APOD: 25 Brightest Stars in the Night Sky (2022 Dec 18)

[APOD Robot]

25 Brightest Stars in the Night Sky

Explanation: Do you know the names of some of the brightest stars? It's likely that you do, even though some bright stars have names so old they date back to near the beginning of written language. Many world cultures have their own names for the brightest stars, and it is culturally and historically important to remember them. In the interest of clear global communication, however, the International Astronomical Union (IAU) has begun to designate standardized star names. Featured here in true color are the 25 brightest stars in the night sky, currently as seen by humans, coupled with their IAU-recognized names. Some star names have interesting meanings, including Sirius ("the scorcher" in Latin), Vega ("falling" in Arabic), and Antares ("rival to Mars" in Greek). You are likely even familiar with the name of at least one star too dim to make this list: Polaris.

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[jb92264@gmail.com]

Are these 25 Stars listed in order of apparent brightness from left to right since they are not listed alphabetically?

[VictorBorun]

Yet to my naked eye if I remember correctly

Antares felt red (in place of pale orange–yellow here)
Arcturus felt very pale yellow (in place of pale orange–yellow here)
Deneb felt white (in place of very pale blue here)
Vega felt very pale blue (in place of white here)

Well, I guess we can explain a red Antares as observer's hypercorrection of bleaching colours when a spec is bright and small.
But for the rest of discrepancies I see no reason

[Ann]

Are these 25 Stars listed in order of apparent brightness from left to right since they are not listed alphabetically?

They are listed in order of brightness.

Ann

[Ann]

Yet to my naked eye if I remember correctly

Antares felt red (in place of pale orange–yellow here)
Arcturus felt very pale yellow (in place of pale orange–yellow here)
Deneb felt white (in place of very pale blue here)
Vega felt very pale blue (in place of white here)

Well, I guess we can explain a red Antares as observer's hypercorrection of bleaching colours when a spec is bright and small.
But for the rest of discrepancies I see no reason

My experience tells me that the color stars look different due to differences in sky color, darkness, moisture etcetera.

I remember the first time ever that I spotted Antares, a southerly star that is hard to see in Sweden. One morning in April, when dawn was on its way, I saw a fantastically orange-red light to the south that just cleared the tree tops of the park across my street. I have never seen Antares look as red as that again. I guess that the dark but yet luminous blue sky created a contrast that enhanced Antares' yellow-orange hue and made it appear redder.

I can also remember seeing Arcturus very low in the sky during dusk. As I watched it through my binoculars, Arcturus shimmered and sparkled like Sirius, except that the colors it displayed were only red and green.

I will never forget the time I observed Arcturus through a telescope, and it looked absolutely lemon yellow.

I will never forget seeing Meissa, Lambda Orionis, through a telescope. Other stars were visible next to it, but Meissa just popped out, because it was so blue.

I think that the best way to judge the color of a star is to observe it again and again, to familiarize yourself with the star's "average" appearance.

Ann

[Ann]

Yet to my naked eye if I remember correctly

Antares felt red (in place of pale orange–yellow here)
Arcturus felt very pale yellow (in place of pale orange–yellow here)
Deneb felt white (in place of very pale blue here)
Vega felt very pale blue (in place of white here)

Well, I guess we can explain a red Antares as observer's hypercorrection of bleaching colours when a spec is bright and small.
But for the rest of discrepancies I see no reason

This is what these stars have looked like to me:

Antares can only be seen in the early mornings in April where I live. It never rises high, and it has always looked quite orange to me. If it rose higher, I would probably not find it as deeply orange, but more yellow-orange or golden.

I have seen Arcturus looking lemon yellow (through a telescope) and like a sparkling light bulb of red and green (through my binoculars at dusk, when Arcturus was very low in the sky). Normally I find it just yellowish, or indeed pale yellow, like you said.

Deneb looks white to me in the sky and bluish through a telescope.

Vega looks very pale blue to me in the sky, but very bluish through a telescope.

Ann

[Ann]

I think the APOD does a relatively good job of bringing out the colors of the stars. I think, however, that Vega looks less blue in the APOD than Canopus or Rigel, and I don't think that is the case in reality. I'm not sure that the photographer has managed to bring out the very subtle color differences of the A- and B-type stars in this sample.

I think the photographer has done a very good job at bringing out the pale hues of Capella, Procyon and Pollux. I think perhaps that Arcturus looks just a tad too red compared with Aldebaran, Betelgeuse and Antares.

Ann

[Ann]

I just looked up Vega at Simbad Astronomical Database, and guess what? Vega's fluxes in ultraviolet, blue and yellow-green light are said to be the same, all of them with an intensity of 0.03. As if Vega's light curve was not a curve, but a line:

Light curve of Vega? I don't think so.

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That's so wrong! Vega's light curve is indeed a curve, and Vega is a lot brighter in blue than in yellow-green light:

Spectrum of Vega. Illustration: David Haworth.

Ann

[Jim Fenner]

Thanks to Tragoolchitr Jittasaiyapan for creating the montage

Worth noting that three of the 25 Brightest Stars are in Crux, the smallest constellation in square degrees.
Before European astronomers carved out Crux from Centaurus, Old Centaurus would have had five of the top 25 brightest stars. Phew!

Also not meaning to boast, but from the latitude of Sydney, all these stars are visible in the course of a year.
Capella, Vega and Deneb do suffer from low altitude

But for total impact, the Orion region takes the cake.

[De58te]

Just for the trivial record, according to Wiki's List of brightest apparent stars, number 26 brightest is Bellatrix in Orion. While Polaris the North Star is 48th brightest.

[orin stepanek]

Just Awesome!

Polaris; two dim to make the list

Dog pondering!

[Cousin Ricky]

Also not meaning to boast, but from the latitude of Sydney, all these stars are visible in the course of a year.
Capella, Vega and Deneb do suffer from low altitude

Same from the Virgin Islands. The 5 stars in Centaurus and Crux are the lowest, with Acrux culminating 9° above my horizon.

[Sa Ji Tario]

In every part of the world, the atmosphere is, due to its pollution, the one that dictates the colors with which we see the stars

[songwriterz]

Nothing to see here. Carry on.

[Cousin Ricky]

I created this simulation, based on the stars’ B – V indices, a few months before the IAU made the names official. I assumed a white point of D65, so the moderately blue stars look less blue than in Mr. Jittasaiyapan’s montage.

Simulation of 17 brightest nighttime stars, plus Garnet Star

Sorry, Ann, I was looking specifically at the Garnet Star, and did not include Mu Columbae or Upsilon Orionis. (I did include them both in a graph I used to calibrate the B – V colors.)

[Chris Peterson]

I just looked up Vega at Simbad Astronomical Database, and guess what? Vega's fluxes in ultraviolet, blue and yellow-green light are said to be the same, all of them with an intensity of 0.03. As if Vega's light curve was not a curve, but a line:

That's so wrong! Vega's light curve is indeed a curve, and Vega is a lot brighter in blue than in yellow-green light:

Be careful with what you're looking at, though. Don't confuse flux with intensity and different energy systems. And watch for how things are normalized. The U, B, and V magnitudes of Vega are all about 0.03. But the fluxes (in one conventional system, measured as erg/s/cm^2/Angstrom) are 4.2e-9, 6.2e-9, and 3.6e-9. So what kind of light curve are you talking about? What Simbad identifies as flux is better described as magnitude.

[johnnydeep]

I vote for "Antares" to be the name of the first human mission to Mars. "Rival to Mars" indeed!

[jkittlejr@gmail.com]

i am confused, what about alpha centuri?

[Chris Peterson]

i am confused, what about alpha centuri?

Rigil Kentaurus is Alpha Centauri!

[johnnydeep]

i am confused, what about alpha centuri?

Rigil Kentaurus is Alpha Centauri!

There's a beautiful image of Alpha Centauri from the Digitized Sky Survey 2 at https://exoplanets.nasa.gov/resources/1 ... roundings/. It's big so here's a smaller version of it:

This wide-field view of the sky around the bright star Alpha Centauri was created from photographic images forming part of the Digitized Sky Survey 2. The star appears so big just because of the scattering of light by the telescope's optics as well as in the photographic emulsion. Alpha Centauri is the closest star system to the Solar System.

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[NateWhilk]

'Sirius ("the scorcher" in Latin)'

Greek, actually. From wikipedia: "Sirius is the brightest star in the night sky. Its name is derived from the Greek word Σείριος, or Seirios, meaning lit. 'glowing' or 'scorching'."

This is the only mistake I've caught in APOD since following it from its early days. But honestly, it's especially unfortunate after this: "Many world cultures have their own names for the brightest stars, and it is culturally and historically important to remember them."

[johnnydeep]

'Sirius ("the scorcher" in Latin)'

Greek, actually. From wikipedia: "Sirius is the brightest star in the night sky. Its name is derived from the Greek word Σείριος, or Seirios, meaning lit. 'glowing' or 'scorching'."

This is the only mistake I've caught in APOD since following it from its early days. But honestly, it's especially unfortunate after this: "Many world cultures have their own names for the brightest stars, and it is culturally and historically important to remember them."

There have been plenty of other mistakes over the years, but that's the human predicament. As for this particular "mistake", I think it's debatable. Ultimately it's from Greek, but it passed through Latin to get to us, with "scorcher" porphing to "the Dog Star" due to the star rising during the "dog days" of summer:

Sirius (n.)
brightest star by magnitude, late 14c., from Latin Sirius "the Dog Star," from Greek Seirios, said to mean literally "scorching" or "the scorcher." But other related Greek words seem to derive from this use, and the name might be a folk-etymologized borrowing from some other language. An Egyptian name for it was Sothis. Beekes suggests it is from PIE root *twei- "to agitate, shake, toss; excite; sparkle" if the original meaning of the star-name is "sparkling, flickering."

The connection of the star with scorching heat is due to its ancient heliacal rising at the summer solstice (see dog days). Related: Sirian (1590s). The constellation Canis Major seems to have grown from the star.

Homer made much of it as [Kyōn], but his Dog doubtless was limited to the star Sirius, as among the ancients generally till, at some unknown date, the constellation was formed as we have it, — indeed till long afterwards, for we find many allusions to the Dog in which we are uncertain whether the constellation or its lucida is referred to. [Richard Hinckley Allen, Canis Major in "Star Names and Their Meanings," London: 1899]

[Ironwood]

Of these brightest stars, I think Deneb is brightest in absolute magnitude. When I was younger it was said to be 1600 light years away. Maybe they have refined that distance these days.

[Ann]

Of these brightest stars, I think Deneb is brightest in absolute magnitude. When I was younger it was said to be 1600 light years away. Maybe they have refined that distance these days.

Unfortunately, Deneb shines too bright in our skies for ESA's Gaia to be able to measure its parallax. If ESA had been able to do that, then we would have known for sure how bright Deneb really is.

In fact, all of the 25 brightest-looking stars are too bright for Gaia to look at them without burning out its instruments (or something).

Ann