What Ionizes the Gas in a Planetary Nebula (See the Image

question 35

Multiple Choice

What ionizes the gas in a planetary nebula (see the image below) and makes it visible?

• A) X-ray photons emitted by a pulsar
• B) ultraviolet photons emitted by a white dwarf
• C) the shock wave from a supernova
• D) hydrogen burning in the nebular gas

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Definitions:

DSM-5

The 5th edition of the Diagnostic and Statistical Manual of Mental Disorders, a standardized classification system for diagnosing mental disorders used by mental health professionals in the U.S.

Histrionic

Relates to a pattern of excessive emotionality and attention-seeking behavior; often associated with Histrionic Personality Disorder.

DSM-IV-TR

The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision; a manual used to diagnose mental disorders.

Cluster A

Refers to one of three clusters of personality disorders in the DSM, characterized by odd or eccentric behaviors, including paranoid, schizoid, and schizotypal personality disorders.