cause a buildup of electric charge that can trigger lightning strikes.

From 2001 to 2006, during a period when the sun’s magnetic field was severely skewing the Earth’s magnetic field, the United Kingdom saw 50 percent more lightning strikes than normal, according to the new study. This severe skewing happens regularly as the sun’s magnetic field shifts. Scientists say this suggests the sun’s magnetic field could be used to predict the occurrence of lightning.

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saturn2From New Scientist:

Earth’s comfortable temperatures may be thanks to Saturn’s good behaviour. If the ringed giant’s orbit had been slightly different, Earth’s orbit could have been wildly elongated, like that of a long-period comet.

Our solar system is a tidy sort of place: planetary orbits here tend to be circular and lie in the same plane, unlike the highly eccentric orbits of many exoplanets. Elke Pilat-Lohinger of the University of Vienna, Austria, was interested in the idea that the combined influence of Jupiter and Saturn – the solar system’s heavyweights – could have shaped other planets’ orbits. She used computer models to study how changing the orbits of these two giant planets might affect the Earth.

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Writing from Australia Ian Wilson will be familiar to Talkshop regulars expounding his interest in astronomical connections with earth. He has three related recent articles and now a summary binding them together. Tim adds, the subject has a long history including false accusations of astrology by detractors; in this linked 1999 paper by a veteran scientist some of the origins and history is briefly mentioned and also that as data and computing power becomes available progress is being made. It mentions El Nino [paper see ref 1].  Strangers may need to get a conceptual understanding of the regular alignment of the earth moon and sun, where self evident effect on earth is the cyclic variation is ocean tidal height.

Over to Ian

1. A SUMMARY OF THE THREE PREVIOUS POSTS

If you are unfamiliar with this topic you may wish to read the following three post in order to understand this current covering post.

Observations of the Earth rate of spin (i.e. LOD) show that there are abrupt decreases in the Earth’s rotation rate of the order of a millisecond that take place roughly once every 13.7 days. These slow downs in spin occur whenever the oceanic (and atmospheric) tidal bulge is dragged across the Earth’s equator by the Moon. They are produced by the conservation of total angular momentum of the Earth, its oceans and its atmosphere.

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Exceptionally detailed image of a young star 450 light years away reveals detail of proto-planetary disc with gaps. :

This image compares the size of the Solar System with HL Tauri and its surrounding protoplanetary disc. Although the star is much smaller than the Sun, the disc around HL Tauri stretches out to almost three times as far from the star as Neptune is from the Sun.

This image compares the size of the Solar System with HL Tauri and its surrounding protoplanetary disc. Although the star is much smaller than the Sun, the disc around HL Tauri stretches out to almost three times as far from the star as Neptune is from the Sun.

HL Tauri — a young star, about 450 light-years away, which is surrounded by a dusty disc [1]. The resulting image exceeds all expectations and reveals unexpectedly fine detail in the disc of material left over from star birth. It shows a series of concentric bright rings, separated by gaps [2].

“These features are almost certainly the result of young planet-like bodies that are being formed in the disc. This is surprising since such young stars are not expected to have large planetary bodies capable of producing the structures we see in this image,” said Stuartt Corder, ALMA Deputy Director.

When we first saw this image we were astounded at the spectacular level of detail. HL Tauri is no more than a million years old, yet already its disc appears to be full of forming planets. This one image alone will revolutionise theories of planet formation,” explained Catherine Vlahakis, ALMA Deputy Program Scientist and Lead Program Scientist for the ALMA Long Baseline Campaign.

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Michele left a comment on suggestions but the surprise came later

Big Ar 2192 and flare X1.1 + CME

Image

Note the Solex date: 14th October 2014, today is the 19th.

I looked at the Spaceweather archive for the 14th and of course the authors did not know what was about to happen

SOLAR SECTOR BOUNDARY CROSSING: High-latitude auroras are possible on Oct. 14th when Earth crosses through a fold in the heliospheric current sheet. This is called a “solar sector boundary crossing,” and NOAA forecasters estimate a 25% chance of polar geomagnetic storms when it occurs.

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The size of the sun is of critical importance to solar studies yet this is poorly known, let alone if and how the size varies over time. Paper published this week in Astronomy & Astrophysics.

Image

Fig.1. Left: solar radius measurements (red symbols) made since the seventeenth century (Rozelot & Damiani 2012). The mean value of all these measurements is close to 960 arcsec. Right: focus on solar radius measurements made since 1970. …

Fig.2. Evolution of the solar radius variations over time for ground instruments (Solar Astrolabe, DORAYSOL and SODISMII monthly mean at 782.2 nm), balloon experiment (SDS), and space instrument (MDI) vs. daily sunspot number time-series. For each series, the mean has been taken as reference value.

Fig.2. Evolution of the solar radius variations over time for ground instruments (Solar Astrolabe, DORAYSOL and SODISMII monthly mean at 782.2 nm), balloon experiment (SDS), and space instrument (MDI) vs. daily sunspot number time-series. For each series, the mean has been
taken as reference value.

 

Ground-based measurements of the solar diameter during the rising phase of solar cycle 24
M. Meftah, T. Corbard, A. Irbah, R. Ikhlef, F. Morand, C. Renaud, A. Hauchecorne, P. Assus, J. Borgnino, B. Chauvineau, M. Crepel, F. Dalaudier, L. Damé, D. Djafer, M. Fodil, P. Lesueur, G. Poiet, M. Rouzé, A. Sarkissian, A.Ziad, and F. Laclare

Paper access is available with registration.

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The Talkshop has an interest in orbital periods, spin-orbit coupling, the equalisation by nature of the gaps between objects.

Image

Rotational properties of the binary and non-binary populations
in the trans-Neptunian belt
A. Thirouin, K. S. Noll. J. L. Ortiz, and N. Morales
Published online 8th Sept 2014
Astronomy & Astrophysics (early access on registration)
http://dx.doi.org/10.1051/0004-6361/201423567

Abstract

We present results for the short-term variability of binary trans-Neptunian objects (BTNOs). …

A second older paper may be of interest

Image

 

CHARACTERIZATION OF SEVEN ULTRA-WIDE TRANS-NEPTUNIAN BINARIES
Alex H. Parker, JJ Kavelaars, Jean-Marc Petit, Lynne Jones, Brett Gladman, Joel Parker
Version 2 published late 2011
The Astrophysical Journal, open access copy, http://arxiv.org/abs/1108.2505v2
http://dx.doi.org/10.1088/0004-637X/743/1/1

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