The Optical Appearance of a Star that is Collapsing Through its Gravitational Radius
Abstract
An analysis is presented of the radiation received by a distant observer viewing the late stages of gravitational collapse of a non-rotating, spherically symmetric star. The spectral distribution is calcu- lated as a function of time and of position on the apparent disk of the star; and the spectral properties of the total, integrated radiation are discussed. Among the conclusions are these: The star is brightest and bluest at its rim, where the spectrum and the intensity are independent of time; but the width of this time-independent region decays exponentially. Nearer the center of its disk, the star appears darker and redder; the redshift increases exponentially in time, and the intensity decays exponentially. The total, integrated radiation is dominated by the contribution from the rim: The spectrum is nearly time-inde- pendent and is peaked at its high-frequency end; but the total luminosity decays exponentially with time
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 1968
- DOI:
- 10.1086/149465
- Bibcode:
- 1968ApJ...151..659A