< Stars‎ | Os

O stars is a lecture about an entity, source, and/or object observed using radiation astronomy that is classified as an O-type star.

HD 93129 is surrounded by the lesser stars of Trumpler 14 star cluster. Credit: NASA & ESA, Jesús Maíz Apellániz (Centro de Astrobiología, CSIC-INTA, Spain).

You are free to take this quiz based on O stars. Once you've read and studied it, the links contained within, listed under See also, External links and the {{stars resources}} template, you should have adequate background to score 100 %.

Enjoy learning by doing!

Quiz edit


1 O stars can be put into classes based on?

apparent mass
spectral lines

2 Yes or No, Stellar class O stars have surface temperatures high enough that most of their luminescence is in the ultraviolet.


3 Which of the following is not a characteristic of O type stars?

can be a spectroscopic binary
the hottest stars
can be a high-velocity star
peak wavelength in the gamma-ray range
orange color.

4 True or False, Alnitak is a triple star system with an O9.7 supergiant and an O9 giant as well as a B0 giant.


5 True or False, Spectroscopically Zeta Puppis is classified as O4 I.


6 True or False, BI 253 is an O2V star in the Large Magellanic Cloud.


7 Gamma-ray stars have surface temperatures starting at 300,000,000 K (300 MK) corresponding to a peak wavelength of 0.010 nm (10 pm) for the beginning of super soft


8 True or False, X-ray stars have surface temperatures starting at 300,000 K corresponding to a peak wavelength of 10 nm for the beginning of super soft X-ray sources.


9 Which of the following is not a phenomenon usually associated with O-type SN progenitors?

a blue supergiant
an LBV
a red supergiant
an early W-R
a WN

10 Complete the text:

On the main sequence for spectral classes 06-06.5, 07, and 08 one finds strong

λ4686 absorption often accompanied by weak

λλ4634-4640-4642 emission.

11 True or False, In 1947, G. E. Kron proposed that starspots were the reason for periodic changes in brightness on blue dwarfs.


Hypotheses edit

  1. Stars that emit light do so because they are receiving electron irradiation.

See also edit

External links edit