scholarly journals Launch of a CME-associated eruptive prominence as observed with IRIS and ancillary instruments

2019 ◽  
Vol 624 ◽  
pp. A72 ◽  
Author(s):  
P. Zhang ◽  
É. Buchlin ◽  
J.-C. Vial
Keyword(s):  
Total Mass ◽  
Observation Time ◽  
The Sun ◽  
Ionization Degree ◽  
Eruptive Prominence ◽  
Physical Conditions ◽  
Optical Flow Method ◽  
Order Of Magnitude ◽  
The Masses ◽  
Hydrogen Mass

Aims. In this paper we focus on the possible observational signatures of the processes which have been put forward for explaining eruptive prominences. We also try to understand the variations in the physical conditions of eruptive prominences and estimate the masses leaving the Sun versus the masses returning to the Sun during eruptive prominences. Methods. As far as velocities are concerned, we combined an optical flow method on the Atmospheric Imaging Assembly (AIA) 304 Å and Interface Region Imaging Spectrograph (IRIS). Mg II h&k observations in order to derive the plane-of-sky velocities in the prominence, and a Doppler technique on the IRIS Mg II h&k profiles to compute the line-of-sight velocities. As far as densities are concerned, we compared the absolute observed intensities with values derived from non-local thermodynamic equilibrium radiative transfer computations to derive the total (hydrogen) density and consequently compute the mass flows. Results. The derived electron densities range from 1.3 × 109 to 6.0 × 1010 cm−3 and the derived total hydrogen densities range from 1.5 × 109 to 2.4 × 1011 cm−3 in different regions of the prominence. The mean temperature is around 1.1 × 104 K, which is higher than in quiescent prominences. The ionization degree is in the range of 0.1–10. The total (hydrogen) mass is in the range of 1.3 × 1014–3.2 × 1014 g. The total mass drainage from the prominence to the solar surface during the whole observation time of IRIS is about one order of magnitude smaller than the total mass of the prominence.

Closing remarks: astronomical

1990 ◽  
Vol 330 (1615) ◽  
pp. 683-684 ◽  
Keyword(s):  
Solar Activity ◽  
Decisive Role ◽  
The Sun ◽  
Physical Conditions ◽  
Dust Clouds ◽  
The Galaxy ◽  
Order Of Magnitude ◽  
Earth’S Climate ◽  
Life On Earth ◽  
Physical And Chemical

Over the past two days, we have covered many facets of the basic interactions between the solar activity and the Earth’s climate. As an astronomer, I should perhaps first comment on the fact that solar activity is not the only astronomical or astrophysical phenomenon to influence physical conditions in the biosphere. Over a very long timescale of thousands of millions of years the evolution of the Sun from a pre-main-sequence star to a star of G type has not only fundamentally controlled the physical and chemical processes in the formation of the planets but has controlled their surface physical characteristics. Over timescales an order of magnitude less, the location of the Solar System in the Galaxy may have influenced life on Earth. For example it has been noted that when the Sun crossed the spiral arms of the Galaxy and their dense dust clouds, some catastrophies might have resulted; the disappearance of the dinosaurs could be accounted for by such phenomena, as was once suggested by Sir William McCrea, F.R.S.; but nearby supernovae, grazing comets, and on large meteorites might very well have played a decisive role in the evolution of species and of our Earth. On a smaller timescale, a million years, the variation in solar energy falling on the Earth, due to secular changes in the terrestrial orbit parameters (Milankovitch-Berger theories), would have caused climatic changes and have been shown to account for the successive ice ages of the Quaternary. While bearing this in mind the role of solar activity on the timescale of recent millennia, but also on shorter timescales, is of obvious importance to society and, as we have seen in this meeting, is only now being properly investigated.

scholarly journals 13 Years of Storms: An Analysis of the Effects of Storms on Lake Physics on the Atlantic Fringe of Europe

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 318 ◽  
Author(s):  
Mikkel René Andersen ◽  
Elvira de Eyto ◽  
Mary Dillane ◽  
Russell Poole ◽  
Eleanor Jennings
Keyword(s):  
Water Column ◽  
Western Europe ◽  
Thermal Structure ◽  
Winter Storms ◽  
Water Column Stability ◽  
Physical Conditions ◽  
Order Of Magnitude ◽  
Storm Frequency ◽  
Summer Storm ◽  
Lake Physics

While winter storms are generally common in western Europe, the rarer summer storms may result in more pronounced impacts on lake physics. Using long-term, high frequency datasets of weather and lake thermal structure from the west of Ireland (2005 to 2017), we quantified the effects of storms on the physical conditions in a monomictic, deep lake close to the Atlantic Ocean. We analysed a total of 227 storms during the stratified (May to September, n = 51) and non-stratified (November to March, n = 176) periods. In winter, as might be expected, changes were distributed over the entire water column, whereas in summer, when the lake was stratified, storms only impacted the smaller volume above the thermocline. During an average summer (May–September) storm, the lake number dropped by an order of magnitude, the thermocline deepened by an average of 2.8 m, water column stability decreased by an average of 60.4 j m−2 and the epilimnion temperature decreased by a factor of five compared to the average change in winter (0.5 °C vs. 0.1 °C). Projected increases in summer storm frequency will have important implications for lake physics and biological pathways.

scholarly journals Hot and cold running water: understanding evolved star winds

2017 ◽  
Vol 13 (S336) ◽  
pp. 347-350
Author(s):  
A. M. S. Richards ◽  
M. D. Gray ◽  
A. Baudry ◽  
E. M. L. Humphreys ◽  
S. Etoka ◽  
...  
Keyword(s):  
Mass Loss ◽  
Circumstellar Envelope ◽  
Number Density ◽  
Running Water ◽  
Physical Conditions ◽  
Evolved Stars ◽  
Order Of Magnitude ◽  
Homogeneous Regions ◽  
Maser Sources

AbstractOutstanding problems concerning mass-loss from evolved stars include initial wind acceleration and what determines the clumping scale. Reconstructing physical conditions from maser data has been highly uncertain due to the exponential amplification. ALMA and e-MERLIN now provide image cubes for five H2O maser transitions around VY CMa, at spatial resolutions comparable to the size of individual clouds or better, covering excitation states from 204 to 2360 K. We use the model of Gray et al. 2016, to constrain variations of number density and temperature on scales of a few au, an order of magnitude finer than is possible with thermal lines, comparable to individual cloud sizes or locally almost homogeneous regions. We compare results with the models of Decin et al. 2006 and Matsuura et al. 2014 for the circumstellar envelope of VY CMa; in later work this will be extended to other maser sources.

scholarly journals Suggestion as to the Cause of the Earth's Internal Heat

1904 ◽  
Vol 24 ◽  
pp. 415-422
Author(s):  
George Romanes
Keyword(s):  
Internal Heat ◽  
The Sun ◽  
Fluid Mass ◽  
The Earth ◽  
Sufficient Cause ◽  
Heated Fluid ◽  
The Masses ◽  
Gravitational Compression

During the discussions that have arisen as to the internal heat of the earth, the writer has never seen any reason given for supposing that there was a time when the earth was a highly heated fluid mass, and he believes that view to have originated by analogy from the case of the sun; and no other cause of the heat seems to be generally assumed than the collisions of the parts that came together to form the earth's mass. He has expected to find some one maintaining that gradual gravitational compression of the mass was the main source of the earth's internal heat, but till recently he has never tried to find out if it could possibly be a sufficient cause. It has always seemed to him that the formation of the earth's mass must have been accomplished under circumstances so different from the case of the sun that an analogy could scarcely be drawn between the two cases; indeed, it is obvious that the amount of heat produced by the formation of planets from nebulae will depend principally on their masses, and will be in a, higher ratio than that of the masses.

scholarly journals 42. Solar cosmic radiation and the interstellar magnetic field

1958 ◽  
Vol 6 ◽  
pp. 404-419 ◽  
Author(s):  
A. Ehmert
Keyword(s):  
Magnetic Field ◽  
Solar Radiation ◽  
Cosmic Radiation ◽  
The Sun ◽  
High Latitudes ◽  
Narrow Angle ◽  
The Earth ◽  
Order Of Magnitude ◽  
The Impact ◽  
Impact Zones

The increase of cosmic radiation on 23 February 1956 by solar radiation exhibited in the first minutes a high peak at European stations that were lying in direct impact zones for particles coming from a narrow angle near the sun, whilst other stations received no radiation for a further time of 10 minutes and more. An hour later all stations in intermediate and high latitudes recorded solar radiation in a distribution as would be expected if this radiation fell into the geomagnetic field in a fairly isotropic distribution. The intensity of the solar component decreased at this time at all stations according to the same hyperbolic law (~t–2).It is shown, that this decreasing law, as well as the increase of the impact zones on the earth, can be understood as the consequence of an interstellar magnetic field in which the particles were running and bent after their ejection from the sun.Considering the bending in the earth's magnetic field, one can estimate the direction of this field from the times of the very beginning of the increase in Japan and at high latitudes. The lines of magnetic force come to the earth from a point with astronomical co-ordinates near 12·00, 30° N. This implies that within the low accuracy they have the direction of the galactic spiral arm in which we live. The field strength comes out to be about 0·7 × 10–6gauss. There is a close agreement with the field, that Fermi and Chandrasekhar have derived from Hiltner's measurements of the polarization of starlight and the strength of which they had estimated to the same order of magnitude.

scholarly journals From Planetary Nebula nuclei to white dwarfs: The impact of evolutionary envelope masses

1997 ◽  
Vol 180 ◽  
pp. 389-389 ◽  
Author(s):  
T. Blöcker ◽  
F. Herwig ◽  
T. Driebe ◽  
H. Bramkamp ◽  
D. Schönberner
Keyword(s):  
Planetary Nebula ◽  
Total Mass ◽  
White Dwarfs ◽  
Stellar Mass ◽  
Asymptotic Giant Branch ◽  
The Masses ◽  
The Impact

It is well known that the evolution of white dwarfs (WDs) depends sensitively on the question whether they have “thin” or “thick” envelopes of H and He (see Wood 1995). Standard evolutionary caluclations (e.g. Paczynksi 1971) show that at the tip of the Asymptotic Giant Branch the envelope masses are tightly correlated with the mass of the hydrogen exhausted core (≈ total mass). Accordingly, the masses of hydrogen, MH, and helium, MHe, on top of the degenerate C/O interiors decrease by orders of magnitudes with increasing stellar mass. In contrast, many applications of WD calculations consider only single values of qH,He = log(MH,He/M∗) asuming either “thick” or “thin” envelopes.

The work of Nicolaus Copernicus

1974 ◽  
Vol 336 (1604) ◽  
pp. 105-114 ◽  
Keyword(s):  
Solar System ◽  
Major Axis ◽  
The Sun ◽  
Circular Model ◽  
Popular View ◽  
Order Of Magnitude ◽  
Nicolaus Copernicus

It is commonly supposed that Copernicus placed the Sun at the centre of the solar system, letting the planets move around the Sun in simple circles, thereby recovering the theory of Aristarchus of Samos. This popular view is quite wrong, as it will be the purpose of this lecture to show. The six planets known to Copernicus have the eccentricity values given in the following table: planet eccentricity major-axis (in terms of Earth) Mercury 0.2056 0.387 Venus 0.0068 0.723 Earth 0.0167 1.000 Mars 0.0933 1.524 Jupiter 0.0484 5.203 Saturn 0.0558 9.539 The departures from simple circles are particularly serious for Mercury and Mars. If the eccentricity is ignored for these planets it will be found that the predictions of a simple circular model are in very serious disagreement with observation. The errors for Mars in the worst circumstances would be more than 15°, errors so gross as to have been unacceptable to astronomers even 1500 years before Copernicus. Ptolemy, working between A. D. 100 and 150, developed a geocentric theory which reduced the discrepancies by more than an order of magnitude - in the case of Mars, from more than 15° to about 1°. It was this far more sophisticated theory of Ptolemy which Copernicus had to match in his heliocentric theory.

scholarly journals Magnitude and frequency of landslides triggered by a storm event, Loughborough Inlet, British Columbia

2004 ◽  
Vol 4 (3) ◽  
pp. 475-483 ◽  
Author(s):  
R. H. Guthrie ◽  
S. G. Evans
Keyword(s):  
British Columbia ◽  
Power Law ◽  
Storm Event ◽  
Data Sets ◽  
Landslide Occurrence ◽  
Physical Conditions ◽  
Pareto Model ◽  
Order Of Magnitude ◽  
Storm Cells ◽  
Coastal British Columbia

Abstract. One hundred and one landslides were documented across 370km2 following a rainstorm that swept the British Columbia coastline on 18 November 2001. Despite the regional nature of the storm, the landslides were spaced close together, even within the study area. Landslide clustering is attributed to high intensity storm cells too small to be recorded by the general hydrometric network. The evidence nicely corroborates previous historical studies that reached similar conclusions, but against which there was no modern analog analyzed for coastal British Columbia. Magnitude-cumulative frequency data plotted well on a power law curve for landslides greater than 10000m2, however, below that size several curves would fit. The rollover effect, a point where the data is no longer represented by the power law, therefore occurs at about 1.5 orders of magnitude higher than the smallest landslide. Additional work on Vancouver Island has provided evidence for rollovers at similar values. We propose that the rollover is a manifestation of the physical conditions of landslide occurrence and process uniformity. The data was fit to a double Pareto distribution and P-P plots were generated for several data sets to examine the fit of that model. The double Pareto model describes the bulk of the data well, however, less well at the tails. For small landslides (<650m2) this may still be a product of censoring. Landscape denudation from the storm was averaged over the study area and equal to 2mm of erosion. This is more than an order of magnitude larger than the annual rate of denudation reported by other authors for coastal British Columbia, but substantially less than New Zealand. The number is somewhat affected by the rather arbitrary choice of a study area boundary.

scholarly journals Mass-correlated rotational Raman spectra with high resolution, broad bandwidth, and absolute frequency accuracy

2018 ◽  
Vol 115 (20) ◽  
pp. 5072-5076 ◽  
Author(s):  
Christian Schröter ◽  
Jong Chan Lee ◽  
Thomas Schultz
Keyword(s):  
Raman Spectra ◽  
Optical Excitation ◽  
Rotational Transition ◽  
Observation Time ◽  
Absolute Frequency ◽  
Naturally Occurring ◽  
Order Of Magnitude ◽  
Quantum Wave ◽  
External Clock ◽  
Time And Energy

We present mass-correlated rotational alignment spectroscopy, based on the optical excitation of a coherent rotational quantum wave and the observation of temporal wave interferences in a mass spectrometer. Combined electronic and opto-mechanical delays increased the observation time and energy resolution by an order of magnitude compared with preceding time-domain measurements. Rotational transition frequencies were referenced to an external clock for accurate absolute frequency measurements. Rotational Raman spectra for six naturally occurring carbon disulfide isotopologues were resolved with 3 MHz resolution over a spectral range of 500 GHz. Rotational constants were determined with single-kilohertz accuracy, competitive with state-of-the-art frequency domain measurements.

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