Explanation: Beta Cygni is a single bright star to the naked eye. About 420 light-years away it marks the foot of the Northern Cross, famous asterism in the constellation Cygnus. But a view through the eyepiece of a small telescope will transform it into a beautiful double star, a treasure of the night sky in blue and gold. Beta Cygni is also known as Albireo, designated Albireo AB to indicate its two bright component stars. Their visually striking color difference is illustrated in this telescopic snapshot, along with their associated visible spectrum of starlight shown in insets to the right. Albireo A, top inset, shows the spectrum of a K-type giant star, cooler than the Sun and emitting most of its energy at yellow and red wavelengths. Below, Albireo B has the spectrum of a main sequence star much hotter than the Sun, emitting more energy in blue and violet. Albireo A is known to be a binary star, two stars together orbiting a common center of mass, though the two stars are too close together to be seen separately with a small telescope. Well-separated Albireo A and B most likely represent an optical double star and not a physical binary system because the two components have clearly different measured motions through space.
Let's take a better look at the "light curves" of Albireo A and Albireo B:
Spectra of Albireo A and Albireo B. Photo: Robert Eder.
Spectrum of Phi 2 Orionis, spectral class G9. Illustration:
Christophe Pellier.
Note that Albireo A appears to have "three maxima": One in the red part of the spectrum, one in the green part of the spectrum and one, smaller and lower, in the blue part of the spectrum. A spectrum of Phi 2 Orionis, spectral class G9III and therefore a little hotter than Albireo A, shows (more or less) the same "three maxima", although the red one is harder to see.
When I first saw Albireo through a telescope, I was disappointed. Was this star supposed to be so colorful? The yellow component was quite pale, and the blue one was blue, but not amazingly blue by any means.
The B-V index of Albireo A is +1.08. That's just a little yellower than Pollux, +0.99. And the B-V of the blue component is -0.09. I'm impressed. Not.
To make you understand just how pale Albireo A is, compare its spectrum with the spectrum of Betelgeuse! Wowzers!
Spectrum of Betelgeuse, spectral class M2Iab. Illustration: Christophe Pellier.
Ann
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Thu Feb 24, 2022 6:58 am
by Ann
I'm only allowed three attachments per post, so I have to make another post to show you my hands-down favorite colorful triple star. It's 30 and 31 Cygni, along with the small blue star next to 31 Cygni:
30 and 31 Cygni. Photo: Jerry Lodriguss.
Yes, I know. The colors in Jerry Lodriguss' image have been saturated. Nevertheless, yes: The yellow primary, 31 Cygni, is more deeply golden-yellow than Albireo A, with a B-V index of +1.27 versus +1.08 for Albireo. Trust me, there is a difference! And the blue star just below yellow 31 Cygni has a B-V index of -0.13, versus -0.09 for Albireo B. Trust me, there is a difference! And, fantastically, the A2-type star 30 Cygni (to the upper right) has a B-V index of +0.10, and compared with the other two, its color is a pale shade of cyan! Amazing!
In a telescope, Omicron 1 Cygni is a beautiful red, white and blue triple star.
Omicron 1 Cygni is also identified as 31 Cygni. It is a golden-colored K-type red giant that lies at a distance of 881 light-years.
5.6 arcminutes to the northwest of Omicron 1 Cygni lies 30 Cygni, a spectral class A-type star that appears white and is located 615 light-years away.
A third star, HD 192579, lies 107 arcseconds to the south of Omicron 1. This star is a 7th magnitude B-type star with a distinctly blue color that is located 1359 light-years away.
I don't agree with Jerry Lodriguss that 30 Cygni looks white, but apart from that, I wholeheartedly agree with him, and I thank him for bringing out the color contrasts between these three stars so splendidly!
Ann
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Thu Feb 24, 2022 8:50 am
by JohnD
So these two stars (and A is said to be a binary itself) just happen to be in line-of-sight from us? How far apart are they? Would any planets they had be affected if they are close?
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Thu Feb 24, 2022 10:20 am
by Ann
JohnD wrote: ↑Thu Feb 24, 2022 8:50 am
So these two stars (and A is said to be a binary itself) just happen to be in line-of-sight from us? How far apart are they? Would any planets they had be affected if they are close?
I can't do the math at all, but I can offer a few thoughts and figures.
The parallax of Albireo A is about 7 milliarcseconds, and the parallax of Albireo B is about 8 milliarcseconds. This is similar enough, given the uncertainties, that the two stars are at more or less the same distance from us.
The parallax of Albireo B corresponds to a distance of about 400 light-years. The distance to Albireo A would be a little greater, but it is hard to say how much.
The proper motion of Albireo B is faster than the proper motion of Albireo A, some 7 and 6 milliarcseconds per year in right ascension and declination, versus about 1 mas/year in RA and declination for Albireo B. For all of that, Albireo A and B are moving in the same direction in both RA and declination (to the southwest).
When I used my software to try to judge how far apart Albireo A and B are seen to be in two dimensions, I could see that they are much closer together than, say, Alcyone in Pleiades and the little triangle of stars located next to "her". Note that the Pleiades is at a reasonably similar distance from us as Albireo A and B, although the Pleiades is a little farther away.
The size in light-years of the bright core of the Pleiades (which ought to be the familiar mini dipper shape) is supposed to be 8 light-years. I'll leave it to others to figure out how far from Alcyone the little triangle of stars is located.
As I said, the distance between Albireo A and B may be less than that.
Ann
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Thu Feb 24, 2022 1:16 pm
by orin stepanek
I love the beauty of this pair!
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Thu Feb 24, 2022 1:41 pm
by JohnD
Thank you, Ann!
Close, but not that close? Probably any planets in a Goldilocks orbit would only notice a very bright star? Disturbance of their Oort Cloud, if any?
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Thu Feb 24, 2022 2:16 pm
by orin stepanek
JohnD wrote: ↑Thu Feb 24, 2022 1:41 pm
Thank you, Ann!
Close, but not that close? Probably any planets in a Goldilocks orbit would only notice a very bright star? Disturbance of their Oort Cloud, if any?
I'm curious; Do you suppose other stellar systems have Oort Clouds? I have an inkling they probably do! I wonder if the James Webb
Space Telescope will tell us?
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Thu Feb 24, 2022 3:46 pm
by Chris Peterson
Ann wrote: ↑Thu Feb 24, 2022 6:37 am
Let's take a better look at the "light curves" of Albireo A and Albireo B:
APOD February 24 2022 Albireo Robert Eder annotated.png
Spectra of Albireo A and Albireo B. Photo: Robert Eder.
Phi 2 Orionis G9 spectrum Christophe Pellier.png
Spectrum of Phi " Orionis, spectral class G9. Illustration:
Christophe Pellier.
Note that Albireo A appears to have "three maxima": One in the red part of the spectrum, one in the green part of the spectrum and one, smaller and lower, in the blue part of the spectrum. A spectrum of Phi 2 Orionis, spectral class G9III and therefore a little hotter than Albireo A, shows (more or less) the same "three maxima", although the red one is harder to see.
When I first saw Albireo through a telescope, I was disappointed. Was this star supposed to be so colorful? The yellow component was quite pale, and the blue one was blue, but not amazingly blue by any means.
The B-V index of Albireo A is +1.08. That's just a little yellower than Pollux, +0.99. And the B-V of the blue component is -0.09. I'm impressed. Not.
To make you understand just how pale Albireo A is, compare its spectrum with the spectrum of Betelgeuse! Wowzers!
Spectrum of Betelgeuse Christophe Pellier.png
Spectrum of Betelgeuse, spectral class M2Iab. Illustration: Christophe Pellier.
Ann
I'm not sure what you mean by "paler". All the spectra demonstrate is that Betelgeuse is cooler, and therefore redder.
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Thu Feb 24, 2022 3:55 pm
by Chris Peterson
JohnD wrote: ↑Thu Feb 24, 2022 8:50 am
So these two stars (and A is said to be a binary itself) just happen to be in line-of-sight from us? How far apart are they? Would any planets they had be affected if they are close?
It's uncertain (in fact, it's uncertain that they aren't actually a true binary... just that the evidence points away from that conclusion) since the uncertainty in the distance measurements results in their measured distances overlapping. Coincidental line-of-sight binaries are pretty rare compared with true binaries.
In any case, if these stars were close enough together for planetary systems to be impacted they would almost certainly be members of the same system, and with an orbital period short enough for us to detect. Which we don't.
Ann wrote: ↑Thu Feb 24, 2022 6:37 am
Let's take a better look at the "light curves" of Albireo A and Albireo B:
APOD February 24 2022 Albireo Robert Eder annotated.png
Spectra of Albireo A and Albireo B. Photo: Robert Eder.
Phi 2 Orionis G9 spectrum Christophe Pellier.png
Spectrum of Phi " Orionis, spectral class G9. Illustration:
Christophe Pellier.
Note that Albireo A appears to have "three maxima": One in the red part of the spectrum, one in the green part of the spectrum and one, smaller and lower, in the blue part of the spectrum. A spectrum of Phi 2 Orionis, spectral class G9III and therefore a little hotter than Albireo A, shows (more or less) the same "three maxima", although the red one is harder to see.
When I first saw Albireo through a telescope, I was disappointed. Was this star supposed to be so colorful? The yellow component was quite pale, and the blue one was blue, but not amazingly blue by any means.
The B-V index of Albireo A is +1.08. That's just a little yellower than Pollux, +0.99. And the B-V of the blue component is -0.09. I'm impressed. Not.
To make you understand just how pale Albireo A is, compare its spectrum with the spectrum of Betelgeuse! Wowzers!
Spectrum of Betelgeuse Christophe Pellier.png
Spectrum of Betelgeuse, spectral class M2Iab. Illustration: Christophe Pellier.
Ann
I'm not sure what you mean by "paler". All the spectra demonstrate is that Betelgeuse is cooler, and therefore redder.
Paler? A more washed-out yellow color, not at all deeply orange! That's what I meant.
Ann wrote: ↑Thu Feb 24, 2022 6:37 am
Let's take a better look at the "light curves" of Albireo A and Albireo B:
APOD February 24 2022 Albireo Robert Eder annotated.png
Spectra of Albireo A and Albireo B. Photo: Robert Eder.
Phi 2 Orionis G9 spectrum Christophe Pellier.png
Spectrum of Phi " Orionis, spectral class G9. Illustration:
Christophe Pellier.
Note that Albireo A appears to have "three maxima": One in the red part of the spectrum, one in the green part of the spectrum and one, smaller and lower, in the blue part of the spectrum. A spectrum of Phi 2 Orionis, spectral class G9III and therefore a little hotter than Albireo A, shows (more or less) the same "three maxima", although the red one is harder to see.
When I first saw Albireo through a telescope, I was disappointed. Was this star supposed to be so colorful? The yellow component was quite pale, and the blue one was blue, but not amazingly blue by any means.
The B-V index of Albireo A is +1.08. That's just a little yellower than Pollux, +0.99. And the B-V of the blue component is -0.09. I'm impressed. Not.
To make you understand just how pale Albireo A is, compare its spectrum with the spectrum of Betelgeuse! Wowzers!
Spectrum of Betelgeuse Christophe Pellier.png
Spectrum of Betelgeuse, spectral class M2Iab. Illustration: Christophe Pellier.
Ann
I'm not sure what you mean by "paler". All the spectra demonstrate is that Betelgeuse is cooler, and therefore redder.
Paler? A more washed-out yellow color, not at all deeply orange! That's what I meant.
JohnD wrote: ↑Thu Feb 24, 2022 8:50 am
So these two stars (and A is said to be a binary itself) just happen to be in line-of-sight from us? How far apart are they? Would any planets they had be affected if they are close?
It's uncertain (in fact, it's uncertain that they aren't actually a true binary... just that the evidence points away from that conclusion) since the uncertainty in the distance measurements results in their measured distances overlapping. Coincidental line-of-sight binaries are pretty rare compared with true binaries.
In any case, if these stars were close enough together for planetary systems to be impacted they would almost certainly be members of the same system, and with an orbital period short enough for us to detect. Which we don't.
Have we looked that closely to see if we can find any planets in orbit around either Albireo? Remember that Albireo A is a giant, and its evolution into gianthood might have disturbed its planets, might it not?
And surely we don't look that closely for planets in orbit around hot stars like Albireo B, which will die too soon for life to evolve into interesting life forms on any of its planets?
JohnD wrote: ↑Thu Feb 24, 2022 8:50 am
So these two stars (and A is said to be a binary itself) just happen to be in line-of-sight from us? How far apart are they? Would any planets they had be affected if they are close?
It's uncertain (in fact, it's uncertain that they aren't actually a true binary... just that the evidence points away from that conclusion) since the uncertainty in the distance measurements results in their measured distances overlapping. Coincidental line-of-sight binaries are pretty rare compared with true binaries.
In any case, if these stars were close enough together for planetary systems to be impacted they would almost certainly be members of the same system, and with an orbital period short enough for us to detect. Which we don't.
Have we looked that closely to see if we can find any planets in orbit around either Albireo? Remember that Albireo A is a giant, and its evolution into gianthood might have disturbed its planets, might it not?
And surely we don't look that closely for planets in orbit around hot stars like Albireo B, which will die too soon for life to evolve into interesting life forms on any of its planets?
Ann
You misunderstand me, I think. If they were close enough together to affect any planetary systems, they would be in a close enough orbit around each other that we would detect it. As the minimum orbital period we get from our measurements is around 100,000 years, the stars must be too far apart to have much effect on each other. The question isn't about the likelihood of planetary systems, it's about whether the stars are close enough together for any planetary systems that might exist to be perturbed.
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Fri Feb 25, 2022 4:43 am
by Ann
Chris Peterson wrote: ↑Thu Feb 24, 2022 3:46 pm
I'm not sure what you mean by "paler". All the spectra demonstrate is that Betelgeuse is cooler, and therefore redder.
Well, that was my point. Albireo A is nowhere near as cool as Betelgeuse, and nowhere near as deeply yellow-orange.
Of course, the yellow hue of Albireo A may be slightly diluted by the K-type giant's Vega-like close-in (and to human observers, invisible) companion.
Ann
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Fri Feb 25, 2022 9:07 am
by JohnD
Thanks to all for the points discussed above. We are often told that space is so big (Its further to the next star than the post office down the road!) so that even when galaxies collide, stars would not. But surely in that vastness, and enormous numbers of stars, a few must at least come close. Was this an example?
Earth is afraid of another 'dinosaur-killer', impacting asteroid, and is thinking of ways to identify and divert such a monster. Even a glancing pass by another star would be far beyond any conceivable defence, and a much longer story, but what a story!
John
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Fri Feb 25, 2022 11:05 am
by Ann
JohnD wrote: ↑Fri Feb 25, 2022 9:07 am
Thanks to all for the points discussed above. We are often told that space is so big (Its further to the next star than the post office down the road!) so that even when galaxies collide, stars would not. But surely in that vastness, and enormous numbers of stars, a few must at least come close. Was this an example?
Yes, maybe Albireo is an example, although the stars don't seem to have come close enough to really affect one another.
But there is a word for stars that come so close that they interact, and that is blue straggler. They are typically found in the crowded centers of globular clusters, and they stand out because they are relatively massive and remain on the main sequence (that is, they fuse hydrogen to helium in their cores), while almost all other stars of the same mass in a globular cluster have run out of hydrogen in their cores and turned into giants.
Take a look at the color magnitude diagram of globular cluster M55 above. M55 is an old cluster, probably 12 billion years old, and only light-weight stars remain on the main sequence. (Stars on the main sequence fuse hydrogen to helium in their cores.)
Stars continually use up hydrogen and convert it to helium during their main sequence lifetimes. When they have used up the hydrogen in their cores, so that they can no longer sustain themselves by core hydrogen fusion, they become giants and sustain themselves by other means (until they have used up absolutely all fuel available to them, after which they become white dwarfs (or in rare cases neutron stars, or in extreme cases black holes).
Take a look at the diagram again. You can see the red giant branch and the horizontal giant branch. (There is also an asymtotic giant branch, the AGB branch, which is parallel to the red giant branch, but we don't have to worry about that here.) The stars on the red giant branch, the horizontal giant branch and the AGB branch are giants that have used up the hydrogen in their cores.
Yes, but now take a look at the blue straggler "branch". (It is not well-populated, so it is not called a branch.) The stars here are "too massive" and "too blue", and they fuse hydrogen to helium in their cores. Why do the blue stragglers still have hydrogen in their cores, while almost all other stars of the same mass in the globular cluster have not?
This may be how a blue straggler forms. The image shows binary star Algol. The two components were probably always very close together. As the more massive component turned into a red giant, its outer layers became very tenuous and distended. Those outer layers were caught by the gravitational field of the other component, which was still a main sequence star and much more compact. The main sequence star started siphoning off gas from its swollen companion, and that process still goes on. In this way, the now-blue component gained extra mass, while the red component lost mass.
In short, a blue straggler is a star that has received another helping of hydrogen so that it gets more massive and brighter and bluer and can keep on fusing hydrogen to helium in its core while other stars of the same mass have depleted the hydrogen in their cores, and the blue straggler has received that hydrogen from another star!
And other stars can pass sufficiently close to our solar system to cause some disturbances, even if the stars themselves are nowhere near enough to interact in any way:
Every 50,000 years or so, a nomadic star passes near our solar system. Most brush by without incident. But, every once in a while, one comes so close that it gains a prominent place in Earth’s night sky, as well as knocks distant comets loose from their orbits.
The most famous of these stellar interlopers is called Scholz’s Star. This small binary star system was discovered in 2013. Its orbital path indicated that, about 70,000 years ago, it passed through the Oort Cloud, the extended sphere of icy bodies that surrounds the fringes of our solar system. Some astronomers even think Scholz’s Star could have sent some of these objects tumbling into the inner solar system when it passed.
So things happen in space!
Ann
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Fri Feb 25, 2022 1:54 pm
by Chris Peterson
JohnD wrote: ↑Fri Feb 25, 2022 9:07 am
Thanks to all for the points discussed above. We are often told that space is so big (Its further to the next star than the post office down the road!) so that even when galaxies collide, stars would not. But surely in that vastness, and enormous numbers of stars, a few must at least come close. Was this an example?
Earth is afraid of another 'dinosaur-killer', impacting asteroid, and is thinking of ways to identify and divert such a monster. Even a glancing pass by another star would be far beyond any conceivable defence, and a much longer story, but what a story!
John
Their proper motions are not sufficiently different to completely rule out being a binary system. So they may have formed together, or they may just be passing nearby each other. Either way, they are far apart. Of course, stars come close to others all the time. What is extremely rare is for them to come close enough that they touch... that is, to actually collide.
<<The national flag of Ukraine has two equally sized horizontal bands of blue and yellow (Constitution of Ukraine, Article 20). The combination of blue and yellow as a symbol of Ukrainian lands comes from the flag of the Kingdom of Galicia–Volhynia used in the 12th century. As a national flag, the blue and yellow bicolour has been officially used since the 1848 Spring of Nations, when it was hoisted over the Lviv Rathaus. It was officially adopted as a state flag for the first time in 1918 by the short-lived West Ukrainian People's Republic and subsequently used by the Ukrainian People's Republic. When Ukraine was part of the Soviet Union, the flag was outlawed and, before 1949, there was no official state flag until the adoption of the red-azure flag of the Ukrainian SSR. The blue and yellow flag was provisionally adopted for official ceremonies in September 1991 following Ukrainian independence, before finally officially being restored on 28 January 1992 by the parliament of Ukraine.
The roots of Ukrainian national symbols come from pre-Christian times when yellow and blue prevailed in traditional ceremonies, reflecting fire and water. The most solid proof of yellow and blue colours could be traced as far as the Battle of Grunwald, in which militia formations from various lands of the Polish–Lithuanian Commonwealth participated.
Yellow–blue, red-black, crimson-olive and especially raspberry colour banners were widely used by Cossacks between the 16th and 18th centuries. These were not the only possible combinations, since normally Cossacks would fly their hetman's banners, which were similar to the coats of arms of the nobility. Also, yellow and blue were the colours common on coats of arms in Galicia. In fact, the coat of arms of Lviv to this day remains a golden lion on a blue field.
Some put the starting point of the adoption of the current national flag of Ukraine to 1848 when, during the Spring of the Nations on 22 April 1848, a yellow and blue banner was adopted by the Supreme Ruthenian Council in Lemberg (Lviv), the capital of the Kingdom of Galicia and Lodomeria, and flew over the city's magistrate for the first time. Although this move did not have significant consequences, the newly formed Ukrainian divisions in the Austrian army used yellow and blue banners in their insignia.>>
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Sat Feb 26, 2022 9:33 am
by JohnD
One of the widest thread diversions ever, neufer, but weirdly appropriate when we are discussing Blue and Gold, and with every reason today for letting the flag of Ukraine fly in as many places as possible.
Albireo is an ancient name, a mixture of Greek, Arabic and Latin according to the Wiki. Beta Cygni is its Bayer designation. In view of it's colours, is it possible to ask the IAU to add "Ukraine" to its name?
John
<<The national flag of Ukraine has two equally sized horizontal bands of blue and yellow (Constitution of Ukraine, Article 20). The combination of blue and yellow as a symbol of Ukrainian lands comes from the flag of the Kingdom of Galicia–Volhynia used in the 12th century. As a national flag, the blue and yellow bicolour has been officially used since the 1848 Spring of Nations, when it was hoisted over the Lviv Rathaus. It was officially adopted as a state flag for the first time in 1918 by the short-lived West Ukrainian People's Republic and subsequently used by the Ukrainian People's Republic. When Ukraine was part of the Soviet Union, the flag was outlawed and, before 1949, there was no official state flag until the adoption of the red-azure flag of the Ukrainian SSR. The blue and yellow flag was provisionally adopted for official ceremonies in September 1991 following Ukrainian independence, before finally officially being restored on 28 January 1992 by the parliament of Ukraine.
The roots of Ukrainian national symbols come from pre-Christian times when yellow and blue prevailed in traditional ceremonies, reflecting fire and water. The most solid proof of yellow and blue colours could be traced as far as the Battle of Grunwald, in which militia formations from various lands of the Polish–Lithuanian Commonwealth participated.
Yellow–blue, red-black, crimson-olive and especially raspberry colour banners were widely used by Cossacks between the 16th and 18th centuries. These were not the only possible combinations, since normally Cossacks would fly their hetman's banners, which were similar to the coats of arms of the nobility. Also, yellow and blue were the colours common on coats of arms in Galicia. In fact, the coat of arms of Lviv to this day remains a golden lion on a blue field.
Some put the starting point of the adoption of the current national flag of Ukraine to 1848 when, during the Spring of the Nations on 22 April 1848, a yellow and blue banner was adopted by the Supreme Ruthenian Council in Lemberg (Lviv), the capital of the Kingdom of Galicia and Lodomeria, and flew over the city's magistrate for the first time. Although this move did not have significant consequences, the newly formed Ukrainian divisions in the Austrian army used yellow and blue banners in their insignia.>>
I, too, stand with Ukraine, so let my offer the Bridge of Öresund, the bridge that links Malmö and Copenhagen, in the colors of the Ukrainian flag.
And then I have to show you this...
Click to play embedded YouTube video.
Beta Cygni (Albireo-???) as seen in a video by Dr Becky!!!
Had to show you Albireo as it looks in a video by Dr. Becky! In the picture at right you can see what Albireo (Beta Cygni!!) looks like at 9.45 into Dr. Becky's video. Check it out for yourself! The blue component has grown mighty bright, hasn't it?
Ann
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Sat Feb 26, 2022 11:48 pm
by JohnD
Is the blue star in front of the Gold, from us, then?
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Sun Feb 27, 2022 3:43 am
by alter-ego
JohnD wrote: ↑Sat Feb 26, 2022 11:48 pm
Is the blue star in front of the Gold, from us, then?
If I interpret your question correctly, then the answer is no.
Albireo A (gold star) has the larger parallax so it's closer to us (i.e., the gold star in front of the blue star from us)
Re: APOD: Beautiful Albireo AB (2022 Feb 24)
Posted: Sun Feb 27, 2022 9:09 am
by JohnD
OK, my education progresses, but how has the blue overcome the gold, then?
Beautiful Albireo AB
