I know that the light coming from Proxima Centauri is not bright enough to make it naked-eye visible from the Earth. Is the Sun naked-eye visible from Proxima Centauri?
Welcome to Astronomy Stack Exchange
Astronomy Stack Exchange is a question and answer site for astronomers and astrophysicists. It's built and run by you as part of the Stack Exchange network of Q&A sites. With your help, we're working together to build a library of detailed answers to every question about astronomy.
We're a little bit different from other sites. Here's how:
Ask questions, get answers, no distractions
This site is all about getting answers. It's not a discussion forum. There's no chit-chat.
Just questions...
...and answers.
up vote
Good answers are voted up and rise to the top.
The best answers show up first so that they are always easy to find.
accept
The person who asked can mark one answer as "accepted".
Accepting doesn't mean it's the best answer, it just means that it worked for the person who asked.
Is the Sun visible from Proxima Centauri to human eyes?
up vote
14
down vote
asked Aug 24 '16 at 19:57
Patrick
4034 silver badges5 bronze badges
4034 silver badges5 bronze badges
2 Answers
up vote
4
down vote
accept
Alpha Centauri A and B happen to be rather similar to Sol, and their absolute magnitudes are 4.38 and 5.71 respectively (Wikipedia). Add them together and you get absolute magnitude 4.10 (the scale is logarithmic, and backward). Sol, with absolute magnitude 4.83, should look 0.73 magnitude dimmer than αCen at the same distance, so magnitude +0.46, quite bright.
answered Aug 25 '16 at 7:00
Anton Sherwood
2981 silver badge8 bronze badges
2981 silver badge8 bronze badges
up vote
3
down vote
The key to this is the so called Absolute Magnitude, which represents the visual magnitude from a distance of 10 parsecs (about 32 light years). The sun is much brighter than Proxima Centauri. It has an absolute magnitude of 4.8, and at a distance of 4 light years (the distance of Proxima), it would be be somwhat brighter than 1st mag, and so very easily visible with the unaided eye.
answered Aug 24 '16 at 20:29
Dr Chuck
3,7371 gold badge9 silver badges21 bronze badges
3,7371 gold badge9 silver badges21 bronze badges
Get answers to practical, detailed questions
Focus on questions about an actual problem you have faced. Include details about what you have tried and exactly what you are trying to do.
Ask about...
- Specific issues with astronomy
- Real problems or questions that you’ve encountered
- Experimental and theoretical problems in astronomy, astrophysics, cosmology, and planetary science
- Astronomical equipment, both professional and amateur
- The use of space probes, telescopes, and rovers for astronomical purposes
- Certain resource requests
Not all questions work well in our format. Avoid questions that are primarily opinion-based, or that are likely to generate discussion rather than answers.
Questions that need improvement may be closed until someone fixes them.
Don't ask about...
- Anything not directly related to astronomy
- Questions that are primarily opinion-based
- Questions with too many possible answers or that would require an extremely long answer
- Questions about physics or space exploration that do not involve astronomy (e.g. how a certain rocket works)
- Astrology or astronomy-related pseudosciences
Tags make it easy to find interesting questions
All questions are tagged with their subject areas. Each can have up to 5 tags, since a question might be related to several subjects.
Click any tag to see a list of questions with that tag, or go to the tag list to browse for topics that interest you.
Is the Sun visible from Proxima Centauri to human eyes?
up vote
14
down vote
I know that the light coming from Proxima Centauri is not bright enough to make it naked-eye visible from the Earth. Is the Sun naked-eye visible from Proxima Centauri?
asked Aug 24 '16 at 19:57
Patrick
4034 silver badges5 bronze badges
4034 silver badges5 bronze badges
You earn reputation when people vote on your posts
Your reputation score goes up when others vote up your questions, answers and edits.
+10
question voted up
+10
answer voted up
+15
answer is accepted
+2
edit approved
As you earn reputation, you'll unlock new privileges like the ability to vote, comment, and even edit other people's posts.
| Reputation | Privilege |
|---|---|
| 15 | Vote up |
| 50 | Leave comments |
| 125 | Vote down (costs 1 rep on answers) |
At the highest levels, you'll have access to special moderation tools. You'll be able to work alongside our community moderators to keep the site focused and helpful.
| 500 | Vote to close, reopen, or migrate questions |
|---|---|
| 1000 | Edit other people's posts |
| 2000 | Access to moderation tools |
Improve posts by editing or commenting
Our goal is to have the best answers to every question, so if you see questions or answers that can be improved, you can edit them.
Use edits to fix mistakes, improve formatting, or clarify the meaning of a post.
up vote
9
down vote
Alpha Centauri A and B happen to be rather similar to Sol, and their absolute magnitudes are 4.38 and 5.71 respectively (Wikipedia). Add them together and you get absolute magnitude 4.10 (the scale is logarithmic, and backward). Sol, with absolute magnitude 4.83, should look 0.73 magnitude dimmer than αCen at the same distance, so magnitude +0.46, quite bright.
answered Aug 25 '16 at 7:00
Anton Sherwood
2981 silver badge8 bronze badges
2981 silver badge8 bronze badges
The difference between magnitude 0.4 (your answer) and magnitude 0.46 (my answer) is accounted for by the distance between Proxima and Alpha A/B, which I ignored for simplicity. It's not a factor of 1.4. - Anton Sherwood Aug 27 '16 at 3:56
Unlock badges for special achievements
Badges are special achievements you earn for participating on the site. They come in three levels: bronze, silver, and gold.
| Student | First question with score of 1 or more |
| Editor | First edit |
| Good Answer | Answer score of 25 or more |
| Civic Duty | Vote 300 or more times |
| Famous Question | Question with 10,000 views |
Sign up to get started
Signing up allows you to:
- Earn reputation when you help others with questions, answers and edits.
- Select favorite tags to customize your home page.
- Claim your first badge: Informed
Looking for more in-depth information on the site? Visit the Help Center
Astronomy Stack Exchange is part of the Stack Exchange network
Like this site? Stack Exchange is a network of 177 Q&A sites just like it. Check out the full list of sites.
Use comments to ask for more information or clarify a question or answer.
You can always comment on your own questions and answers. Once you earn 50 reputation, you can comment on anybody's post.
Remember: we're all here to learn, so be friendly and helpful!