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 Observations of Interstellar HI Toward Nearby Late-Type Stars

1984 ◽  
Vol 81 ◽  
pp. 60-63
Author(s):  
Wayne B. Landsman ◽  
Richard C. Henry ◽  
H. Warren Moos ◽  
Jeffrey L. Linsky
Keyword(s):  
Interstellar Medium ◽  
High Dispersion ◽  
The Sun ◽  
Local Interstellar Medium ◽  
Late Type ◽  
Upper Limits

AbstractHigh-dispersion Copernicus and IUE observations of chromospheric Ly α emission are used to study the distribution of HI in the local interstellar medium. Interstellar parameters are derived toward 3 stars within 5 pc of the sun, and upper limits are given for the Ly a flux from 9 other stars within 10 pc.

scholarly journals White Dwarf Probes of Interstellar Deuterium

2000 ◽  
Vol 198 ◽  
pp. 485-486
Author(s):  
Wayne Landsman
Keyword(s):  
High Resolution ◽  
Interstellar Medium ◽  
White Dwarf ◽  
White Dwarfs ◽  
Accurate Determination ◽  
The Sun ◽  
Local Interstellar Medium ◽  
Space Telescope ◽  
Imaging Spectrograph

We review the advantages of using hot white dwarfs (WDs) as probes of the deuterium abundance in the local interstellar medium. We then discuss advantages of the Space Telescope Imaging Spectrograph (STIS) for such observations, as compared with earlier observations with the Goddard High Resolution Spectrograph (GHRS). The GHRS Ly α profile of the white dwarf HZ 43 is probably modified by the hot ‘hydrogen wall’ surrounding the Sun; but despite this complication, the sightline remains a promising one for an accurate determination of the deuterium abundance in the local interstellar medium.

Further high-resolution NA I observations of the local interstellar medium

1991 ◽  
Vol 381 ◽  
pp. 462 ◽  
Author(s):  
B. Y. Welsh ◽  
P. W. Vedder ◽  
J. V. Vallerga ◽  
N. Craig
Keyword(s):  
High Resolution ◽  
Interstellar Medium ◽  
Local Interstellar Medium

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.

High-resolution CA II observations of the local interstellar medium

1993 ◽  
Vol 411 ◽  
pp. 729 ◽  
Author(s):  
J. V. Vallerga ◽  
P. W. Vedder ◽  
N. Craig ◽  
B. Y. Welsh
Keyword(s):  
High Resolution ◽  
Interstellar Medium ◽  
Local Interstellar Medium

Goddard high-resolution spectrograph observations of the local interstellar medium and the deuterium/hydrogen ratio along the line of sight toward Capella

1993 ◽  
Vol 402 ◽  
pp. 694 ◽  
Author(s):  
Jeffrey L. Linsky ◽  
Alexander Brown ◽  
Ken Gayley ◽  
Athanassios Diplas ◽  
Blair D. Savage ◽  
...  
Keyword(s):  
High Resolution ◽  
Interstellar Medium ◽  
Line Of Sight ◽  
Local Interstellar Medium

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.

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