Abstract
The cosmic origin of elements heavier than iron has long been uncertain. Theoretical modelling1,2,3,4,5,6,7 shows that the matter that is expelled in the violent merger of two neutron stars can assemble into heavy elements such as gold and platinum in a process known as rapid neutron capture (r-process) nucleosynthesis. The radioactive decay of isotopes of the heavy elements is predicted8,9,10,11,12 to power a distinctive thermal glow (a ‘kilonova’). The discovery of an electromagnetic counterpart to the gravitational-wave source13 GW170817 represents the first opportunity to detect and scrutinize a sample of freshly synthesized r-process elements14,15,16,17,18. Here we report models that predict the electromagnetic emission of kilonovae in detail and enable the mass, velocity and composition of ejecta to be derived from observations. We compare the models to the optical and infrared radiation associated with the GW170817 event to argue that the observed source is a kilonova. We infer the presence of two distinct components of ejecta, one composed primarily of light (atomic mass number less than 140) and one of heavy (atomic mass number greater than 140) r-process elements. The ejected mass and a merger rate inferred from GW170817 imply that such mergers are a dominant mode of r-process production in the Universe.
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Acknowledgements
D.K. is supported in part by a Department of Energy (DOE) Office early career award DE-SC0008067, a DOE Office of Nuclear Physics award DE-SC0017616, and by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, Divisions of Nuclear Physics, of the US DOE under contract number DE-AC02-05CH11231. This work was supported in part by the DOE SciDAC award DE-SC0018297. E.R.-R. acknowledges support from a Niels Bohr Professorship funded by DNRF, and support from UCMEXUS, the David and Lucile Packard Foundation. This research is funded in part by the Gordon and Betty Moore Foundation through grant GBMF5076. E.Q. was funded in part by the Simons Foundation through a Simons Investigator Award. J.B. is supported by the National Aeronautics and Space Administration (NASA) through the Einstein Fellowship Program, grant number PF7-180162, issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the US DOE under contract number DE AC02-05CH11231. J.B. is an Einstein Fellow.
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D.K. carried out the model calculations and analysis and led the writing of the manuscript. B.M. helped with the text, aided in the theoretical interpretation, and contributed to the schematic figure of mass ejection. J.B. carried out multi-dimensional radiation transport calculations to estimate the effects of asymmetry on the light curves. E.Q. provided theoretical interpretations and aided in the writing of the manuscript. E.R.-R. provided theoretical input and estimates of the contribution of mergers to the r-process in the Galaxy.
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Extended data figures and tables
Extended Data Figure 1 Dependence of model light curves on the ejecta density profile and compositional stratification.
The models all have mass M = 0.025M⊙ and velocity vk = 0.25c. a, Comparison of models with a homogenous composition to one where the lanthanide mass fraction varies from Xlan = 10−6 at the outer ejecta edge to Xlan = 10−4 in the interior (see equation (7)). b, Comparison of models with different density gradient in the outer layers. A shallower exponent (n < 10) leads to a cooler photosphere and suppresses the early ultraviolet and blue emission. The light curves at times t ≥ 1 d and in redder bands are essentially independent of the outer density profile.
Extended Data Figure 2 Multi-dimensional models demonstrating the orientation dependence of asymmetric kilonova light curves.
a, Bolometric light curves of light r-process ejecta (with M = 0.025M⊙, vk = 0.15c and Xlan = 10−5) distributed in a conical polar region of opening half angle 45°. b, Bolometric light curves of an oblate ellipsoidal distribution of heavy r-process ejecta (with M = 0.04M⊙, vk = 0.1c and Xlan = 10−2) with an axis ratio of a = 4. The orientation effects lead to modest variations in the peak brightness. However, these models do not account for both a polar and an ellipsoidal component being present and influencing each other.
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Kasen, D., Metzger, B., Barnes, J. et al. Origin of the heavy elements in binary neutron-star mergers from a gravitational-wave event. Nature 551, 80–84 (2017). https://doi.org/10.1038/nature24453
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Please be aware that LIGO's calculations are wrong because Einstein's relativity theory has already been disproved both logically and experimentally (see "Challenge to the special theory of relativity", March 1, 2016 on Physics Essays and a press release "Special Theory of Relativity Has Been Disproved Theoretically" on Eurekalert website: https://www.eurekalert.org/... ). The problem of Einstein's relativity is that it has redefined time and space through Lorentz Transformation. The newly defined time is no longer the physical time measured with physical clocks, which can be easily demonstrated by the following thought experiment of candle clocks:
There are a series of vertically standing candles with the same burning rate and moving at different constant horizontal velocities in an inertial reference frame of (x, y, z, t) where x, y, z, t are relativistic positions and time. At any moment t of relativistic time, all candles have the same height H in the reference frame of (x, y, z, t) and the height has been calibrated to physical time as physical clocks. Therefore, we have the simultaneous events of the observation measured in both relativistic time and physical time in the frame of (x, y, z, t): (Candle1, x1, y1, H, t), (candle2, x2, y2, H, t), ?, (CandleN, xN, yN, H, t). When these events are observed on anther horizontally moving inertial reference frame (x', y', z', t'), according to special relativity, these events in the reference frame of (x', y', z', t') can be obtained through Lorentz Transformation: (Candle1, x'1, y'1, H, t'1), (Candle2, x'2, y'2, H, t'2), ? , (CandleN, x'N, y'N, H, t'N) where t'1, t'2, ?, and t'Nਊre relativistic times of the events in the frame of (x', y', z', t'). It is seen that these events have different relativistic times after Lorentz Transformation in the frame of (x', y', z', t'), i.e., they are no longer simultaneous measured with relativistic time in the frame of (x', y', z', t'), but the heights of the candles remain the same because the vertical heights here do not experience any Lorentz contraction. Since the heights of the candles are the measures of the physical time, we can see these events still have the same physical time, i.e., they are still simultaneous measured with the physical time. Therefore, the physical time is invariant of inertial reference frames, which is different from relativistic time. As relativistic time is no longer the physical time we measure with physical devices, the des cription of special relativity is irrelevant to the physical world.
Now let's have a look at the symmetric twin paradox. Two twins made separate space travels in the same velocity and acceleration relative to the earth all the time during their entire trips but in opposite directions. According to special relativity, each twin should find the other twin?s clock ticking more slowly than his own clock during the entire trip due to the relative velocity between them because acceleration did not have any effect on kinematic time dilation in special relativity. But when they came back to the earth, they found their clocks had exact the same time because of symmetry. Thus, there is a contradiction which has disproved special relativity. This thought experiment demonstrates that relativistic time is not our physical time and can never be materialized on physical clocks.
Now let's look at clocks on the GPS satellites which is thought as one of the strong evidences of Einstein's relativity. Many physicists claim that clocks on the GPS satellites are corrected according to both special relativity and general relativity. This is not true because the corrections of the atomic clocks on the GPS satellites are absolute changes of the clocks (i.e. the same observed in all reference frames), none of which is relative to a specific observer as claimed by special relativity. After all corrections, the clocks are synchronized not only relative to the ground clocks but also relative to each other, i.e., time is absolute and special relativity is wrong.
This is a fact as shown on Wikipedia. But some people still argue that the clocks on the GPS satellites are only synchronized in the earth centered inertial reference frame, and are not synchronized in the reference frames of the GPS satellites. If it were true, then the time difference between a clock on a GPS satellite and a clock on the ground observed in the satellite reference frame would monotonically grow due to their relative velocity while the same clocks observed on the earth centered reference frame were still synchronized. If you corrected the clock on the satellite when the difference became significant, the correction would break the synchronization of the clocks observed in the earth centered frame. That is, there is no way to make such a correction without breaking the synchronization of the clocks observed in the earth centered frame. Therefore, it is wrong to think that the clocks are not synchronized in the satellite frame.
Hefele-Keating experiment is also considered as another evidence of relativistic effects. It is clear that all the differences of the clocks after flights in Hefele-Keating experiment were absolute (i.e., they were the same no matter whether you observe them on the earth, on the moon or on the space station). But according to relativity, if the clocks were observed on the earth, the two clocks after flights had experienced the equivalent paths of same velocity and same distance in same elevation, and thus should generate the same kinematic time dilation and the same gravitational time dilation, directly contradicting the experimental result. Therefore, the differences of the clocks were nothing to do with the velocities relative to each other or relative to the earth as claimed by relativists, but were the result of the velocities relative to one medium which seems fully dragged by the earth on its surface but partially dragged on the altitude of the airplanes. It is wrong to interpret the differences of the displayed times of the clocks as the results of relativistic effects.
Experiments show that electrons will emit photons when they are "moving", but ?moving? is relative. All electrons on the earth can be considered "moving" when you observe them on a rocket. According to special relativity, you should see them emit photons. Why in a rocket frame don't you see the electrons emit photons? It is because special relativity is wrong. It is not the velocity relative to the observer which makes an electron emit photons, but it is the velocity relative to ?something? makes an electron emit photons. This ?something? is aether, the existence of which has been proved in the above paper. Photons are waves of aether which is a compressible viscous fluid filling up the entire visible part of the universe, though its viscosity is very very small. It is the velocity relative to aether makes an electron emit photons, just as a boat on a water generates waves only when it moves relative to the water.
The increase of the lives of muons in particle accelerators or going through the atmosphere are the effects of aether caused by their velocities relative to aether, which are absolute changes and the same observed in all reference frames, nothing to do with relativity.
All so-called proofs of relativistic effects are just misinterpretations of experiments and observations without exception, and all what relativity describes is irrelevant to physical phenomena, including the speed of light which in special relativity is constant in all inertial reference frames, but which in real physical world still follows Newton's velocity addition formula (see the paper).
That is, time is absolute and space is 3D Euclidean. There is nothing called spacetime continuum in nature, not to mention the ripples of spacetime.