From here - http://www.fintech.co.jp/etc-data/hakka-tenn-data.htm So it's looks like 451C is not much better than 451F. But since autoignition depends on dencity if book in '55 were made from very inexpensive, low-grade paper 451F could be true.

Several Internet contrarians claim that Bradbury confused Celsius and Fahrenheit, putting his estimate off by 391 Fahrenheit degrees. They cite as evidence the Handbook of Physical Testing of Paper, which lists paper’s ignition temperature as 450 degrees Celsius. (Wikipedia cites the same source.) It’s not entirely clear how this number was arrived at, but it is an extreme outlier. The author appears to have used paper made with rayon or cotton, which could have a different auto-ignition temperature from pure wood pulp paper, but 450 degrees Celsius still sounds wrong. It’s also possible that the experimenters didn’t wait long enough or that they (and not Bradbury) switched Celsius and Fahrenheit.

Ignition temperature is the temperature at which something catches fire and burns on its own. The ignition temperature of paper is 451 degrees Fahrenheit, or 233 degrees Celsius.

у меня есть только микроволновка, которая в конвекции до 220 выдает, так что увы. 233 градуса дома мне к сожалению не получить