We present updated standard solar models (SSMs) that incorporate the latest results for nuclear fusion rates, recently published. We show helioseismic results for high and low metallicity compositions and also for an alternative set of solar abundance, derived from 3D model atmospheres, which give intermediate results. For the high and low metallicity models, we show that current solar neutrino data can not differentiate between models and that a measurement of the CNO fluxes is necessary to achieve that goal. A few additional implications of a hypothetical measurement of CNO neutrinos, both in terms of solar and stellar physics, are discussed.
When solving the solar neutrino problem on the basis of the hypothesis of the existence of a new interaction between electron neutrinos and nucleons, carried by a massless pseudoscalar boson, it becomes necessary to find the consequences of the short-term Brownian motion of neutrinos in the Sun. Earlier, we transmitted these consequences by the effective number of collisions of a neutrino with nucleons of the Sun, assuming the equality of fluxes near the Earth of left- and right-handed solar neutrinos. In this paper, we analyze the transfer of the mentioned consequences by a test geometric dis…
Measurements of the solar neutrino mass-squared difference from KamLAND and solar neutrino data are somewhat discrepant, perhaps due to nonstandard neutrino interactions in matter. We show that the zenith angle distribution of solar neutrinos at Hyper-Kamiokande and the energy spectrum of reactor antineutrinos at JUNO can conclusively confirm the discrepancy and detect new neutrino interactions.
I give an overview of the recent developments in the solar neutrino field. I focus on the Borexino detector, which has uncovered the solar neutrino spectrum below 5 MeV, providing new tests and confirmation for solar neutrino oscillations. I report on the updated measurements of the 8B solar neutrino flux by water Cherenkov and organic scintillator detectors. I review the precision measurement of the 7Be solar neutrino flux by Borexino and the search for its day-night asymmetry. I present Borexino's latest result on the study of pep and CNO neutrinos. Finally, I discuss the outstanding questio…
Solar neutrinos offer a unique opportunity to study the interaction of neutrinos with matter, a sensitive search for potential new physics effects, and a probe of solar structure and solar system formation. This paper describes the broad physics program addressed by solar neutrino studies, presents the current suite of experiments programs, and describes several potential future detectors that could address the open questions in this field. This paper is a summary of a talk presented at the Neutrino 2014 conference in Boston.
The electronic density in the Sun's inner core is inferred from the 8B, 7Be and pep neutrino flux measurements of the Super-Kamiokande, SNO and Borexino experiments. We have developed a new method in which we use the KamLAND detector determinations of the neutrino fundamental oscillation parameters: the mass difference and the vacuum oscillation angle. Our results suggest that the solar electronic density in the Sun's inner core (for a radius smaller than 10% of the solar radius) is well above the current prediction of the standard solar model, and by as much as 25%. A potential confirmation o…
The knowledge of the parameters of the solar neutrino oscillation model, provided by the SNO and Super-Kamiokande collaborations, enables us to obtain, with the Wolfenstein equation, a simple and clear analytical and numerical picture of the transformation of the neutrino state during its travel inside the Sun. We show that the resulting picture is not implicated in the characteristics of the neutrino state at the surface of the Sun and at the surface of the Earth. This circumstance with taking into account the volume distribution of solar neutrino sources indicates an obvious contradiction be…
The results of the calculation are presented for the fluxes of CN neutrinos from the Sun in case of mixing in a spherical layer in the solar core, consistent with the seismic data and with the measured solar neutrino fluxes. It is shown that a substantial increase of the flux of $^{13}N$ neutrinos can be gained in this case. The possible implications for experiment are discussed.
We determine the solar neutrino fluxes from a global analysis of the solar and terrestrial neutrino data in the framework of three-neutrino mixing. Using a Bayesian approach we reconstruct the posterior probability distribution function for the eight normalization parameters of the solar neutrino fluxes plus the relevant masses and mixing, with and without imposing the luminosity constraint. This is done by means of a Markov Chain Monte Carlo employing the Metropolis-Hastings algorithm. We also describe how these results can be applied to test the predictions of the Standard Solar Models. Our …
We present an update of the determination of the solar neutrino fluxes from a global analysis of the solar and terrestrial neutrino data in the framework of three-neutrino mixing. Using a Bayesian analysis we reconstruct the posterior probability distribution function for the eight normalization parameters of the solar neutrino fluxes plus the relevant masses and mixing, with and without imposing the luminosity constraint. We then use these results to compare the description provided by different Standard Solar Models. Our results show that, at present, both models with low and high metallicit…
Relic neutrinos from the early universe are predicted to have a relatively large number density, but extremely low energies. Hence, the only possible interaction proceeds via neutrino capture on beta-decaying nuclei. In case relic neutrinos are captured by beta-decaying nuclei in the Sun, the neutrinos normally emerging from the decay of these nuclei will be missing from the overall number of solar neutrinos registered in neutrino experiments. Within the Sun, ${}^8\mathrm{B}$ and three nuclei from the CNO cycle are found to be suitable for this kind of process. Their cross section as well as t…
The computational analyses is presented of the non stationary case with mixing of the solar model when the neutrino flux $F_{13}$ from the decay of $^{13}N$ is higher than a standard solar model predicts
Solar neutrinos coming from different nuclear reactions are now detected with a high statistics. Consequently, an accurate spectroscopic analysis of the neutrino fluxes arriving on the Earth's detectors become available, in the context of neutrino oscillations. In this work, we explore the possibility of using this information to infer the radial profile of the electronic density in the solar core. So, we discuss the constraints on the Sun's density and chemical composition that can be determined from solar neutrino observations. This approach constitutes an independent and alternative diagnos…
The first solar neutrino experiment led by Raymond Davis Jr. showed a deficit of neutrinos relative to the solar model prediction, referred to as the "solar neutrino problem" since the 1970s. The Kamiokande experiment led by Masatoshi Koshiba successfully observed solar neutrinos, as first reported in 1989. The observed flux of solar neutrinos was almost half the prediction and confirmed the solar neutrino problem. This problem was not resolved for some time due to possible uncertainties in the solar model. In 2001, it was discovered that the solar neutrino problem is due to neutrino oscillati…
The Sun's internal structure and dynamics can be studied with helioseismology, which uses the Sun's natural acoustic oscillations to build up a profile of the solar interior. We discuss how solar acoustic oscillations are affected by the Sun's magnetic field. Careful observations of these effects can be inverted to determine the variations in the structure and dynamics of the Sun's interior as the solar cycle progresses. Observed variations in the structure and dynamics can then be used to inform models of the solar dynamo, which are crucial to our understanding of how the Sun's magnetic field…
Opportunity of the solar flares (SF's) prediction observing the solar neutrino fluxes is investigated. In three neutrino generations the evolution of the neutrino flux traveling the coupled sunspots (CS's) which are the SF source is considered. It is assumed that the neutrinos possess both the dipole magnetic moment and the anapole moment while the magnetic field above the CS's may reach the values $10^5-10^6$ Gs, displays the twisting nature and has the nonpotential character. The possible resonance conversions of the solar neutrino flux are examined. Since the $ν_{eL}\to ν_{μL}$ resonance ta…
In this paper, we detail the scientific objectives and outline a strawman payload of the SOLAR sail Investigation of the Sun (SOLARIS). The science objectives are to study the 3D structure of the solar magnetic and velocity field, the variation of total solar irradiance with latitude, and the structure of the corona. We show how we can meet these science objective using solar-sail technologies currently under development. We provide a tentative mission profile considering several trade-off approaches. We also provide a tentative mass budget breakdown and a perspective for a programmatic implem…
The solar atmosphere is a hot (about 1MK), magnetised plasma of great interest to physicists. There have been many previous studies of the temperature of the Sun's atmosphere (Plowman2012, Wit2012, Hannah2012, Aschwanden2013, etc.). Almost all of these studies use the SolarSoft software package written in the commercial Interactive Data Language (IDL), which has been the standard language for solar physics. The SunPy project aims to provide an open-source library for solar physics. This work presents (to the authors' knowledge) the first study of its type to use SunPy rather than SolarSoft. Th…
Magnetic activity of the Sun and other stars causes their brightness to vary. We investigate how typical the Sun's variability is compared to other solar-like stars, i.e. those with near-solar effective temperatures and rotation periods. By combining four years of photometric observations from the Kepler space telescope with astrometric data from the Gaia spacecraft, we measure photometric variabilities of 369 solar-like stars. Most of the solar-like stars with well-determined rotation periods show higher variability than the Sun and are therefore considerably more active. These stars appear n…
We review some major, open issues in the current modelling of low and intermediate mass, main sequence stars based on seismological studies. In the present paper, the solar case is discussed together with current problems that are common to the Sun and stars with a structure similar to that of the Sun. Several additional issues specific to main sequence stars other than the Sun are reviewed and illustrated with a few stars observed with CoRoT in a companion paper.
Solar twins and analogs are fundamental in the characterization of the Sun's place in the context of stellar measurements, as they are in understanding how typical the solar properties are in its neighborhood. They are also important for representing sunlight observable in the night sky for diverse photometric and spectroscopic tasks, besides being natural candidates for harboring planetary systems similar to ours and possibly even life-bearing environments. We report a photometric and spectroscopic survey of solar twin stars within 50 pc of the Sun. Hipparcos absolute magnitudes and (B-V)_Tyc…
We present a focused parameter study of solar wind - magnetosphere interaction for the young Sun and Earth, $~3.5$ Ga ago, that relies on magnetohydrodynamic (MHD) simulations for both the solar wind and the magnetosphere. By simulating the quiescent young Sun and its wind we are able to propagate the MHD simulations up to Earth's magnetosphere and obtain a physically realistic solar forcing of it. We assess how sensitive the young solar wind is to changes in the coronal base density, sunspot placement and magnetic field strength, dipole magnetic field strength and the Sun's rotation period. F…
Magnetic activity is a global property of the Sun; the complex processes of solar activity are connected with the solar magnetic fields. For solar-type stars and the Sun magnetic activity depends on the physical parameters of the star. In this article we study the relationships between the duration of activity cycle and effective temperature for solar-type stars and the Sun. We've tried to explain these relationships due to the existence of layer of laminar convection near the bottom of the convective zone of the star. In this layer the Rossby waves are formed. They generate the primary poloid…
Motivated by the solar composition problem and by using the recently developed Linear Solar Model approach, we analyze the role of opacity and metals in the sun. After a brief discussion of the relation between the effects produced by a variation of composition and those produced by a modification of the radiative opacity, we calculate numerically the opacity kernels that, in a linear approximation, relate an arbitrary opacity variation to the corresponding modification of the solar observable properties. We use these opacity kernels to discuss the present constraints on opacity (and compositi…
Dark Matter (DM) may have a relic density that is in part determined by a particle/antiparticle asymmetry, much like baryons. If this is the case, it can accumulate in stars like the Sun to sizable number densities and annihilate to Standard Model (SM) particles including neutrinos. We show that the combination of neutrino telescope and direct detection data can be used in conjunction to determine or constrain the DM asymmetry from data. Depending on the DM mass, the current neutrino data from Super-K and IceCube give powerful constraints on asymmetric DM unless its fractional asymmetry is $\l…
We use archival daily spot coverage measurements from Howard et al. (1984) to study the rotational modulation of the Sun as though it were a distant star. A quasi-periodic Gaussian process measures the solar rotation period $P_\mathrm{rot} = 26.3 \pm 0.1$ days, and activity cycle period $P_\mathrm{cyc} = 10.7 \pm 0.3$ years. We attempt to search for evidence of differential rotation in variations of the apparent rotation period throughout the activity cycle and do not detect a clear signal of differential rotation, consistent with the null results of the hare-and-hounds exercise of Aigrain et …
The Sun is used as the fundamental standard in chemical abundance studies, thus it is important to know whether the solar abundance pattern is representative of the solar neighborhood. Albeit at low precision (0.05 - 0.10 dex) the Sun seems to be a typical solar-metallicity disk star, at high precision (0.01 dex) its abundance pattern seems abnormal when compared to solar twins. The Sun shows a deficiency of refractory elements that could be due to the formation of terrestrial planets. The formation of giant planets may also introduce a signature in the chemical composition of stars. We discus…
This article presents a comparative analysis of solar activity data, Mt Wilson diameter data, Super-Kamiokande solar neutrino data, and nuclear decay data acquired at the Lomonosov Moscow State University (LMSU). We propose that salient periodicities in all of these datasets may be attributed to r-mode oscillations. Periodicities in the solar activity data and in Super-Kamiokande solar neutrino data may be attributed to r-mode oscillations in the known tachocline, with normalized radius in the range 0.66 to 0.74, where the sidereal rotation rate is in the range 13.7 to 14.6 year-1. We propose …
The Earth's magnetosphere extension is controlled by the solar activity level via solar wind properties. Understanding such a relation in the Solar System is important for predicting also the condition of exoplanetary magnetospheres near Sun-like stars. We use measurements of a chromospheric proxy, the Ca II K index, and solar wind OMNI parameters to connect the solar activity variations, on the decennial time scales, to the solar wind properties. The data span over the time interval 1965-2021, which almost entirely covers the last 5 solar cycles. Using both cross-correlation and mutual inform…
