M 97
M 97
The Owl Nebula M97 is one of the fainter objects in Messier's catalog, discovered by Pierre Mechain. In the description of this object, Messier also mentions two that he (or Mechain) have seen at the same time, but which he had not added in his printed catalog version of 1781 (printed 1784); as the description is obvious and he added positions by hand in his personal copy, we now know that he had observed the objects M108 and M109.
M97 is one of the more complex planetary nebulae. Its appearance has been interpreted as that of a cylindrical torus shell (or globe without poles), viewed oblique, so that the projected matter-poor ends of the cylinder correspond to the owl's eyes. This shell is enveloped by a fainter nebula of lower ionization. The mass of the nebula has been estimated to amount 0.15 solar masses, while the 16 mag central star is believed to be of about 0.7 solar masses. Its dynamical age is about 6,000 years. (from Stephen J. Hynes, Planetary Nebulae).
The DSSM image of M97 reveals that in the background of this nebula, there are several small nebulous objects, most probably very distant galaxies, the brightest of these objects being superimposed by the brighter star above and slightly left of M97. This brightest background objects can be found on many larger-field exposures of the Owl Nebula.
| Right ascension | 11 : 2.0 (hours : minutes) |
|---|---|
| Declination | +55 : 18 (degrees : minutes) |
| Distance | 2.6 (light-years*10^3) |
| Visual magnitude | 12.0 |
