{'fraction_non_alphanumeric': 0.024171888988361683, 'fraction_numerical': 0.0, 'mean_word_length': 4.853403141361256, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Let It Flow.

Neutron stars arise from the gravitational collapse of massive stars during a supernova event. Most are thought to form via one of two mechanisms, each associated with a different type of supernova: iron-core collapse or electron capture. However, attempts to distinguish the two groups by examining the resulting neutron stars have not yet been successful. A magnetized neutron star in orbit with a companion can, however, constitute a powerful source of X-rays, and such X-ray pulsars may hold the key to telling apart the two types of neutron star — as Christian Knigge and colleagues now show. They have examined data for a large, well-characterized class of pulsar, and have identified a bimodality in the distributions of their spin and orbital periods, and of their orbital eccentricities. Shorter periods and lower eccentricity, they say, are likely to be associated with supernovae that were initiated through electron capture by neon and magnesium nuclei in a lower-mass stellar core, rather than those created when a high-mass star’s degenerate iron core tips over the Chandrasekhar limit. AK