The interstellar medium near the sun. II - The line of sight to Alpha Virginis

1979 ◽  
Vol 228 ◽  
pp. 127 ◽  
Author(s):  
D. G. York ◽  
B. F. Kinahan
Keyword(s):  
Interstellar Medium ◽  
Line Of Sight ◽  
The Sun

scholarly journals Deuterium Abundance in the Local Interstellar Medium

1984 ◽  
Vol 81 ◽  
pp. 84-88
Author(s):  
R. Ferlet ◽  
C. Gry ◽  
A. Vidal-Madjar
Keyword(s):  
Interstellar Medium ◽  
Present Situation ◽  
Line Of Sight ◽  
Interstellar Space ◽  
The Sun ◽  
Local Interstellar Medium ◽  
The One

AbstractWe underline the present situation of deuterium abundance evaluation in interstellar space and show that it should be < 10-5. Studiing in more detail the λ Sco line of sight and having observed two Nal interstellar components toward that star, we can show that the D/H evaluation made toward λ Sco is in fact related to the local interstellar medium (less than 10 pc from the sun). Because this evaluation is also < 10-5 it is in stricking contrast with the one made toward α Aur (D/H > 1.8 10-5 ) confirming the fact that the deuterium abundance in the local interstellar medium varies by at least a factor of two over few parsecs.

scholarly journals Probe of the Nearby Interstellar Medium by the Vacant Line of Sight to β CMa

1984 ◽  
Vol 81 ◽  
pp. 80-83 ◽  
Author(s):  
C. Gry ◽  
D.G. York ◽  
A. Vidal-Madjar
Keyword(s):  
Interstellar Medium ◽  
Line Of Sight ◽  
The Sun ◽  
Ionization State ◽  
Ionization Equilibrium ◽  
Hii Region

AbstractThe line of sight to βCMa has been probed by Copernicus observations. This particular line of sight is remarkable for the low mean densities. We find n̄H ∼ .002 cm-3. However we can distinguish two separate regions:1) A local nearby HI region extends over a few parsecs from the sun with a density of the order of 0.1 cm-3 and a temperature of 11000 to 12500 K.2) An HII region lies somewhere beyond the HI region and is spread over about 60pc. Its total hydrogen mean density is of the same order as the HI region, i.e. of ∼0.1 cm-3 and it contains only elements in low ionization state. All the data are coherent with the picture of a cloud in ionization equilibrium at T ∼ 23 000° K.

scholarly journals Unbound Close Stellar Encounters in the Solar Neighborhood

2022 ◽  
Vol 163 (2) ◽  
pp. 44
Author(s):  
Bradley M. S. Hansen
Keyword(s):  
Spectral Type ◽  
Main Sequence ◽  
Radial Distance ◽  
Solar Neighborhood ◽  
Limiting Factors ◽  
Line Of Sight ◽  
The Sun ◽  
Finite Set ◽  
Host Stars ◽  
Migration Event

Abstract We present a catalog of unbound stellar pairs, within 100 pc of the Sun, that are undergoing close, hyperbolic, encounters. The data are drawn from the GAIA EDR3 catalog, and the limiting factors are errors in the radial distance and unknown velocities along the line of sight. Such stellar pairs have been suggested to be possible events associated with the migration of technological civilizations between stars. As such, this sample may represent a finite set of targets for a SETI search based on this hypothesis. Our catalog contains a total of 132 close passage events, featuring stars from across the entire main sequence, with 16 pairs featuring at least one main-sequence star of spectral type between K1 and F3. Many of these stars are also in binaries, so that we isolate eight single stars as the most likely candidates to search for an ongoing migration event—HD 87978, HD 92577, HD 50669, HD 44006, HD 80790, LSPM J2126+5338, LSPM J0646+1829 and HD 192486. Among host stars of known planets, the stars GJ 433 and HR 858 are the best candidates.

Variations in the Mean Line of Sight Velocity of the Sun: 1976 – 1985

1988 ◽  
pp. 215-218 ◽  
Author(s):  
A. Jiménez ◽  
P. L. Pallé ◽  
C. Régulo ◽  
T. Roca Cortés ◽  
Y. P. Elsworth ◽  
...  
Keyword(s):  
Line Of Sight ◽  
The Sun ◽  
The Mean

The Total Experience

Eclipses ◽  
2019 ◽  
Author(s):  
Frank Close
Keyword(s):  
Outer Space ◽  
Line Of Sight ◽  
The Sun

Why do colors change? In outer space, the sky is black and the Sun is a white disc, visible only in the direct line of sight—there is nothing to scatter its light. Here on Earth, in normal daylight the molecules and dust in the atmosphere...

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.

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