NA i Interstellar Absorption in the Direction of Two LMC Supergiants in the Field of SN 1987A
Abstract
Observations of Na I interstellar lines of the two LMC supergiants SK -69^deg^203 and Sk - 69^deg^211, at few arcminutes from the SN 1987A, have been obtained with the ESO CES spectrograph linked by fibers to the 3.6 m telescope at La Silla, Chile. Remarkable differences are found among the three contiguous lines of sight. The Galactic components have different strengths implying strong dishomogeneities of the interstellar gas of the Galactic disk on a scale of tenths of parsecs. The component of V_HEL_ ~ 64 km s^-1^ is much stronger toward Sk -69^deg^211 than toward SN 1987A and is almost absent in Sk -69^deg^203. The SN 1987A features at V_HEL_ ~ 216 km s^-1^, 253 km s^-1^ , and 269 km s^-1^ are absent from the spectra of the two supergiants and appear as a characteristic signature of the supernova line of sight. Finally, the main LMC absorption shows variations in strength and radial velocity between each pair of the three lines of sight, suggesting a complex distribution of the main body of the LMC IS gas in the direction of a supernova.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1989
- DOI:
- 10.1086/185420
- Bibcode:
- 1989ApJ...339L..63M
- Keywords:
-
- Absorption Spectra;
- Interstellar Matter;
- Magellanic Clouds;
- Sodium;
- Supergiant Stars;
- Supernova 1987a;
- Disk Galaxies;
- Line Of Sight;
- Line Spectra;
- Ultraviolet Astronomy;
- Astrophysics;
- GALAXIES: MAGELLANIC CLOUDS;
- INTERSTELLAR: MATTER;
- STARS: SUPERNOVAE