Are almost all stars in the night sky brighter than the Sun?

[wolf1728]

I was thinking about adding another page to my website concerning the nearest stars, the brightest stars, etc. In a list of the nearest stars, the vast majority are brighter than the Sun. (I looked for stars with an absolute magnitude that was greater than the Sun's (4.85) and had a visual magnitude less than 6.) Such stars are not well-known and among them are:
alpha Centauri B
epsilon Eridani
61 Cygni A
tau Ceti

Does anyone know if there is a statistic for this? (I doubt I'm the first one of think of this.)

 

[russ_watters]

I found this:
http://astro.unl.edu/classaction/questions/stellarprops2/ca_stellarprops2_lumfuncsun.html

I actually thought the sun was more average...

 

[Drakkith]

In a list of the nearest stars, the vast majority are brighter than the Sun.

Huh? Wikipedia's list of nearest stars and brown dwarfs has only three out of around fifty that are brighter than the Sun. Are you looking at only the stars that can be seen visually?

I actually thought the sun was more average...

Nope. The vast majority of stars are smaller and dimmer than the Sun.

 

[DaveC426913]

Nope. The vast majority of stars are smaller and dimmer than the Sun.

The link Russ posted seems to suggest otherwise. Though I think the issue is one of sampling. They mention the sun's neighborhood.

 

[Drakkith]

The link Russ posted seems to suggest otherwise. Though I think the issue is one of sampling. They mention the sun's neighborhood.

That's not how I'm reading that graph. Larger numbers are dimmer, right?

 

[DaveC426913]

That's not how I'm reading that graph. Larger numbers are dimmer, right?

Ah. My bad.
I assumed absolute mags would be positively increasing.

 

[wolf1728]

Drakkith you asked "Are you looking at only the stars that can be seen visually?"
Yes - geez I should have stated that question more clearly.
Apparently, this site does not like long questions so I kept editing my question until it "fit", thereby editing out the part about "stars of visual magnitude".

 

[russ_watters]

That's not how I'm reading that graph. Larger numbers are dimmer, right?

Hehe - while what I posted was vague enough not to be wrong, I read it backwards! D'oh!

 

[russ_watters]

Apparently, this site does not like long questions so I kept editing my question until it "fit", thereby editing out the part about "stars of visual magnitude".

You mean the title of the thread? That should just be a brief subject: the detailed question should be in the post.

 

[wolf1728]

Yes, I did ask in the posting (I looked for stars with an absolute magnitude that was greater than the Sun's (4.85) and had a visual magnitude less than 6.) but it would have helped if the topic title (or thread title is stated clearly).

 

[Fervent Freyja]

Maybe this will help. It includes some charts, gives useful instruction, and is loaded with plenty of resource links:

http://pumas.jpl.nasa.gov/files/03_05_10_2.pdf

"Studies of a Population of Stars: How Bright Are the Stars, Really?
OBJECTIVE: Make night sky observations of star brightness and color and use available data and simple calculations to correlate these observations with the characteristics of stars. In this activity, the distances to bright stars are calculated. The apparent brightnesses of these stars are then adjusted for distance to see which stars are intrinsically bright and which only appear bright because of their proximity to Earth."

 

[Janus]

Yes, I did ask in the posting (I looked for stars with an absolute magnitude that was greater than the Sun's (4.85) and had a visual magnitude less than 6.) but it would have helped if the topic title (or thread title is stated clearly).

If I understand your question correctly, you are asking if the vast majority of the naked-eye visible stars we see in the night sky are more luminous than the Sun. The answer is yes. Our sun would only be naked eye visible (have a visual magnitude of >6) if its distance was less than 55.33 ly away. The vast majority of stars we see in the sky are further away than that.
However, most actual stars are dimmer than the Sun.
For instance, here are two images, one shows all the naked-eye visible stars within 17.75 ly from Earth, the other shows all the stars in that same volume (50)
Our Sun is in the center of this image.

Stars visible mag <6

All stars

 

[snorkack]

Within 10 pc, the stars brighter than +6 and absolute magnitude dimmer than Sun are:
(Not Alpha Centauri B, because not resolved from A which is brighter than Sun)

1. Epsilon Eridani 3,72/6,18
2. 61 Cygni AB about 4,8/7,49+8,31, dimmest visible star
3. Epsilon Indi 4,69/6,89
4. Tau Ceti 3,49/5,68, brightest star dimmer than Sun
5. Omicron Eridani 4,43/5,92
6. 70 Ophiuchi 4,24/5,71
7. Sigma Draconis 4,67/5,87
8. 36 Ophiuchi ABC about 4,2/6,18+6,22+7,45
9. 82G Eridani 4,26/5,35
10. Xi Bootis AB about 4,6/5,59+7,84
11. Gliese 105 5,79/6,50
12. HD 4628 5,74/6,38
13. 107 Piscium 5,24/5,87
14. Mu Cassiopeiae 5,17/5,87
15. P Eridani AB about 5,1/6,27+6,40
16. 61 Virginis 4,74/5,09
17. G Arae 5,55/5,83
18. HD 192310 5,73/6,00
19. Kappa1 Ceti 4,84/5,03
20. HD102365 4,89/5,06
21. 61 Ursae Majoris 5,31/5,41
22. HR 4458 5,96/6,06
23. 12 Ophiuchi 5,77/5,82

 

[wolf1728]

Well those were very good replies (especially, snorkack's list of 23 stars).
There are about 6,000 stars visible in the night sky. (apparent magnitude 6 or brighter).
Then, it's safe to say that of all the stars that can be seen with the unaided eye in the night sky, more than 99% of those are brighter than the Sun.
Thanks again everyone.

 

[newjerseyrunner]

That makes sense, while most of the stars in the universe are smaller and dimmer than the sun, the ones that are visible to us will obviously be brighter. Barnard's Star, one of the closest to us isn't visible at all with the eye.

 

[snorkack]

Continuing the list past 10 pc

1. HR 511 5,63/5,64
2. Alpha Mensae 5,08/5,05
3. 54 Piscium 5,88/5,65
4. 11 Leonis Minoris 5,40/5,16
5. Zeta1 Reticuli 5,53/5,11
6. 85 Pegasi 5,81/5,34
7. 55 Cancri 5,96/5,47
8. HD 69830 5,95/5,45
9. HD 104304 5,54/4,99
10. HD 172051 5,85/5,28
11. 58 Eridani 5,63/5,01
12. HD 166 5,92/5,23
13. Pi1 Ursae Majoris 5,63/4,86
14. Psi Serpentis 5,86/5,03
15. HD 4391 5,80/4,93

That´s up to 15 pc. Total 38.
Checking the list for the range 15 to 17 pc is a bit more complicated, need a different source.

 

[Janus]

Within 10 pc, the stars brighter than +6 and absolute magnitude dimmer than Sun are:
(Not Alpha Centauri B, because not resolved from A which is brighter than Sun)

1. Epsilon Eridani 3,72/6,18
2. 61 Cygni AB about 4,8/7,49+8,31, dimmest visible star
3. Epsilon Indi 4,69/6,89
4. Tau Ceti 3,49/5,68, brightest star dimmer than Sun
5. Omicron Eridani 4,43/5,92
6. 70 Ophiuchi 4,24/5,71
7. Sigma Draconis 4,67/5,87
8. 36 Ophiuchi ABC about 4,2/6,18+6,22+7,45
9. 82G Eridani 4,26/5,35
10. Xi Bootis AB about 4,6/5,59+7,84
11. Gliese 105 5,79/6,50
12. HD 4628 5,74/6,38
13. 107 Piscium 5,24/5,87
14. Mu Cassiopeiae 5,17/5,87
15. P Eridani AB about 5,1/6,27+6,40
16. 61 Virginis 4,74/5,09
17. G Arae 5,55/5,83
18. HD 192310 5,73/6,00
19. Kappa1 Ceti 4,84/5,03
20. HD102365 4,89/5,06
21. 61 Ursae Majoris 5,31/5,41
22. HR 4458 5,96/6,06
23. 12 Ophiuchi 5,77/5,82

And for comparison, there are a total of 47 stars within that same distance, which have a visible magnitude of <6, which means that 14 of them have absolute magnitudes brighter than the Sun. This is out of a total of 184 total known stars in that same volume.

 

[Janus]

Continuing the list past 10 pc

1. HR 511 5,63/5,64
2. Alpha Mensae 5,08/5,05
3. 54 Piscium 5,88/5,65
4. 11 Leonis Minoris 5,40/5,16
5. Zeta1 Reticuli 5,53/5,11
6. 85 Pegasi 5,81/5,34
7. 55 Cancri 5,96/5,47
8. HD 69830 5,95/5,45
9. HD 104304 5,54/4,99
10. HD 172051 5,85/5,28
11. 58 Eridani 5,63/5,01
12. HD 166 5,92/5,23
13. Pi1 Ursae Majoris 5,63/4,86
14. Psi Serpentis 5,86/5,03
15. HD 4391 5,80/4,93

That´s up to 15 pc. Total 38.

Which is out of a total of ~71 stars of <6 visual magnitude from 10 to 15 pc or a total of 118 <6 magnitude stars and a total of 513 stars in all.

 

[Janus]

It's funny, another post sent me off on a tangent which led to me creating the images I posted above. They are single frames from an animation I was working on. I wasn't sure where I'd find a use for it, and then this thread starts. I just finished loading the video to YouTube. It isn't as clear as the images and in the upload, the colors were washed out, (the colors were to show the actual black body colors of each star by spectral class, and I put quite a bit of work into converting black body temp to RGB values and entering them for each individual star, so this bummed me out a bit.), but at least the brightness of the stars still represents absolute magnitude.
It starts out with just the stars of <6 visual magnitude and then brings in all 50 stars.

 

[snorkack]

And for comparison, there are a total of 47 stars within that same distance, which have a visible magnitude of <6, which means that 14 of them have absolute magnitudes brighter than the Sun.

Um... 24?

1. Alpha Centauri AB -0,27/4,34+5,71
2. Sirius -1,46/1,42
3. Procyon 0,34/2,65
4. Altair 0,76/2,20
5. Eta Cassiopeiae 3,46/4,59
6. Delta Pavonis 3,55/4,62
7. Beta Hydri 2,82/3,45
8. Vega 0/0,58
9. Fomalhaut 1,17/1,74
10. Pi3 Orionis 3,19/3,67
11. Chi Draconis AB 3,57/4,15+6,14
12. Mu Herculis 3,42/3,80
13. Beta Canum Venaticorum 4,24/4,63
14. Zeta Tucanae 4,23/4,56
15. Chi1 Orionis 4,23/4,70
16. Xi Ursae Majoris AB 3,79/4,25+5,07
17. Gamma Leporis A 3,59/3,83
18. Delta Eridani 3,52/3,74
19. Beta Comae Berenices 4,23/4,42
20. Gamma Pavonis 4,23/4,39

That´s it. My list does not match yours.
Note that out of the 20, 9 have absolute magnitudes over +4,10. The significance of that threshold being that it is double the brightness of Sun.
My list of 23 contains 6 stars with absolute magnitudes under 5,60. Which is half the brightness of Sun.

 

[marcus]

Well those were very good replies (especially, snorkack's list of 23 stars).
There are about 6,000 stars visible in the night sky. (apparent magnitude 6 or brighter).
Then, it's safe to say that of all the stars that can be seen with the unaided eye in the night sky, more than 99% of those are brighter than the Sun.
Thanks again everyone.

I can't tell but you might be missing the crucial fact that the "absolute magnitude" scale is backwards---a higher magnitude number means dimmer (not brighter).
If not, fine. This may be obvious but it hasn't been explicitly mentioned in the thread so just in case any reader is confused I'll say it.
Really really bright objects have to have NEGATIVE absolute magnitude numbers.
==quote Wikipedia https://en.wikipedia.org/wiki/Absolute_magnitude ==
A difference of 1.0 in absolute magnitude corresponds to a difference of 2.512 ≈ 100^.4 of absolute brightness.
==endquote==
Therefore a star of magnitude 2 is 2.512 times brighter than a star of magnitude 3, in output watts that is.
and therefore a star of magnitude -2 is 100 (or 2.512⁵) times brighter than a star of magnitude 3.
The abs mag 2 star is about 2.5 time brighter than the abs mag 3 star, in terms of real wattage output.
So brightness (watts) is NOT the same as magnitude

FWIW here are some figures from Wikipedia on APPARENT magnitude.
−0.27 The total magnitude for the Alpha Centauri AB star system. (Third-brightest star to the naked eye)
−0.04 Fourth-brightest star to the naked eye Arcturus[21]
−0.01 Fourth-brightest individual star visible telescopically in the sky Alpha Centauri A
+0.03 Vega, which was originally chosen as a definition of the zero point[22]
+0.50 Sun as seen from Alpha Centauri

So the sun is a dimmer star than Alpha Centauri A. At their separation distance Sun has apparent magnitude 0.5 while Alpha Centauri A has apparent magnitude close to zero---i.e. is brighter, more wattage.
I see that VEGA was originally chosen to be the standard zero on the apparent magnitude scale.

 

[Janus]

Um... 24?

right, 24. Though not really, check below)

1. Alpha Centauri AB -0,27/4,34+5,71
2. Sirius -1,46/1,42
3. Procyon 0,34/2,65
4. Altair 0,76/2,20
5. Eta Cassiopeiae 3,46/4,59
6. Delta Pavonis 3,55/4,62
7. Beta Hydri 2,82/3,45
8. Vega 0/0,58
9. Fomalhaut 1,17/1,74
10. Pi3 Orionis 3,19/3,67
11. Chi Draconis AB 3,57/4,15+6,14
12. Mu Herculis 3,42/3,80
13. Beta Canum Venaticorum 4,24/4,63
14. Zeta Tucanae 4,23/4,56
15. Chi1 Orionis 4,23/4,70
16. Xi Ursae Majoris AB 3,79/4,25+5,07
17. Gamma Leporis A 3,59/3,83
18. Delta Eridani 3,52/3,74
19. Beta Comae Berenices 4,23/4,42
20. Gamma Pavonis 4,23/4,39

That´s it. My list does not match yours.
Note that out of the 20, 9 have absolute magnitudes over +4,10. The significance of that threshold being that it is double the brightness of Sun.
My list of 23 contains 6 stars with absolute magnitudes under 5,60. Which is half the brightness of Sun.

Going over our lists, this is the comparison I got. Below Is my list. Blue represent stars with an absolute magnitude brighter than the Sun, and seems to match up with yours. The red highlighted stars are ones that are on my list but not yours (we used different designations for some stars, but I was able to cross-match.)
All 4 are dimmer than the Sun stars (which is Why I came up with 24 rather than 20; I didn't check my list of dimmer stars against yours.).
I queried the Hipparcos Main Catalogue, using the VizieR system, setting the constraints to <6 visual magnitude and >100 milliarcseconds of parallax. The system only listed the visual magnitude and I had to calculate the absolute mag from that and the parallax.
alpha Centauri A -0.01/ 4.34
Sirius (Alpha Canis Majoris) -1.44/ 1.45
Epsilon Eridani b 3.72/ 6.18
61 Cygni 5.2/ 7.49
Procyon( Alpha Canis Minoris) 0.4/ 2.68
Episilon Indi 4.69/ 6.89
Tau Ceti 3.49/ 5.68
40 Eridani 4.43/ 5.92
70 Ophiuchi 4.03/ 5.50
Altair( Alpha Aquilae) 0.76/ 2.20
Sigma Draconis 4.67/ 5.87
Gliese 570(33 G. Librae) 5.72/ 6.86
Eta Cassiopeiae 3.46/ 4.59
36 Ophiuchi 4.33/ 5.44
Gliese 783(279 G. Sagittaii) 5.32/ 6.41
82 G. Eridani 4.26/ 5.35
Delta Pavonis 3.55/ 4.62
BD+56 2966 5.57/ 6.50
Xi Bootis 4.54/ 5.41
Gliese 667(142 G. Scorpii) 5.91/ 6.69
Gliese 105(268 G.Ceti) 5.79/ 6.50
96 G. Piscium 5.74/ 6.38
107 Piscium 5.24/ 5.87
Beta Hydri 2.82 3.45
Mu Cassiopeiae 5.17/ 5.78
Fomalhaut(Alpha Piscis Austrini) 1.17/ 1.74

Vega(Alpha Lyrae) 0.03/ 0.58

Tabit(Pi3 Orionis) 3.19/ 3.67

Chi Draconis 3.55/ 4.02
p Eridani 5.76/ 6.21
Chara(Beta Canum Venaticorum) 4.24/ 4.63

Mu Herculis 3.42/ 3.80
61 Virginis 4.74/ 5.09
Zeta Tucanae 4.23/ 4.56

Chi1 Orionis 4.39/ 4.70
41 G.Arae 5.47/ 5.75
Gliese 785 5.73/ 6.00
Gamma Leporis 3.59/ 3.83

Delta Eridani 3.52/ 3.74

Beta Comae Bernices 4.23/ 4.42
Kappa 1 Ceti 4.84/ 5.03
Gamma Pavonis 4.21/ 4.39
66 G. Centauri 4.89/ 5.06
289 G. Hydrae 5.96/ 6.06
61 Ursae Majoris 5.31/ 5.41
12 Ophiuchi 5.77/ 5.82
Gliese 75 5.63/ 5.64

 

[marcus]

...
Note that out of the 20, 9 have absolute magnitudes over +4,10. The significance of that threshold being that it is double the brightness of Sun...

I don't follow. Wiki says the absolute magnitude of the Sun is 4.83
If something has abs mag MUCH over 4, say it has abs mag 5, then it would be LESS BRIGHT than the sun. If abs mag 6, then even dimmer.
can someone explain? are we using different terminology.

greater magnitude means dimmer, apparent magnitude takes account of the distance, absolute magnitude is what it would be at a standard distance of 10 parsecs. so if the distance is more than 10 parsecs (32.6 LY)
and you see two numbers like "4,10" the second number is probably the apparent magnitude (dimmer because farther away)

 

[wolf1728]

marcus, I would assume that when a number is written such as "4,10" (as snorkack did in his lists) it is just one number and not two and it actually means 4.10.
Anyway, since snorkack went through so much wok, I figured I'd combine both lists and put those on my website:
http://www.1728.org/starsvis.htm

 

[rootone]

Most of the stars visible to the naked eye are brighter than the Sun.
However most stars are less bright than the Sun.

 

[snorkack]

right, 24. Though not really, check below)
Going over our lists, this is the comparison I got. Below Is my list. Blue represent stars with an absolute magnitude brighter than the Sun, and seems to match up with yours. The red highlighted stars are ones that are on my list but not yours (we used different designations for some stars, but I was able to cross-match.)
All 4 are dimmer than the Sun stars (which is Why I came up with 24 rather than 20; I didn't check my list of dimmer stars against yours.).

Gliese 570(33 G. Librae) 5.72/ 6.86

Gliese 783(279 G. Sagittaii) 5.32/ 6.41

BD+56 2966 5.57/ 6.50

All were my mistakes of not noticing. Sorry about that.

Gliese 75 5.63/ 5.64

This I have in my list just after 10 pc.

 

[tony873004]

Here's an animation I made of a trip from the Sun to Orion.
notice how many dim stars fade into view and get passed before the familiar shape of the asterism begins to deform.
This implies that most close stars are too faint to be seen with the naked eye.

 

[snorkack]

That makes sense, while most of the stars in the universe are smaller and dimmer than the sun, the ones that are visible to us will obviously be brighter.

This is true, but not obvious.
To the contrary, it is a significant observation about Milky Way and solar neighbourhood.
Looking to the brightest stars...
Out of the 92 brightest stars of the sky, up to +2,50, all of them are brighter than Sun as mentioned. (Alpha Centauri B would be 21st if it were resolved, which it is not). In face, the brightest star in sky to be dimmer than Sun, Tau Ceti, is about 290th place.
Now, the nearest and dimmest of these 92 is Alpha Centauri AB.
6 of the 92 are within 25 ly of the Sun: Alpha Centauri, Sirius, Procyon, Altair, Vega, Fomalhaut.
The median distance, to 46th of the 92, is 170 ly.
The most distant 6, understandably at hard to know distances (too far for parallax) are over 1100 ly - the most distant being guessed to be Deneb Cygni estimated at 2600 ly.
If you look at the colour of these stars, the result is:
4 O stars
30 B stars
20 A stars
...making up 54 stars. All of these are massive young stars.
The remaining 38?
8 F stars, only 1 of which is arguably a dwarf
around 2 G stars, significantly double (Alpha Centauri and Capella)
and then about 20 K stars and 6 M stars, all of which are giants or supergiants.
Looking at distances again, 3 nearest giants are Pollux at 34 ly, Arcturus at 37 ly and Capella at 42 ly.
Then, within 100 ly of Earth, the 92 brightest stars include further 7 K and 1 M giant. The same distance, up to 100 ly, includes the 1 G dwarf, 1 arguable F dwarf (Procyon which may be subgiant), 1 F giant (Beta Cassiopeiae) - the rest are 16 A stars and 5 B stars.
What are these 11 nearby giants?
Capella is a double, so its masses are known - and happen to be big.
Whereas Arcturus, though single, is alleged to be low mass old stars.
Many of the remaining 9 simply have no mass alleged - understandably, as they are single.

How common, among the giants in solar neighbourhood, are young massive stars at the end of their short life, compared to lower mass stars at the end of a long life?

 

[wolf1728]

I added the 4 additional stars that Janus found
Gliese 570
Gliese 783
BD+56 2966
Gliese 75
to the web page I previously posted
http://www.1728.org/starsvis.htm
So, if I have followed everything correctly, that should now be a list of 42 stars.
And since I was given the apparent magnitude and absolute magnitude, I calculated the distance for all of those stars.
The most distant star in that list is HD 4391 at 48.7 light years.

 

[wolf1728]

Okay, it seems that the list goes out to a distance of 48.7 light years. If we want to make this an inclusive list, we'd have to make sure that all stars up to 55.3 light years have been checked. (If any of you know of a URL where I could search, I'd be glad to research the list out to 55.3 light years).
Snorkack, in the "comments" column, the comment for 61 Cygni AB says that it is "the dimmest visible star". What exactly did you mean by that? Wouldn't the dimmest visible star be magnitude 6.0?

 

[snorkack]

Snorkack, in the "comments" column, the comment for 61 Cygni AB says that it is "the dimmest visible star". What exactly did you mean by that? Wouldn't the dimmest visible star be magnitude 6.0?

It has the largest absolute magnitude of any star with visual magnitude under 6,0. All other visible stars are intrinsically brighter.
A complicating factor is that it is significantly binary. Addition of magnitudes is an inconvenient thing (raise to fractional power, add, then take a logarithm), so doing it by heart I preferred to round to one significant number and mentioned the approximateness in my list.
Check the distances to the binaries in my list. I systematically quoted the combined magnitude for apparent magnitude, because this is what eye sees (the binaries being not resolved by eye) and then the separate magnitudes for components (because this, like the true distance, is the truth out there).

 

[wolf1728]

In my list I added the comment "by absolute magnitude."
(Though I didn't mention this in the comments, 61 Cygni is significant for being the first star to have its distance accurately measured). (Bessel in 1838).
As far as the distances in the list, my only source was using the formula:
distance (parsecs) = 10^((m -M + 5)/5)

 

[Janus]

Here's a graphic I cobbled together that shows all the stars,including individual the members of multiple star systems( with the the exception of the "pup''(Sirius b) as it is too small to show up at the scale I used.) out to 6 parsecs.
Left to right is distance in parsecs. The blue vertical lines are absolute magnitude. The stars are shown to scale in size and the colors are their visible blackbody color. (or at least as close as I could get by converting star temp to RGB values)
I might try to continue it on past 6 parsecs, but I'm already running into information gaps. I had to quesstimate the radii of some of the smaller red dwarfs based on their temp and absolute magnitude as I couldn't find any sources that listed the information. As I try to move further out, I'm sure that this will become the case more often.

 

[snorkack]

(Though I didn't mention this in the comments, 61 Cygni is significant for being the first star to have its distance accurately measured). (Bessel in 1838).
As far as the distances in the list, my only source was using the formula:
distance (parsecs) = 10^((m -M + 5)/5)

Yes, but to the wrong magnitude.
The distance of 61 Cygni is 11,4 ly.
The visual magnitudes of components are +5,20 and +6,05, and the absolute ones +7,49 and +8,31 (I note errors in last numbers - these inconsistencies are common in quoted data). Since the components, with angular separation of 30 arc seconds, are not separated by eye, the combined magnitude is +4,8.

 

[wolf1728]

I changed the distance of 61 Cygni AB.
There are 42 stars in that list ending with a distance of 48.7 light years.
The limiting distance for a 4.85 absolute magnitude star to be visible is 55.3 light years.
Making an unscientific guess, if we were to extend that list to 55.3 light years, the number of stars would probably be less than 60.
Since there are about 6,000 stars that can be seen with the unaided eye, would it be safe to say that if you were to look at any star in the night sky, the probability would be greater than 99% that it is brighter than the Sun?