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1.
We present the spectrum of the supernova SN1988e over the wavelength range 4750–9000 Å as recorded on 11 February, 1988. The spectrum was taken in one 2000 s exposure using the Faint Object Spectrograph on the 4.2 m William Herschel Telescope (WHT) at the Observatorio del Roque de los Muchachos.We conclude that SN1988e was a type I supernova, and that at the time of observation it had faded 7.5 mag from its predicted magnitude at maximum light. Spectra taken at such late stages in the light curve are comparatively rare, and are made possible only with the application of modern instrumentation.  相似文献   

2.
We present two spectra of the supernova SN1988A in M58 (NGC4579) over the wavelength range 4000–9700 Å, as recorded by the Faint Object Spectrograph on the 4.2 m William Herschel Telescope at the Observatorio del Roque de los Muchachos. We conclude that SN1988A was a type II supernova.  相似文献   

3.
We carried out a Monte Carlo simulation calculation on the observed data of neutrino events of the supernova SN1987A. Our results show that the best value for the rest-mass of neutrino is 3–4 eV. We also calculated the light curve of the neutrino bursts and the energy spectrum.Our results impose constraints on the rest-mass of neutrino and the mass of the precursor of SN 1987A.  相似文献   

4.
Detailed observations of the [Oiii]5007 Å emission from the elliptical rings around SN 1987A suggest a model wherein the two faint, outer rings are due to emission from two circular toroids moving outwards (at 25 km s–1) along a bipolar cone centred on the site of the supernova. The brighter, central ring is expanding radially outward at 8.3 km s–1. The rings must have been created 2-3 × 104 years before the supernova explosion and are thought to be a consequence of the interaction of stellar winds emanating from the progenitor system during the final stages of its evolution to a supernova.  相似文献   

5.
An examination of the histogram of the supernova remnants radii allows one to deduce: (1) some support for the existence of a fairly dense galactic halo at least up to a few kpc from the galactic plane; (2) a first approximation for the initial energy distribution. Although the precise shape is still in doubt and various possibilities exist, one can conclude that the supernova rate should be no less than 1/150 SN yr–1, and no more than 1/70 SN yr–1; the average initial energy should be larger than 1.4×1049 erg.  相似文献   

6.
We consider an improved rotational mechanism of the explosion of a collapsing supernova. We show that this mechanism leads to two-stage collapse with a phase difference of ～5 h. Based on this model, we attempt a new interpretation of the events in underground neutrino detectors on February 23, 1987, related to the supernova SN 1987A.  相似文献   

7.
Chugai  N. N. 《Astronomy Letters》2020,46(5):319-323
Astronomy Letters - I explore the origin of an asymmetry of the H $$\alpha$$  emission from a circumstellar (CS) shell around type IIP supernova SN 2013fs in the spectrum taken 10.3 h...  相似文献   

8.
Implications from the available information on the supernova SN 1987 A are discussed for the supernova models. We derive an upper bound of 10–25 eV for the neutrino rest mass.  相似文献   

9.
V andB light curves for supernova 1987A covering some 120 days from the outburst are here presented and discussed; they are shown to be rather atypical for a type II supernova. The absolute magnitude at maximum brightness is also analyzed, and after applying a correction for interstellar absorption we obtainM V, max, 0 =–16.1, andM B, max, 0 =–14.7; is is then concluded that 1987A is a supernova quite fainter than average. A comparison with other known supernova is made and some similarity is found with peculiar objects such as 1948B in NGC 6946, and probably, 1909 A in M 101.Research supported in part by SECyT and CONICOR.  相似文献   

10.
We present the X-ray light curve in the 0.2–2.4 keV band based on fiveROSAT observations of SN1978K in NGC 1313. The X-ray emission is believed to arise from the interaction of the reverse shock and the expanding debris from the supernova. The reverse shock becomes established after the outgoing shock runs into circumstellar matter.  相似文献   

11.
Photographic image-tube spectra (150 Å mm–1, 4500 Å-7000 Å) of the type I supernova (1974g) in the Sc galaxy NGC 4414 obtained at phases+ 14 days and + 40 days past maximum light have been reduced to absolute flux. The positions of various spectral features and the overall appearance of the spectra of SN 1974g closely match previously observed type I SN spectra at similar phases. An electronographic isophotal map of NGC 4414 is presented, and an accurate position of SN 1974g given. A distance to NGC 4414 of 15 Mpc was determined from the recessional velocities and the diameters of Hii regions; while the absolute magnitude at maximum light of SN 1974g was found to beM B(max)=–19.0. Estimates of the radius of the expanding photosphere of SN 1974g, cetermined by two independent methods, giveR1015 cm in the early post-maximum phases. The time of outburst,t=–25 days, has been estimated for SN 1974g. By assuming the broad emission feature observed at 6480 Å to be H, very rough estimates of the electron density and the mass of ionized hydrogen in the expanding supernova envelope are given. The total (observed) luminous energy of SN 1974g was 1051 erg.  相似文献   

12.
We present spectroscopic and photometric observations of the peculiar Type II supernova (SN) 1998A. The light curves and spectra closely resemble those of SN 1987A, suggesting that the SN 1998A progenitor exploded when it was a compact blue supergiant. However, the comparison with SN 1987A also highlights some important differences: SN 1998A is more luminous and the spectra show bluer continua and larger expansion velocities at all epochs. These observational properties indicate that the explosion of SN 1998A is more energetic than SN 1987A and more typical of Type II supernovae. Comparing the observational data with simulations, we deduce that the progenitor of SN 1998A was a massive star  (∼25 M⊙)  with a small pre-supernova radius  (≲6 × 1012 cm)  . The Ba  ii lines, unusually strong in SN 1987A and some faint II-P events, are almost normal in the case of SN 1998A, indicating that the temperature plays a key role in determining their strength.  相似文献   

13.
Following our hypothesis that each supernova (SN) event triggers star formation in the swept-up gas, so that newly formed stars inherit the elemental abundance pattern of individual SNe, we deduce the production sites and yields for r-process elements. We further show that a strong evidence for the origin of r-process nucleosynthesis products was just there in our backyard - supernova SN1987A -, and conclude that 20 M ⊙ SNe are the predominant production sites for r-process elements. This revised version was published online in September 2006 with corrections to the Cover Date.  相似文献   

14.
Basic characteristics of the “response” of underground neutrino detectors to the explosion of SN 1987A occurred on February 23, 1987, are presented. We discuss the evolution of our viewpoint on the interpretation of the results concerning the detection of neutrino radiation from the supernova over the past 20 years.  相似文献   

15.
It is argued that the neutrino bursts registered on February 23.316 UT, 1987 signalized the transition of a fresh-borne neutron star into a superdense state. The neutron star is supposed to be formed approximately five hours before at February 23.12 UT in the supernova SN 1987a in the Large Magellanic Cloud.  相似文献   

16.
A very low upper limit of 0.15 mÅ for the interstellar 6707 Å Lii line has been recently derived towards the SN1987a by Baade and Magain (1988). This value corresponds toN(Li)<1.4×1011 cm–2 and gives [Li/H]<5.4×10–11 assumingN(Hi)=2.6×1021 cm–2 for the hydrogen column density in the LMC towards SN1987a. This value is lower than the Li abundance found in the Population II stars and lower than the minimum abundance allowed in the framework of the standard Big-Bang theory. We indirectly estimate the Li depletion usingKi observations and show that a depletion of 1.2 dex is plausible. Therefore, an interstellar abundance [Li/H] as high as 0.8×10–9 cannot be excluded. Any improvement in the above-mentioned upper limit will place important constraints on current theories for lithium nucleosynthesis.High-resolution IUE spectra of the SN1987a have been analysed in search for IS 1362 ÅBii resonance lines. A minimum detectable equivalent width of 22 mÅ has been found, that impliesN(B)<1.2×10–12 cm–2 and [B/H]<4.7×10–10 cm–2, i.e., comparable to the solar value of [B/H]=4×10–10. This limit is the most stringent derived so far for an external galaxy, and suggests that the rate of spallation processes in the LMC has not been higher than in our own Galaxy.  相似文献   

17.
An equation is obtained for the cross section of a metal Weber cylinder for scalar gravitational waves, which are possible within the framework of the field theory of gravitation. It is shown that the signals detected by the Amaldi and Weber antennas during the explosion of supernova SN 1987A can be interpreted as the result of the action of scalar gravitational waves on solid-state detectors. The required energy of the gravitational waves is about 1 M⊙c2. Together with the observed excess (about 1 %) of gravitational radiation from the binary system containing the pulsar PSR 1913+16, the signals from SN 1987A are the second piece of observational evidence for the actual existence of scalar gravitational waves. The present-day, third-generation, solid-state antennas are capable of detecting scalar waves from events like SN 1987A at a distance up to 5 Mpc. The expected level of the signal from SN 19931 is about 7 mK. An experimental test of the longitudinal nature of scalar waves is possible using interferometric antennas based on free masses. Translated from Astrofizika, Vol. 40, No. 3, pp. 377–389, August, 1997.  相似文献   

18.
We investigate the possibility of detecting the circumstellar Na I D1,2 and Ca II H, K absorption lines in the spectra of type IIP supernovae at the photospheric phase. Our modeling shows that the Na I doublet lines will not be seen in the spectra of type IIP supernovae at moderate stellar wind densities, for example, characteristic of SN 1999em, while the rather intense Ca II lines with P Cyg profiles should be detectable. The same model is used to describe the circumstellar Na I and Ca II lines in the spectrum of SN 1998S, a type IIL supernova with a dense wind. We show that the circumstellar line intensities in this supernova are reproduced only if there is an ultraviolet excess that is mainly attributable to the Comptonization of supernova radiation in the shock wave.  相似文献   

19.
We investigate the evaporation and condensation of corundum and silicon carbide grains around the supernova SN1987A. We predict the time after outburst of the interaction of the condensed dust with pre-existing dust, with a view to undertaking observations with future instrumentation such as the Infra-Red Space Observatory.  相似文献   

20.
In this paper, the neutrino mass has been determined from SN1987a observation in a manner that the simultaneity of neutrino emission is not regarded as the starting point, but is itself defined through the analysis by Monte-Carlo simulation. The result is that the neutrino mass lies in 3–4 eV, possiblym v 3.6 eV. Neutrino luminosity variation and neutrino spectrum are also obtained. Comparison with theories gives further support to the mass determination, and also predicts the mass of progenitor star of SN1987a to be in the range of 12–25M .The project supported by the National Natural Science Foundation of China.  相似文献   

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