Talk:Barnard's Star/Archive 1

Archive 1

In fiction

Barnard's star is mentioned in several science fiction stories (Dan Simmons' Hyperion Cantos comes to mind, but I can't remember the name of its planet). Please create a list of those stories on the article, if you remember any.--Jyril 12:25, 31 December 2005 (UTC)

Adding External Link

I have been imaging this star since 1997 and displaying the change of position every year.

The last time I added a link to an article I got spanked. Would someone please look at my web page to see if it is appropriate to add as an external link.

Link is: http://schmidling.com/barnard.htm

It also occurs to me that it would be useful to add a picture to the article as there are none and mine seem to be the only ones out there since the 50's. I am thinking of the color one from 2003 resized to fit neatly on the right.

Thanks, Jack Schmidling 04:57, 31 August 2006 (UTC)

Hi Jack. Regarding your site:

• Are you selling anything?

Site is a big word. Most of my pages are for public information but a few describe products we sell.

Don't seem to be, but I see the link to the brewery.

That page is supposed to be a joke.

• Are you advancing or attempting to debut research of your own? Again, doesn't seem so.
• Is it verifiable info? This is tricky. On the hand you can log in and tell everyone it is, but as it isn't attached to school, journal, etc. I don't think it qualifies.

Roger.

So I would say so no, but don't take it badly as the same would be true of any personal website. See here for more.

Re the picture idea, some of the links here do in fact have them, but your 2003 pic is indeed very excellent. If you're willing to release it under the GFDL you can upload and post in. You can use {{PD-self}} to tag it for copyright status. Note that it ceases to be "yours" at that point and is free for anyone to subsequently use without necessarily crediting it. Hope that helps. Marskell 14:12, 31 August 2006 (UTC)

After posting this I stumbled on the picture info and realized it was an inappropriate question.

I don't mind giving it to Wikipedia for the world to look at but this photo has been purchased by dozens of authors using it in for-profit pubs so I would not be inclined to give it away under those circumstances.

Thanks for your help,

Jack Schmidling 04:08, 1 September 2006 (UTC)

I thought the brewery seemed tongue-in-cheek ;). Marskell 10:47, 4 September 2006 (UTC)

ref

George D. Gatewood (1995). "A study of the astrometric motion of Barnard's star". Journal Astrophysics and Space Science. 223: 91–98. doi:10.1007/BF00989158. —The preceding unsigned comment was added by Stone (talk • contribs).

Thanks Stone. There appear to be three 80s, 90s refutations of planets. Harrington, "Status Report on an Intriguing Neighbor" (1987) for which I can't view an abstract, the one you provide from 1995, and the 1999 Hubble piece now in the article which confirms 1995.

With the van de Kamp story covered, I would also like to add a more general "Research" section. However, I'm an amateur and would appreciate any help with the hard science. I would like to note, for instance, to what mass and orbital values the null hypothesis on planets has been refined, and values under which planets are still possible. Marskell 14:46, 12 September 2006 (UTC)

GA review

• 1. Well-written: A few errors in one section, but very minor. I quickly fixed them. Otherwise, clear and interesting to read.
• 2. Factually accurate and verifiable: Excellent cites! Facts seem accurate.
• 3. Broad in coverage: Reasonably so. The Sci-fi usage that was spun off could be better linked.
• 4. NPOV: Didn't notice any opinions.
• 5. Stability: Reasonable.

Verdict: Pass! Congrats! Adam Cuerden ^talk 07:50, 15 September 2006 (UTC)

Thanks Adam for your friendly post and for taking the time to make edits yourself. However, I have removed the GA tag, for a couple of reasons. While I'd immodestly say that additions over the past two weeks are very good (it's a ref per k at the moment) the article as a whole only has 50 - 60% of the info needed. A research section, distinct from the planet controversy, is the obvious absence. Aside from this, I believe GA is a poorly defined process and I think the tag accomplishes little, particularly for an article which is being actively worked on. This article is about mid-way through a two to four week push to get it to FA standard (at least that's what I hope for); judging it now doesn't achieve much. If I am violating a policy by removing the tag, tell me so. Cheers, Marskell 12:07, 15 September 2006 (UTC)

I disagree rather strongly (as the person who nominated this article for GA status). All articles in wikipedia are (are should) be actively worked on so that distinction is, IMO, meaningless. Unless you think the article doesn't meet the GA criteria, I would request that you alow the tag to remain for the benefit of those who do consider it of value. Eluchil404 22:28, 15 September 2006 (UTC)

To reply specifically to "actively worked on", I have been told in various ways GA is an assessment rather than improvement drive. I meant that it makes little sense to assess an article when, for instance, a k/day is still being added. Marskell 07:20, 16 September 2006 (UTC)

Since the GA was awarded and not being contested, this is GA whether it has the tag or not, IMO. Restore the tag freely. Adam Cuerden ^talk 22:32, 15 September 2006 (UTC)

It doesn't do any harm to add it, if it bothers you—though as I say, I'd like to see a line of policy that says other contributors are not free to remove it.

As I've said elsewhere, given that the GA criteria are essentially identical to the FA criteria, by the time this is a GA it might as well as go to FAC. But no, this doen't meet the criteria. There is still too much absent. Marskell 04:05, 16 September 2006 (UTC)

Weel, it was requested on the GA page, so... Of course, I'm not an astronomer, so I might have missed some of the needed breadth, of course. Adam Cuerden ^talk 14:45, 15 September 2006 (UTC)

I'm not an astronomer either! In fact, I'd like a couple astronomers to look at how I'm incorporating stats. I just don't know that it means anything worthwhile to say "good article" at this point. But I don't want to denigrate your effort looking at it. If you happen to know any astronomers, tell them to check it out ;). Marskell 19:48, 15 September 2006 (UTC)

New Image

I think the new one I uploaded is better, feel free to revert if it is not.-- ¢² Connor K.   22:47, 15 October 2006 (UTC)

Notes

I think here's something wrong with the notes & references. Click the "1" after the "Barnard's Star" text above the first picture. This will revert you to the text: "SIMBAD is used for observation data, while ARICNS is used for astrometry. More specific numbers from research papers may be employed, but will also be mentioned in the body." This appears to have nothing to do with the simple text "Barnard's Star." Scholarus 03:03, 14 December 2006 (UTC)

The note refers to all of the data in the star table. Maybe this is confusing because it's not actually inside the box but above it... Marskell 04:14, 14 December 2006 (UTC)

Comparing the images

I'm trying to align the two images, the brighter one at the top and the animation at the bottom. Barnard's is currently passing by a star that is visible in the animation, and if you look carefully you can see a fainter star closer to it, but it only appears on some frames. Those two stars seem to line up with two in the upper image if you rotate the animation about 30 degrees clockwise. However the animation also features a rather prominent "arrow" in the upper left of the frame, and I can't seem to match that up with anything on the upper image. Does anyone know how to align them? Maury 13:05, 2 February 2007 (UTC)

Maybe leave a talk post Conner. He's the image man here. Marskell 13:31, 2 February 2007 (UTC)

Needs a copy-edit

Very interesting article, but in just brief browsing, a number of minor grammar and punctuation errors were apparent. I fixed a few, but am "edited out" for the moment, having recently finished c/e of another FAC and a would-be GA. Would suggest posting a request for c/e here -- probably a good idea for all FAC to have one. Regards, Unimaginative Username 02:11, 18 October 2007 (UTC)

Congrats!!

Congrats to featured article, fellow astronomy oriented wikipedians!! Said: Rursus ☻ 07:09, 18 October 2007 (UTC)

What the f* is this jabbering about?

The moon itself would never be brighter than Venus is now, and Venus would at best be a faint starlike object of magnitude +3.7. Jupiter would barely be visible to the naked eye; Mars and Mercury would usually be invisible, and Saturn would always be unseen. —Preceding unsigned comment added by 193.195.77.146 (talk) 06:58, 18 October 2007 (UTC)

No idea. Removed. Marskell 08:12, 18 October 2007 (UTC)

could we semi protect this page?

there is a lot of vandalism on it.--204.78.8.81 13:08, 18 October 2007 (UTC) The vandals are out and aboutBwthemoose 13:20, 18 October 2007 (UTC)

TYPO

It says "For a decade from 1763 onwards" - 1963 surely? I don't want to edit it if it's featured without confirmation.

82.26.86.109 —Preceding comment was added at 13:52, 18 October 2007 (UTC)

Explain star age

Although the star age is given as 7-12 giga-years (population II) with a good reference, it might be useful to briefly explain how this figure was arrived at, or link at that point to another article detailing how the age of stars is determined. --IanOsgood 05:03, 18 October 2007 (UTC)

I got that paper late yesterday and haven't gone through it. Will try. Marskell 08:15, 18 October 2007 (UTC)

The age of stars is determined by their position on the so-called Hertzsprung-Russell (H-R) diagram, which is a scatter-plot type diagram that depicts characteristics of a star's spectrum versus its absolute (that is its real, not apparent to a distant observer) luminosity. See http://en.wikipedia.org/wiki/H-R_Diagram. Elements of the scatter plot depict the so-called "main-sequence", (http://en.wikipedia.org/wiki/Main_sequence) which is a "snap-shot" depiction of the developments and characteristics of most stars during their lifetimes. The position of a star on the main sequence, along with the so-called spectral-type of the star (types are lettered O-B-A-F-G-K-M, and roman numbered, I - VII; our sun is typically regarded as a class G2V) which is indicative of the chemical composition of the star (determined by spectral emission and absorption lines), which for most of the lifetime of most stars is an indirect measure of a star's age, based on currently accepted models of the fusion processes that take place in stellar atmospheres.

I dont' know if this helps at all, of if you already know all of this. I hope it's helpful. I cannot vouch for the Wikipedia entries I have linked to as I haven't read them closely, but information on these subjects is the information one needs to explain how stars are assigned an age.

On a side note on this article I was rather annoyed to see that the ANIMATED image of Barnard's Star showing its proper motion over time (that is the real motion (relative to the motion of our sun of course) that this tiny star exhibits with respect to the distant background stars against which it is viewed) was removed. Proper motion is a very important subject in basic astronomy, and few people know that some stars can actually be shown to be moving about within our galaxy (and seen to be doing so within a human life-span), and photos over time can show this motion. Its a shame that fear has ruled the day here and the pictures have been removed. One of the most interesting aspects about Barnard's Star is its very large proper motion, and these images showed the basics of the idea better than a written article on the subject could alone.

Doesn't the notion of "fair comment" cover the use of these animated images, at least for the short period of time that the article on Barnard's Star was a "Feature Article." I wanted to show proper motion to my wife who works in a news room and likes to see visuals that explain scientific subjects, but by the time I returned to Wikipedia to show her, the animation was gone. Terrible shame. J.A.Ireland, BA (IHPST) 14:50, 18 October 2007 (UTC)

Redundancy

In the lead para, end of firs bit, it reads:

• • Despite its proximity, Barnard's Star is not visible with the unaided eye.
• I think it could sound better, like this:
  • Despite its proximity, it is not visible with the unaided eye.
• It doesnt over use the term Barnard's star, and it is clear that we are talking about that star, given the articles name. Thoughts? Twenty Years 14:34, 18 October 2007 (UTC)

The prior sentence discussed Alpha Centauri. I inserted this star's name in the sentence to avoid any ambiguity. — RJH (talk) 15:10, 18 October 2007 (UTC)

Check please ?

Can someone please check this content?[1] It was left after a series of vandal reverts, and I'm not sure where it came from or if it's accurate. SandyGeorgia (Talk) 16:52, 18 October 2007 (UTC)

Found the edit; don't know if it's reliable. SandyGeorgia (Talk) 17:02, 18 October 2007 (UTC)

These also need to be checked by someone who knows the topic. SandyGeorgia (Talk) 18:29, 18 October 2007 (UTC)

I assume the first is good faith, but it needs a footnote formula. On second, "favourable location" repeats the source. Thanks for all your reverts today! Marskell 18:56, 18 October 2007 (UTC)

VANDALISM

We need to put protection on here it vas vandalised now it is the feature article.141.155.148.181 20:26, 18 October 2007 (UTC)

backslash vandalism

Semi protection seems a good idea, for whatever reason, people like to vandalise articles about stars...?Ravenmasterq 16:00, 18 October 2007 (UTC)

I typically oppose protection of any sort as a matter of principle. Anyone can edit and all that. Marskell 16:10, 18 October 2007 (UTC)

I made such a suggestion on the constellations task force page a while back. Vandalism on the astronomy pages is getting out of hand, apparently from bored kids in their school IT room. GoogleSky is now (rightly) linking to these pages, but I don't think NASA, Google or professional educators would be impressed by some of the silly language or downright profanity that appears every day. This is devaluing the work put into Wikipedia by dedicated editors over a long period. I favour a system like that proposed by German Wikipedia in which only registered editors would be allowed to make immediately visible changes. All other changes would have a two-day "quarantine" period. This would preserve the principle of "anyone can edit" but discourage vandalism. And make life easier for those of us who are spending too much time on vandal watch. Skeptic2 17:14, 18 October 2007 (UTC).

PS: And while I was typing the above someone got in and vandalized the entry again. I think it's essential that we get WikiProject Astronomy to make a decision about protection of all the entries on constellations, stars and deep-sky objects. Skeptic2 17:22, 18 October 2007 (UTC)

This article has reached a level of vantalism so intense that it is moving beyond the ability of editors to combat it. Entire sections are going missing without people noticing.

Personally, I've always thought that no one should be allowed to edit Wikipedia until they bother to register. Of course, that's an entirely hypocritical position, as Marskell might well remember, since I spent my first few weeks on Wikipedia editing anonymously. But after two years of constant anonymous vandal edits, I've come to the conclusion that forcing people to take the time to register would cut down on "showoff" tagging. Serendi^podous 16:43, 18 October 2007 (UTC)

Do note that the vandalism rate is way up for the moment due to this being today's featured article. It should go down within twelve hours. Michaelbusch 17:26, 18 October 2007 (UTC)

True, but not an argument against the proposition! Skeptic2 18:51, 18 October 2007 (UTC)

WikiProject Astronomy can discuss all it wants, but it doesn't own the articles, and it can't decide that astronomy articles should be protected when it goes against the protection policy. 17Drew 18:54, 18 October 2007 (UTC)

I don't see that what we are proposing is necessarily against the Protection Policy. Surely we have a responsibilty to users of our material, no? Skeptic2 20:15, 18 October 2007 (UTC)

I usually find that a 'before' and 'three days later' history comparison of a front page FA is sufficient to track down any lingering vandalism in the article. In the past I was skeptical about this, but I often see very little vandalism left over. The editors and/or bots usually do a good job of cleaning up, and the remaining changes are mostly useful. My $.02 worth. — RJH (talk) 21:23, 18 October 2007 (UTC)

Concur. Quite often, an article ends up with almost no net change at all during its time on the front page. Just wait it out and everyone will be fine. —Wknight94 (talk) 21:26, 18 October 2007 (UTC)

I don't see anything remotely useful about the vandalism that's been happening today to Cassiopeia, Gemini, Puppis, Ursa Major, Constellation, maybe others that I haven't been keeping an eye on. You'll know that I am not a hard-line reverter, even with that pain we have had on the Sirius page recently, but I don't think that the philosophy of Wikipedia is best served by what we've seen recently. It isn't confined to the featured article and in my view it is getting worse (and will continue to do so). Skeptic2 21:39, 18 October 2007 (UTC)

PS - and add Capricornus to that list - I just rechecked my Watchlist after sending that mesage... Skeptic2 21:41, 18 October 2007 (UTC)

Nothing's going missing; nothing's getting lost. I'm the primary author and am aware of the page. Knowing RJ and Serendip are looking occasionally, I have no worries about this particular TFA. I appreciate the open dynamic, despite the vandalism. It allows people to test Wikipedia's interface and (even if it's just a stray comma) let's them improve things.

Conversely, if you have a page where there is no primary author still editing, perhaps it should be protected. Perhaps that could be the main criteria on this protection debate (it's not limited to this page). Marskell 22:07, 18 October 2007 (UTC)

Picture!

I found some pictures on NASA's website. I have found this quote.

NASA still images, audio files and video generally are not copyrighted. You may use NASA imagery, video and audio material for educational or informational purposes, including photo collections, textbooks, public exhibits and Internet Web pages. This general permission extends to personal Web pages.

I think it says I can use them! I will upload them, then put them on the site. Is that ok? If not, lemme know!-- ¢² Connor K.   23:41, 10 October 2006 (UTC)

Connor, I sent an e-mail to NASA this very day and suggest we wait. I don't believe their "generally not copyrighted" note should be used to upload anything with NASA in the address bar. The NASA site is massive, linking to many .edu type places, where the assumption of public domain does not seem right.

That said, I want pics as much as anybody! This page is great...the lack of pics is the only glaring absence. Marskell 00:07, 11 October 2006 (UTC)

THANK YOU SO MUCH FOR REPLYING. I was so close to biting the bullet and uploading it. I even went as far as to call them, only to get a voice-mail. I will try again tomorrow (on the phone), and if get through to someone, I will try to get them to verify that it is not copy-righted. Thanks for letting me know!-- ¢² Connor K.   00:15, 11 October 2006 (UTC)

I emailed them. They said it was fine to use in the article, I am going to upload it.-- ¢² Connor K.   18:51, 13 October 2006 (UTC)

Isn't NASA a US government agency, and isn't therefore anything they produce automatically free? —Preceding unsigned comment added by 24.86.252.26 (talk) 04:20, 19 October 2007 (UTC)

Improper AD to CE change

Why was "AD 11,800" improperly changed to "11,800 CE" in this edit? Gene Nygaard 21:31, 18 October 2007 (UTC)

I have reverted it in accordance with Wikipedia guidelines of primacy and added a reference from Patrick Moore's Book of Astronomy facts--AssegaiAli 10:10, 20 October 2007 (UTC)

Explain star age re: the Sun

The Sun is classified as a G2 main sequence (V) star, not "GII to GIV." A GII to GIV describes a G-type bright giant to subgiant, which is impossible. —Preceding unsigned comment added by 192.30.202.18 (talk) 21:50, 24 November 2007 (UTC)

Image sizes

As stated in the manual of style and accessibility guidelines, the sizes of image thumbnails should generally not be specified. I'll leave the images containing text alone, for the sake of readability but I'll remove sizes from the rest. Papa November (talk) 10:50, 20 January 2008 (UTC)

Category:Stars with proper names ?

I was thinking of putting this article in this category; but thought i would ask here first, anyone think it would be incorrect or correct to do this? Is it a proper name? Carlwev (talk) 17:55, 10 October 2008 (UTC)

Removed line

The following line was commented out in the article text; I've removed it for now:

The star is also known under the name Velox Barnardi, (Latin for "the Swift One of Barnard") or Barnard's Runaway as well.<ref>Also written with quotation marks. See e.g. [2]; [3]; [4], page 13.</ref>

Mike Peel (talk) 10:59, 25 December 2008 (UTC)

Possible error

There is some question in my mind about the correctness of the following statement:

"Barnard's Star is approaching the Sun so rapidly that it will become the nearest star around AD 11,700, at a distance of some 3.8 light-years.[15]"

In particular, see Matthews (1994) fig. 2. Reference 15 says that Barnard's star will approach within 1.144 parsecs, but it only provides a distance of closest approach, rather than asserting it will be the closest star. Per Matthews, during that same time period Proxima will move even closer, eventually moving within a parsec. Please correct this statement or provide a better reference. Thank you.—RJH (talk) 17:58, 5 February 2009 (UTC)

I modified the text accordingly. Sorry.—RJH (talk) 21:32, 5 February 2009 (UTC)

Date of nearest approach

This information is old, so now probably incorrect, but mentioning it 'just in case' - 'fraid someone with better knowledge than myself will have to check it ... in an article in the July 1981 edition of The Magazine of Fantasy and Science Fiction titled 'The Runaway Star' (later included in the collection 'Counting the Eons' ISBN 0-586-05843-5), Isaac Asimov says that its closest approach will be in 9800 years, a bit different from the figure mentioned in the article. Like I say, the Asimov information is probably wrong, but thought I'd mention it. Rhillman (talk) 14:37, 15 March 2010 (UTC)

Thanks. The Asimov figure is pre-Hipparcos, so the date of closest approach likely changed because of the refined astrometric information. I'm sure it will be further revised in the future as better measurements are made.—RJH (talk) 16:50, 15 March 2010 (UTC)

position

So this star is notable for moving 10 arcseconds per year. And this article gives its position to an accuracy of an arcsecond, but based on a 1997 reference. This is clearly useless. The position data needs to specify the date to which it applies.

If the position cited in the article is really the position of 1997, then the star has since moved away from it by 2 arc minutes. In other words, the implied accuracy to an arc second is phony and valid for exactly one month before it is obsolete. --dab (𒁳) 12:22, 19 January 2011 (UTC)

Unsourced text

The following text has been tagged as unsourced for close to two years, so I was bold and stripped it out:

Barnard's Star can be viewed directly overhead from just north of the equator, at 4° N; theoretically viewable ± 90° from this point, it can thus be observed at most Earth latitudes, although atmospheric extinction will reduce visibility when it is near the horizon in the extreme north and south.

Regards, RJH (talk) 15:17, 9 May 2011 (UTC)

Discovery?

This page says Barnard "discovered the proper motion" in 1916. Some sources say he discovered it, but 1916 seems a bit late to discover a ninth-magnitude star. Do we have any information on the discovery? Shimgray | talk | 23:38, 13 September 2006 (UTC)

You can view his paper: "I have found in my photographs a small star..."[5]. I thought it late too, but 1916 it appears to be. In fact, the sentence should read "The star and its large proper motion were discoverd..." Marskell 08:15, 14 September 2006 (UTC)

The star has a catalogue number in the Bonner Durchmusterung, which was published well before Barnard noted its unusual proper motion. Hence, I don't think we can claim Barnard "discovered it" as such. Regards, RJH (talk) 21:51, 13 February 2012 (UTC)

Drop the Inverse Radians.

At 5:19 on the 21st of May 2013 "(20,000 inverse radians)" was added to the article beside "10.3 arcseconds". What is an inverse radian? How can the inverse of an angular measure be equal to an angular measure? I think this should be dropped. If the proper motion were to be expressed in years per Radian It would be 20,000 years per radian, which seems to me a pointless sort of measure. The proper motion changes over time and would be different in 10,000 years. - Fartherred (talk) 02:08, 8 February 2015 (UTC)

Pioneer approach

I fail to see the relevance of Pioneer 10 approaching within 3.8 light years of Barnard's Star in 10,000 years since, in 9000 years, the Sun will apparently be 3.75 light years from Barnard's Star. So probes in heliocentric orbit (or Earth orbit, or sitting on a launchpad, or in mothballs) will be closer than Pioneer 10 will ever be. 135.23.85.212 (talk) 20:57, 1 January 2015 (UTC)

Yes we should drop the reference to Pioneer 10's approach. - Fartherred (talk) 02:08, 8 February 2015 (UTC)

I came here to explain why I was removing the bit about Pioneer 10 from the article... Well, it's gone now. Also note that the supporting reference was a book about Concorde - probably not a very reliable source for an astronomy article. 92.10.193.67 (talk) 03:58, 26 October 2015 (UTC)

Well, my edit seems to have been uncontroversial. (Yes, I'm the same person.) Anyway, it occurred to me that this deletion could be backed up by working out where in space Pioneer 10 will actually be in 10,000 years' time. Turns out it'll be about 0.4ly away from the Earth (if my sums are correct), and as for the direction... it's currently heading almost directly away from Barnard's Star. And of course when I looked up the Pioneer 10 article to check its heading, I discovered that the same nonsense is also in there. So I shall remove it. 78.146.214.216 (talk) 19:35, 11 November 2015 (UTC)

The math in citation 20 doesn't check out

Or I'm just being really dumb.

The moon is half a degree, or 31 arcminutes in diamteter. 31 arcminutes is 1860 arcseconds. Divide 1860 arcseconds by 10 arcseconds/year to get 186 years.

The average human lifespan is less than 186 years by quite a bit[citation needed], so there's an error in here somewhere. — Preceding unsigned comment added by 2601:602:9501:C2FF:757E:8001:4633:2378 (talk) 10:51, 5 December 2016 (UTC)

I see no problem with the calculation. It clearly states that the movement amounts to about a quarter of a degree in a human lifetime, and I think that is accurate. Equating a quarter of a degree to the angular diameter of the moon requires a bit of poetic license. As an order of magnitude comparison it is correct, but it is out by a factor of two. The article explicitly states that the movement is a quarter of a degree or about half the diameter of the moon, so no problem there. Feel free to find a reference that doesn't use any poetic license if you want. Lithopsian (talk) 14:02, 5 December 2016 (UTC)

The comparison with a full moon's brightness, the maths doesn't check out

This Wikipedia article claims that the brightness of Barnard's star at the distance of 1 AU is roughly the same as that of our Sun at 80 AU, "...comparable to the brightness of the Sun at 80 astronomical units." But, that doesn't remotely check out mathematically! Because, if the visual luminosity of Barnard's star is 0.0004 that of our Sun, as given in this Wikipedia article, then it is obviously at 50 AU distance from the Sun that the 0.0004 level of luminosity is equalled, not 80 AU. Maths: 1/50^2= 0.0004 and so equal!, 1/80^2= ‭0.00015625 and so not equal to 0.0004!‬ The source given for the distance of 80 AU come from the old SolStation.com website and that site was really nothing more than an online magazine so hardly a reliable information source. SolStation.com was also probably quoting some out of date estimate for the calculation for the comparative brightness of Barnard's star, because it hasn't been maintained for about a decade now. Similarly where it says, "Barnard's Star is so faint that if it were at the same distance from Earth as the Sun is, it would appear only 100 times brighter than a full moon...", that is also mathematically wrong. It would actually be nearer 200 times the brightness (177 times to be more precise) of a full moon.