HST-COS OBSERVATIONS OF HYDROGEN, HELIUM, CARBON, AND NITROGEN EMISSION FROM THE SN 1987A REVERSE SHOCK

Abstract. Carbon (C) and nitrogen (N) released from biomass burning have multiple effects on the Earth's biogeochemical cycle, climate change, and ecosystem. These effects depend on the relative abundances of C and N species emitted, which vary with fuel type and combustion conditions. This study systematically investigates the emission characteristics of biomass burning under different fuel moisture contents, through controlled burning experiments with biomass and soil samples collected from a typical alpine forest in North America. Fuel moisture in general lowers combustion efficiency, shortens flaming phase, and introduces prolonged smoldering before ignition. It increases emission factors of incompletely oxidized C and N species, such as carbon monoxide (CO) and ammonia (NH3). Substantial particulate carbon and nitrogen (up to 4 times C in CO and 75% of N in NH3) were also generated from high-moisture fuels, maily associated with the pre-flame smoldering. This smoldering process emits particles that are larger and contain lower elemental carbon fractions than soot agglomerates commonly observed in flaming smoke. Hydrogen (H)/C ratio and optical properties of particulate matter from the high-moisture fuels show their resemblance to plant cellulous and brown carbon, respectively. These findings have implications for modeling biomass burning emissions and impacts.

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Recent Hubble Space Telescope Observations of SN 1987A: Broad Emission Lines

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313009150 ◽

2013 ◽

Vol 9 (S296) ◽

pp. 1-8

Author(s):

Kevin France

Keyword(s):

Shock Front ◽

Hubble Space Telescope ◽

Neutral Hydrogen ◽

Maximum Velocity ◽

Physical Structure ◽

Late Time ◽

Reverse Shock ◽

Chemical Abundances ◽

Space Telescope ◽

Sn 1987A

AbstractObservations with the Hubble Space Telescope (HST), conducted since 1990, have allowed us to create a “movie” of the evolution of the core-collapse supernova SN 1987A from 3–25 years after the explosion. Critical to understanding the late time evolution of SN 1987A was the successful HST Servicing Mission 4 in May 2009. The repair of the STIS instrument and the installation of the WFC3 imager and COS spectrograph have provided crucial data points for understanding the temporal variability in the physical structure and energy sources for SN 1987A, as well as measurements of the chemical abundances of the ejecta. In this proceeding, I will focus on two topics that have made use of the expanded capability of HST and highlight the importance of access to a UV/optical space observatory for the studies of local supernovae: 1) 2) The decreasing maximum velocity of neutral hydrogen crossing the reverse shock front and the role of soft X-ray/EUV heating in the outer supernova debris and 2) The detection of metals (N4+ and C3+ ions) crossing the reverse shock front and CNO processing in the progenitor star.

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LATE SPECTRAL EVOLUTION OF THE EJECTA AND REVERSE SHOCK IN SN 1987A

The Astrophysical Journal ◽

10.1088/0004-637x/768/1/88 ◽

2013 ◽

Vol 768 (1) ◽

pp. 88 ◽

Cited By ~ 28

Author(s):

Claes Fransson ◽

Josefin Larsson ◽

Jason Spyromilio ◽

Roger Chevalier ◽

Per Gröningsson ◽

...

Keyword(s):

Spectral Evolution ◽

Reverse Shock ◽

Sn 1987A

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Three-dimensional mixing and light curves: constraints on the progenitor of supernova 1987A

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834976 ◽

2019 ◽

Vol 624 ◽

pp. A116 ◽

Cited By ~ 12

Author(s):

V. P. Utrobin ◽

A. Wongwathanarat ◽

H.-Th. Janka ◽

E. Müller ◽

T. Ertl ◽

...

Keyword(s):

Light Curve ◽

Maximum Velocity ◽

Light Curves ◽

3D Analysis ◽

Reverse Shock ◽

Core Mass ◽

Single Star ◽

Sn 1987A ◽

Supernova 1987A ◽

Larger Sample

With the same method as used previously, we investigate neutrino-driven explosions of a larger sample of blue supergiant models. The blue supergiants were evolved as single-star progenitors. The larger sample includes three new presupernova stars. The results are compared with light-curve observations of the peculiar type IIP supernova 1987A (SN 1987A). The explosions were modeled in 3D with the neutrino-hydrodynamics code PROMETHEUS-HOTB, and light-curve calculations were performed in spherical symmetry with the radiation-hydrodynamics code CRAB, starting at a stage of nearly homologous expansion. Our results confirm the basic findings of the previous work: 3D neutrino-driven explosions with SN 1987A-like energies synthesize an amount of 56Ni that is consistent with the radioactive tail of the light curve. Moreover, the models mix hydrogen inward to minimum velocities below 400 km s−1 as required by spectral observations and a 3D analysis of molecular hydrogen in SN 1987A. Hydrodynamic simulations with the new progenitor models, which possess smaller radii than the older ones, show much better agreement between calculated and observed light curves in the initial luminosity peak and during the first 20 days. A set of explosions with similar energies demonstrated that a high growth factor of Rayleigh–Taylor instabilities at the (C+O)/He composition interface combined with a weak interaction of fast Rayleigh–Taylor plumes, where the reverse shock occurs below the He/H interface, provides a sufficient condition for efficient outward mixing of 56Ni into the hydrogen envelope. This condition is realized to the required extent only in one of the older stellar models, which yielded a maximum velocity of around 3000 km s−1 for the bulk of ejected 56Ni, but failed to reproduce the helium-core mass of 6 M⊙ inferred from the absolute luminosity of the presupernova star. We conclude that none of the single-star progenitor models proposed for SN 1987A to date satisfies all constraints set by observations.

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3D MHD modeling of the expanding remnant of SN 1987A

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834487 ◽

2019 ◽

Vol 622 ◽

pp. A73 ◽

Cited By ~ 10

Author(s):

S. Orlando ◽

M. Miceli ◽

O. Petruk ◽

M. Ono ◽

S. Nagataki ◽

...

Keyword(s):

Magnetic Field ◽

Radio Emission ◽

Blast Wave ◽

Stellar Surface ◽

Reverse Shock ◽

X Ray ◽

Origin And Evolution ◽

Ambient Magnetic Field ◽

Sn 1987A ◽

The Impact

Aims. We investigate the role played by a pre-supernova (SN) ambient magnetic field in the dynamics of the expanding remnant of SN 1987A, and the origin and evolution of the radio emission from the remnant, in particular during the interaction of the blast wave with the nebula surrounding the SN. Methods. We modeled the evolution of SN 1987A from the breakout of the shock wave at the stellar surface to the expansion of its remnant through the surrounding nebula using three-dimensional magnetohydrodynamic simulations. The model considers the radiative cooling, the deviations from equilibrium of ionization, the deviation from temperature-equilibration between electrons and ions, and a plausible configuration of the pre-SN ambient magnetic field. We explore the strengths of the pre-SN magnetic field ranging between 1 and 100 μG at the inner edge of the nebula and we assume an average field strength at the stellar surface B0 ≈ 3 kG. From the simulations, we synthesize the thermal X-ray and the non-thermal radio emission and compare the model results with observations. Results. The presence of an ambient magnetic field with strength in the range considered does not change significantly the overall evolution of the remnant. Nevertheless, the magnetic field reduces the erosion and fragmentation of the dense equatorial ring after the impact of the SN blast wave. As a result, the ring survives the passage of the blast, at least during the time covered by the simulations (40 yr). Our model is able to reproduce the morphology and lightcurves of SN 1987A in both X-ray and radio bands. The model reproduces the observed radio emission if the flux originating from the reverse shock is heavily suppressed. In this case, the radio emission originates mostly from the forward shock traveling through the H II region and this may explain why the radio emission seems to be insensitive to the interaction of the blast with the ring. Possible mechanisms for the suppression of emission from the reverse shock are investigated. We find that synchrotron self-absorption and free–free absorption have negligible effects on the emission during the interaction with the nebula. We suggest that the emission from the reverse shock at radio frequencies might be limited by highly magnetized ejecta.

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Heating and Nonequilibrium Distributions of Ions in a Reverse Shock Wave of the SN 1987A Remnant

Physics of Atomic Nuclei ◽

10.1134/s1063778818010155 ◽

2018 ◽

Vol 81 (1) ◽

pp. 139-145

Author(s):

Yu. A. Kropotina ◽

A. M. Bykov ◽

A. V. Kozlova ◽

A. M. Krassilchtchikov ◽

K. P. Levenfish ◽

...

Keyword(s):

Shock Wave ◽

Reverse Shock ◽

Sn 1987A

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Metabolic signalling and the partitioning of resources in plant storage organs

The Journal of Agricultural Science ◽

10.1017/s0021859699006978 ◽

1999 ◽

Vol 133 (3) ◽

pp. 243-249 ◽

Cited By ~ 3

Author(s):

NIGEL G. HALFORD

Keyword(s):

Dry Weight ◽

Wild Relatives ◽

Crop Plants ◽

Wild Plants ◽

Young Plant ◽

Carbon And Nitrogen ◽

Cultivated Potato ◽

Metabolic Signalling ◽

Storage Organs ◽

Plant Storage

The most important harvested organs of crop plants, such as seeds, tubers and fruits, are often described as assimilate sinks. They play little or no part in the fixation of carbon through the production of sugars through photosynthesis, or in the uptake of nitrogen and sulphur, but import these assimilated resources to support metabolism and to store them in the form of starch, oils and proteins. Wild plants store resources in seeds and tubers to later support an emergent young plant. Cultivated crops are effectively storing resources to provide us with food and many have been bred to accumulate much more than would be required otherwise. For example, approximately 80% of a cultivated potato plant's dry weight is contained in its tubers, ten times the proportion in the tubers of its wild relatives (Inoue & Tanaka 1978). Cultivation and breeding has brought about a shift in the partitioning of carbon and nitrogen assimilate between the organs of the plant.

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Distance to SN 1987A and the LMC

Symposium - International Astronomical Union ◽

10.1017/s0074180900118959 ◽

1999 ◽

Vol 190 ◽

pp. 549-554

Author(s):

Nino Panagia

Keyword(s):

Angular Size ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Light Curves ◽

Distance Modulus ◽

Absolute Size ◽

Sn 1987A

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.

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