اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدAstro2020 Science White Paper: Synoptic Studies of the Sun as a Key to Understanding Stellar Astrospheres
55
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Ground-based solar observations provide key contextual data (i.e., the big picture) to produce a complete description of the only astrosphere we can study in situ: our Suns heliosphere. The next decade will see the beginning of operations of the Daniel K. Inouye Solar Telescope (DKIST). DKIST will join NASAs Parker Solar Probe and the NASA/ESA Solar Orbital mission, which together will study our Suns atmosphere with unprecedented detail. This white paper outlines the current paradigm for ground-based solar synoptic observations, and indicates those areas that will benefit from focused attention.
قيم البحث
اقرأ أيضاً
Interacting binaries containing white dwarfs can lead to a variety of outcomes that range from powerful thermonuclear explosions, which are important in the chemical evolution of galaxies and as cosmological distance estimators, to strong sources of
low frequency gravitational wave radiation, which makes them ideal calibrators for the gravitational low-frequency wave detector LISA mission. However, current theoretical evolution models still fail to explain the observed properties of the known populations of white dwarfs in both interacting and detached binaries. Major limitations are that the existing population models have generally been developed to explain the properties of sub-samples of these systems, occupying small volumes of the vast parameter space, and that the observed samples are severely biased. The overarching goal for the next decade is to assemble a large and homogeneous sample of white dwarf binaries that spans the entire range of evolutionary states, to obtain precise measurements of their physical properties, and to further develop the theory to satisfactorily reproduce the properties of the entire population. While ongoing and future all-sky high- and low-resolution optical spectroscopic surveys allow us to enlarge the sample of these systems, high-resolution ultraviolet spectroscopy is absolutely essential for the characterization of the white dwarfs in these binaries. The Hubble Space Telescope is currently the only facility that provides ultraviolet spectroscopy, and with its foreseeable demise, planning the next ultraviolet mission is of utmost urgency.
This paper outlines the importance of understanding jets from compact binaries for the problem of understanding the broader phenomenology of jet production. Because X-ray binaries are nearby and bright, have well-measured system parameters, and vary
by factors of $sim 10^6$ on $sim$ year timescales, they provide a unique opportunity to understand how various aspects of the jet physics change in response to changes in the accretion flow, giving the possibility of looking for trends within individual systems and testing their universality with other systems, rather than trying to interpret large samples of objects on a statistical basis.
Knowledge of protostellar evolution has been revolutionized with the advent of surveys at near-infrared to submillimeter wavelengths. This has enabled the bolometric luminosities and bolometric temperatures (traditional protostellar evolution diagnos
tics) to be measured for large numbers of protostars. However, further progress is difficult without knowing the masses of the central protostars. Protostar masses can be most accurately determined via molecular line kinematics from millimeter interferometers (i.e., ALMA). Theoretical investigations have predicted the protostellar mass function (PMF) for various protostellar mass accretion models, and it is now imperative to observationally constrain its functional form. While ALMA has enabled protostellar mass measurements, samples approaching 100 sources are necessary to constrain the functional form of the PMF, and upgrades to ALMA and/or a new mm/cm facility will increase the feasibility of measuring such a large number of protostar masses. The masses of protostars will enable their stellar structure (radius and intrinsic luminosity), evolution, and accretion histories to be better understood. This is made more robust when effective temperatures and accretion rates can be measured via ground/space-based near to mid-infrared spectroscopy. Furthermore, access to supercomputing facilities is essential to fit the protostar masses via radiative transfer modeling and updated theoretical/numerical modeling of stellar structure may also be required.
Direct determination of fundamental stellar parameters has many profound and wide-ranging impacts throughout astrophysics. These determinations are rooted in high angular resolution observations. In particular, as long-baseline optical interferometry
has matured over the past decade, increasingly large survey samples are serving to empirically ground the basic parameters of these building blocks of the universe. True imaging and improved parametric fitting are becoming routinely available, an essential component of fully characterizing stars, stellar environments, and planets these stars may host.
Galactic binaries with orbital periods less than $approx$1 hr are strong gravitational wave sources in the mHz regime, ideal for the Laser Interferometer Space Antenna (LISA). In fact, theory predicts that emph{LISA} will resolve tens of thousands of
Galactic binaries individually with a large fraction being bright enough for electromagnetic observations. This opens up a new window where we can study a statistical sample of compact Galactic binaries in both, the electromagnetic as well the gravitational wavebands. Using multi-messenger observations we can measure tidal effects in detached double WD systems, which strongly impact the outcome of WD mergers. For accreting WDs as well as NS binaries, multi-messenger observations give us the possibility to study the angular momentum transport due to mass transfer. In this white paper we present an overview of the opportunities for research on Galactic binaries using multi-messenger observations and summarize some recommendations for the 2020 time-frame.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
