Decades-Long Changes of the Interstellar Wind Through Our Solar System

Science ◽  
2013 ◽  
Vol 341 (6150) ◽  
pp. 1080-1082 ◽  
Author(s):  
P. C. Frisch ◽  
M. Bzowski ◽  
G. Livadiotis ◽  
D. J. McComas ◽  
E. Moebius ◽  
...  
Keyword(s):  
Solar System ◽  
Interstellar Medium ◽  
The Sun ◽  
Local Interstellar Medium ◽  
Data Types ◽  
Explorer Mission ◽  
Interstellar Material ◽  
Ecliptic Longitude

The journey of the Sun through the dynamically active local interstellar medium creates an evolving heliosphere environment. This motion drives a wind of interstellar material through the heliosphere that has been measured with Earth-orbiting and interplanetary spacecraft for 40 years. Recent results obtained by NASA's Interstellar Boundary Explorer mission during 2009–2010 suggest that neutral interstellar atoms flow into the solar system from a different direction than found previously. These prior measurements represent data collected from Ulysses and other spacecraft during 1992–2002 and a variety of older measurements acquired during 1972–1978. Consideration of all data types and their published results and uncertainties, over the three epochs of observations, indicates that the trend for the interstellar flow ecliptic longitude to increase linearly with time is statistically significant.

scholarly journals The Intrinsic Properties of the Local Interstellar Medium

1997 ◽  
Vol 166 ◽  
pp. 29-32 ◽  
Author(s):  
Olivia Puyoo ◽  
Lotfi Ben Jaffel
Keyword(s):  
Solar System ◽  
Interstellar Medium ◽  
Interstellar Cloud ◽  
Actual State ◽  
The Sun ◽  
Local Interstellar Medium ◽  
Intrinsic Properties ◽  
Hydrogen Density ◽  
Self Consistent ◽  
Local Cloud

AbstractWe propose a new method to constrain the actual state of the interstellar cloud that surrounds the solar system. Using Voyager UVS Lyman-α sky maps and the powerful principle of invariance, we derive the H distribution all along the spacecraft path. Provided current models of the heliopause interface between the solar and the interstellar winds, we extrapolate this distribution to farther distances from the Sun and infer in a self consistent way key parameters of the local cloud. Our findings are a high interstellar hydrogen density of ~ 0.24 cm−3 and a weak ionization .

scholarly journals Observations of Local Interstellar Mg I and Mg II

1984 ◽  
Vol 81 ◽  
pp. 64-66 ◽  
Author(s):  
F. Bruhweiler ◽  
W. Oegerle ◽  
E. Weiler ◽  
R. Stencel ◽  
Y. Kondo
Keyword(s):  
High Resolution ◽  
Interstellar Medium ◽  
The Sun ◽  
Local Interstellar Medium ◽  
Upper Limits

AbstractWe have combined Copernicus and IUE observations of 5 stars within 50 pc of the Sun to study the ionization of magnesium in the local interstellar medium (LISM). The high resolution Copernicus spectrometer was used to detect interstellar Mg I 2852 in the spectra of α Gru, α Eri, and α Lyr, while placing upper limits on Mg I in the spectra of α CMa and α PsA. Observations of Mg II 2795, 2802 for these stars were also obtained with IUE and Copernicus. The column densities of Mg I and Mg II are used to place constraints on the temperature of the LISM.

scholarly journals Heating of the Interstellar Medium by Supernova Remnants

1983 ◽  
Vol 101 ◽  
pp. 385-392
Author(s):  
Donald P. Cox
Keyword(s):  
Interstellar Medium ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Low Density ◽  
The Sun ◽  
X Ray ◽  
Interstellar Material ◽  
X Ray Background

We observe the heating of interstellar material in young supernova remnants (SNR). In addition, when analyzing the soft X-ray background we find evidence for large isolated regions of apparently hot, low density material. These, we infer, may have been heated by supernovae. One such region seems to surround the Sun. This has been modeled as a supernova remnant viewed from within. The most reasonable parameters are ambient density no ~ 0.004 cm−3, radius of about 100 pc, age just over 105 years (Cox and Anderson 1982).

scholarly journals Kinematical Structure of the Local Interstellar Medium

1997 ◽  
Vol 166 ◽  
pp. 195-198
Author(s):  
R. Génova ◽  
J. E. Beckman ◽  
J. Rodríguez Álamo
Keyword(s):  
Interstellar Medium ◽  
Velocity Vector ◽  
Galactic Center ◽  
Galactic Plane ◽  
The Sun ◽  
Local Interstellar Medium

AbstractObservations of interstellar Na I in the spectra of 93 stars within 315 pc from the Sun show that it lies in a tunnel of gas moving away from Scorpio-Centaurus and is surrounded by gas moving toward the Galactic center.Gas approaches the Sun from Scorpio-Centaurus expanding from (r, l, b)=(160 pc, 313°7, +28°2) with LSR velocity 15.3 km s−1. The radius of this shell is 153 pc.We identify these clouds:D: velocity vector (υd, ld, bd)=(+7.2 km s−1, 305°1, −13°5), above and below the Galactic plane (GP) in the range of Galactic longitudes 357°–55°.C: velocity vector (υc, lc, bc)=(+11.5 km s−1, 349°0, −35°2), above and below the GP in the range 30°≤l≤110°.M: velocity vector (υm, lm, bm)=(+21.9 km s−1, 34°2, +1°5), above and below the GP in the range 100°≤l≤130°.P: velocity vector (υp, lp, bp)=(+13.8 km s−1, 244°9, +5°4), above and below the GP from l~120° to the limit of our data at l~210°.E: velocity vector (υe, le, be)=(+16.8 km s−1, 208°4, +6°2) in the range 160°≤l≤185° and −10°≤b≤–35°.A: velocity vector (υa, la, ba)=(+12.9 km s−1, 73°6, −5°6) towards the Galactic anti-center, below the GP.I: velocity vector (υi, li, bi)=(+37.7 km s−1, 132°8, −64°3) towards the Galactic anti-center, above the GP.

scholarly journals The Morphology and Physics of the Local Interstellar Medium

1996 ◽  
Vol 152 ◽  
pp. 261-268 ◽  
Author(s):  
Fredrick C. Bruhweiler
Keyword(s):  
Interstellar Medium ◽  
Radiation Field ◽  
Special Role ◽  
Low Density ◽  
The Sun ◽  
Local Interstellar Medium ◽  
Density Region ◽  
Direct Measurements ◽  
Extreme Uv ◽  
Local Cloud

We are finally on the threshold of obtaining a coherent morphological and physical picture for the local interstellar medium (LISM), especially the region within 300 pc of the Sun. The EUVE is playing a special role in revealing this picture. This instrument can provide direct measurements of the the radiation field that photoionizes both hydrogen and helium. It also can yield direct measurements of the column densities of hydrogen, but especially He I and He II toward nearby white dwarfs. These observations suggest that the ionization in the Local Cloud, the cloud in which the Sun is embedded, is not in equilibrium, but in a recombination phase. Heuristic calculations imply that the the present ionization is due to the passage of shocks, at times greater than 3 × 106 years ago. The origin of these shocks are probably linked to the supernova which was responsible for the expanding nebular complex of clouds know as the Loop I supernova remnant, of which the Local Cloud is a part, extreme- UV radiation field, that which ionizes both hydrogen and helium in the LISM. Of the ISM within 300 pc, the volume appears to be predominantly filled by hot (106 K) coronal gas. This gas is laced with six largescale shell structures with diameters ~100−150 pc including the long-recognized radio loops, Loop I−IV, as well as the Orion-Eridanus and Gum Nebulae are identified. An idea that has evolved in the literature for over two decades is that the kinematically-linked OB associations representing Gould’s Belt, plus the gas and dust of Lindblad’s Ring, require that previous supernova activity and stellar winds carved out a 400–600 pc diameter cavity some 3 to 6 × 107 yr ago. This activity produced a pre-existing low density region, into which the present young loop structures have expanded. The outer boundaries of the identified expanding loop structures, inside this preexisting cavity, delineate the periphery of the the mis-named “local interstellar bubble.” Thus, this picture naturally explains some of the problems often associated with the presence of this low density region exterior to Loop I.

Neutral component of the local interstellar medium

2019 ◽  
Vol 91 (2) ◽  
pp. 272-280 ◽  
Author(s):  
Wojciech Konior ◽  
Romana Ratkiewicz ◽  
Jan Kotlarz
Keyword(s):  
Interstellar Medium ◽  
Impact Ionization ◽  
Current Knowledge ◽  
Experimental Investigations ◽  
Interstellar Space ◽  
The Sun ◽  
Neutral Component ◽  
Local Interstellar Medium ◽  
Hydrogen Atoms ◽  
Content Type

Purpose This paper aims to review the current knowledge about the neutral component of the local interstellar medium (LISM), which due to the resonant charge exchange, photoionization and electron impact ionization processes has a profound impact on the heliosphere structure. Design/methodology/approach This work is based on the heliospheric literature review. Findings The summary of four major effects of neutral hydrogen atoms penetrating solar wind (SW), i.e. the disappearance of the complicated flow structure; the emergence of “hydrogen wall” in front of the heliopause (HP); decreasing distance of termination shock (TS), HP and bow shock (BS) layer from the Sun; and recently discovered by the Interstellar Boundary Explorer mission, a region of enhanced energetic neutral atom (ENA) emission seen in all sky maps as a ribbon. Practical implications In the context of constantly developing space technologies in aerospace engineering and prospective deep space missions, there is a need of general reviews about the interstellar space surroundings of the Sun and gathering the knowledge to help in theoretical, numerical and experimental investigations such as the optimization of the scientific equipment and spacecraft structure to work in specific conditions. Originality/value The survey encapsulate basic and relevant processes playing an important role in the physics of the nearest surroundings of the Sun and the latest results of numerical and experimental investigations focused on the neutral LISM component and its influence on the heliosphere, which is strongly desired in future works. Until now, not many of such reviews have been done.

scholarly journals Interstellar Scintillation Studies of Pulsars and Distribution of Scattering Plasma in the Local Interstellar Medium

2001 ◽  
Vol 182 ◽  
pp. 171-174
Author(s):  
N.D. Ramesh Bhat ◽  
Yashwant Gupta ◽  
A. Pramesh Rao ◽  
P.B. Preethi
Keyword(s):  
Interstellar Medium ◽  
Radio Telescope ◽  
Plasma Turbulence ◽  
Solar Neighborhood ◽  
Component Model ◽  
The Sun ◽  
Local Interstellar Medium ◽  
Local Bubble ◽  
Interstellar Scintillation

AbstractPulsar scintillation measurements from the Ooty Radio Telescope (ORT) are used to investigate the distribution of scattering in the Local Interstellar Medium (LISM; region of ≲ 1 kpc of the Sun), specifically the region in and around the Local Bubble. A 3-component model, where the Solar neighborhood is surrounded by a shell of enhanced plasma turbulence, is proposed for the LISM. Further, the Ooty data, along with those from Parkes and other telescopes are used for investigating the distribution of scattering towards the nearby Loop I Superbubble.

Interstellar Probe: A Mission to Explore the Heliospheric Boundary and Interstellar Medium

2021 ◽  
Author(s):  
Pontus Brandt ◽  
Ralph McNutt ◽  
Elena Provornikova ◽  
James Kinnison ◽  
Carey Lisse ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Interstellar Medium ◽  
Interstellar Dust ◽  
Space Exploration ◽  
Accurate Determination ◽  
Galactic Cosmic Rays ◽  
The Sun ◽  
Current State ◽  
Interstellar Material ◽  
Interstellar Probe

<p>During its evolution, the Sun and its protective magnetic bubble – the heliosphere - has completed nearly twenty revolutions around the Galactic Core. During this “Solar Journey” it has plowed through widely different interstellar environments that have all shaped the system we live in today. The orders-of-magnitude differences in interstellar properties have had dramatic consequences for the penetration of interstellar material and have affected elemental and isotopic abundances, atmospheric evolution and perhaps even conditions for habitability. As far as we know, only some 60, 000 years ago, the Sun entered what we call the Local Interstellar Cloud (LIC), and in less than 1,900 years the Sun will be entering a very different interstellar environment that will continue to shape its evolution and fate.</p><p>The Interstellar Probe is a pragmatic mission with a possible launch already in the next decade that would explore the heliospheric boundary and how it interacts with the Very Local Interstellar Medium (VLISM) to understand the current state along this Solar Journey and, ultimately understand where our home came from, and where we are going. During its 50-year nominal design life, it would go far beyond where the Voyager missions have gone, out to about 400 astronomical units (au) and likely survive out to 1000 au. Therefore, the Interstellar Probe mission would represent humanity’s first explicit step in to the galaxy and become NASA's boldest step in space exploration.</p><p>When the Voyager missions traversed the heliospheric boundary with their very limited payload it became clear that we are faced with a whole new regime of space physics that is not only decisive for our own heliosphere, but also for understanding the physics of other astrospheres as well. Today we still do not understand the force that is upholding the magnetic shell (the heliosheath) around our heliosphere, or the mechanisms that shield the solar system from galactic cosmic rays, and many other mysteries. Once beyond where the furthest Voyager spacecraft will cease operations (likely at ~170 au), Interstellar Probe would step in to the unknown, traverse the hydrogen wall and the complex magnetic topology at the very edge of the Sun’s sphere of influence, and then directly sample for the first time the interstellar material that has made all of us. There, measurements of the unperturbed gas, plasma, and fields would allow accurate determination of the current state of the LIC and how it affects the global heliosphere. Measurements of unshielded interstellar dust and galactic cosmic rays would provide unprecedented information on stellar and galactic evolution. The physical processes that occur as the solar wind and magnetic field interact with VLISM would also provide the only directly measurable prototypes for understanding the astrospheres surrounding other stars that control the atmospheres and habitability of their exoplanets. All this newly acquired knowledge would then enable an understanding of the current state of the heliosphere and the VLISM, and how they interact, which ultimately can be used to extrapolate the understanding of our system back to the past and into the future.</p><p>At the same time, the outward trajectory is a natural opportunity for exploring one of the ~4,000 Kuiper Belt Objects or ~130 dwarf planets similar to and beyond Pluto and determine the large-scale structure of the circum-solar dust disk to provide the ground truth for planetary system formation in general. Once beyond the obscuring dust, the infrared sky would open a window to early galaxy formation.</p><p>An Interstellar Probe has been discussed and studied since 1960, but the stumbling block has always been propulsion. Now this hurdle has been overcome by the availability of new and larger launch vehicles. An international team of scientists and experts are now in the final year of a NASA-funded study led by The Johns Hopkins University Applied Physics Laboratory (APL) to develop pragmatic example mission concepts for Interstellar Probe with a nominal design lifetime of 50 years. Together with the Space Launch System (SLS) Program Office at NASA’s Marshall Space Flight Center, the team has analyzed dozens of launch configurations and demonstrated that asymptotic speeds in excess of 7.5 au per year can be achieved using existing or near-term propulsion stages with a powered or passive Jupiter Gravity Assist (JGA). These speeds are more than twice that of the fastest escaping man-made spacecraft to date, which is Voyager 1 currently at 3.59 au/year. Launching near the nose direction of the heliosphere, Interstellar Probe would therefore reach the Termination Shock (TS) in less than 12 years and cross the Heliopause into the VLISM after about 16 years from launch.</p><p>In this presentation we provide an overview and update of the study, the science mission concept, the compelling discoveries that await, and the associated example science payload, measurements and operations ensuring a historic data return that would push the boundaries of space exploration by going where no one has gone before.</p><p> </p>

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