What is the similarity between the spectra of white dwarfs and the sun?

  • Context: Undergrad 
  • Thread starter Thread starter MMS
  • Start date Start date
  • Tags Tags
    Spectrum White dwarf
Click For Summary

Discussion Overview

The discussion revolves around the similarities between the spectra of white dwarfs and the Sun, exploring the implications of these similarities in terms of temperature and spectral characteristics. Participants delve into the nature of stellar evolution and the physical properties that contribute to spectral similarities.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest that the similarity in spectra is related to the temperature of the stars, with a proposed temperature of around 10,000 degrees for both.
  • Others argue that while there are similarities, most white dwarfs are significantly hotter than the Sun, which complicates the comparison.
  • A participant notes that the spectrum of a white dwarf primarily shows broad hydrogen lines, whereas the Sun exhibits weak and narrow hydrogen lines along with prominent sodium, calcium, and iron lines.
  • One participant emphasizes that the spectrum originates from the gas shell surrounding the star, indicating that the internal structures are quite different.
  • A reference to a site comparing the spectra of the Sun, a white dwarf, and a blue giant is provided, suggesting that the white dwarf's spectrum is closer to that of the blue giant but with broader lines.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the spectral similarities, with no consensus reached on the extent of these similarities or their implications. Some agree on the temperature aspect, while others highlight significant differences in spectral features.

Contextual Notes

There are unresolved questions regarding the definitions of spectral similarity and the specific conditions under which these comparisons are made. The discussion also reflects varying interpretations of spectral characteristics based on stellar evolution stages.

MMS
Messages
146
Reaction score
4
Hello,

I read at a couple of places about white dwarfs having a spectrum similar to that of the sun.
What does that mean or associate to?

Thanks in advance.
 
Astronomy news on Phys.org
MMS said:
read at a couple of places about white dwarfs having a spectrum similar to that of the sun.
What does that mean or associate to?

Sun is called yellow dwarf star and its on the way to become a white dwarf- perhaps have journey time left of the order of few billion years.
the spectrum of white dwarf has similarities because of temperature of the star.

it is burning about 600 million tonnes of hydrogen per second in its core -if they burn up then it turns into a red giant star a small sparkling jewel of a white dwarf star will remain. This tiny remnant will have a mass of around half that of our present Sun,
 
  • Like
Likes   Reactions: MMS
drvrm said:
Sun is called yellow dwarf star and its on the way to become a white dwarf- perhaps have journey time left of the order of few billion years.
the spectrum of white dwarf has similarities because of temperature of the star.

it is burning about 600 million tonnes of hydrogen per second in its core -if they burn up then it turns into a red giant star a small sparkling jewel of a white dwarf star will remain. This tiny remnant will have a mass of around half that of our present Sun,
Thanks for the reply.

So when it is said that a white dwarf has a similar spectrum as the sun, what is meant by that is that they have the same temperature?
 
MMS said:
white dwarf has a similar spectrum as the sun, what is meant by that is that they have the same temperature?

It should be of the same order of magnitude...nearly 10,000 degree
 
And bear in mind that the spectrum is light that comes from the shell of gas that clings to the surface of the star. That's what is similar in the two cases. You cannot see the interior of the star, and it is completely different in those two cases.
 
MMS said:
I read at a couple of places about white dwarfs having a spectrum similar to that of the sun

Where?

I find this surprising. Most, but not all, white dwarfs are significantly hotter than the sun. A white dwarf shows broad hydrogen lines and little else. The sun shows only weak and narrow hydrogen lines, but prominent sodium, calcium and iron lines.
 
For example, this site compares the spectra of the Sun, a white dwarf and a blue giant. The White dwarf's is closer to that of the blue giant's but with broader lines.
http://hubblesite.org/newscenter/archive/releases/2012/25/image/b/
 

Similar threads

High School Evolution of planetary system around a white dwarf
  • · Replies 0 ·
Replies
0
Views
2K
Undergrad Orbital distance increase during the white dwarf phase of the Sun
  • · Replies 1 ·
Replies
1
Views
1K
Undergrad What Prevents Electrons from Expanding Radially in White Dwarfs?
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad What is the Possibility of Habitable Planets Around Brown Dwarfs?
  • · Replies 6 ·
Replies
6
Views
4K
High School Planetary debris found in white dwarf atmospheres
  • · Replies 5 ·
Replies
5
Views
2K
High School Nature: "A massive white-dwarf merger product before final collapse"
  • · Replies 1 ·
Replies
1
Views
3K
Undergrad Nuclear reactions in the Sun and other topics on stars
  • · Replies 49 ·
2
Replies
49
Views
5K
High School Formation of Brown Dwarfs in filaments?
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad White dwarf Ultra-relativistic electrons
  • · Replies 9 ·
Replies
9
Views
3K
Undergrad What is the New White Dwarf Mass Limit?
  • · Replies 9 ·
Replies
9
Views
3K