Observations of the nebulosities near SN 1987A

Wampler, E. J.; Wang, Lifan; Baade, D.; Banse, Klaus; D’Odorico, S.; Gouiffès, C.; Tarenghi, M.

doi:10.1086/185836

Cited by 105 publications

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“…In addition to the Ha spots, the He I A10830 emission analyzed by Allen et al (1989) is concentrated to a region displaced by 0"8 from the supernova. On a larger scale, Wampler et al (1990) found that diffuse nebulosity extends out to roughly 6" from the supernova towards the north. This structure is mainly seen in red continuum images.…”

Section: Observationsmentioning

confidence: 98%

The narrow emission lines from SN 1987 A

Lundqvist¹

1992

PASP

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ABSTRACT. Observations of the narrow lines from SN 1987A have been reviewed, along with model interpretations of these observations. In addition, a discussion is provided on characteristics of the radiation from the supernova outburst, and how this affects the thermal structure of the circumstellar gas. Preliminary results from 2D hydrodynamical calculations for the circumstellar structure are also presented.

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Section: Observationsmentioning

confidence: 98%

The narrow emission lines from SN 1987 A

Lundqvist¹

1992

PASP

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“…The discovery led to further observations with ground-based telescopes (Crotts et al 1989;Wampler et al 1990) and the HST (Jakobsen et al 1991;Plait et al 1995). The observations have shown that the inner ring of SN 1987A (henceforth referred to as the equatorial ring, ER) has an enhanced nitrogen abundance, which is N/C = 5.0 ± 2.0, and N/O = 1.1 ± 0.4 times the solar (Lundqvist & Fransson 1996).…”

Section: Introductionmentioning

confidence: 99%

The outer rings of SN 1987A

Tziamtzis

Lundqvist

Gröningsson

et al. 2011

A&A

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Aims. We investigate the physical properties and structure of the outer rings of SN 1987A to understand their formation and evolution. Methods. We used low resolution spectroscopy from VLT/FORS1 and high resolution spectra from VLT/UVES to estimate the physical conditions in the outer rings, using nebular analysis for emission lines such as [ . We also measured the velocity at two positions of the outer rings to test a geometrical model for the rings. Additionally, we used data from the HST science archives to check the evolution of the outer rings of SN 1987A for a period that covers almost 11 years. Results. We measured the flux in four different regions, two for each outer ring. We chose regions away from the two bright neighbouring stars and as far as possible from the inner ring and created light curves for the emission lines of [O III], Hα, and [N II]. The light curves display a declining behaviour, which is consistent with the initial supernova-flash powering of the outer rings. The electron density of the emitting gas in the outer rings, as estimated by nebular analysis from the [O II] and [S II] lines, is < ∼ 3 × 10 3 cm −3 , has not changed over the last ∼15 years, and the [N II] temperature remains also fairly constant at ∼1.2 × 10 4 K. We find no obvious difference in density and temperature for the two outer rings. The highest density, as estimated from the decay of Hα, could be ∼5 × 10 3 cm −3 however, and because the decay is somewhat faster in the southern outer ring than it is in the northern, the highest density in the outer rings may be found in the southern outer ring. For an assumed distance of 50 kpc to the supernova, the distance between the supernova and the closest parts of the outer rings could be as short as ∼1.7 × 10 18 cm. Interaction between the supernova ejecta and the outer rings could therefore start in less than ∼20 years. We do not expect the outer rings to show the same optical display as the equatorial ring when this happens. Instead soft X-rays should provide a better way of observing the ejecta -outer rings interaction.

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“…All of these possibilities were equally promising until the ESO ground-based New Technology Telescope (Wampler et al 1990) and the NASA/ESA Hubble Space Telescope (Jakobsen et al 1991) discovered intricate ring structures around SN 1987A. The existence of these structures imposes severe constraints on the pattern of evolution of the presuperno-va, necessitating deviations from spherical symmetry, at least shortly before the supernova explosion.…”

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confidence: 99%

The light curve of supernova 1987A: The structure of the presupernova and radioactive nickel mixing

Utrobin

2004

Astron. Lett.

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Abstract-We have studied the influence of the presupernova structure and the degree of 56 Ni mixing on the bolometric light curve of SN 1987A in terms of radiation hydrodynamics in the one-group approximation by abandoning LTE and by taking into account nonthermal ionization and the contribution of spectral lines to its opacity. Our study shows that moderate 56 Ni mixing at velocities ≤2500 km scan explain the observed light curve if the density of the outer layers of the presupernova exceeds the value obtained in the evolutionary model of a single nonrotating star severalfold. Abandoning LTE and allowing for nonthermal ionization when solving the equation of state and calculating the mean opacities and the thermal emission coefficient leads to a significant difference between the gas temperature and the radiation temperature in the optically thin layers of the supernova envelope. We demonstrate the fundamental role of the contribution of spectral lines to the opacity in an expanding envelope and of the accurate description of radiative transfer in reproducing the observed shape of the bolometric light curve. We have found that disregarding the contribution of spectral lines to the opacity introduces an error of ∼20% into the explosion energy, and that a similar error is possible when determining the mass of the ejected matter. The resonant scattering of radiation in numerous lines accelerates the outer layers to velocities of ≈36 000 km s −1 ; this additional acceleration affects the outer layers with a mass of ≈10 −6 M . Proper calculations of the supernova luminosity require that not only the delay effects, but also the limb-darkening effects be taken into account.

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Observations of the nebulosities near SN 1987A

Cited by 105 publications

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The narrow emission lines from SN 1987 A

The narrow emission lines from SN 1987 A

The outer rings of SN 1987A

The light curve of supernova 1987A: The structure of the presupernova and radioactive nickel mixing

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