Albireo

By Phil Plait | February 14, 2006 9:33 pm


I’m sometimes asked what my favorite object in the sky is. I have lots, actually, but when I’m out with my telescope under the night sky, I have a secret favorite I always take a look at when it’s up. It’s not some distant galaxy or a bright nebula as you might expect. It’s actually just a star.

Well, it’s really two stars, which is one of the reasons I like it. The star’s name is Albireo, and it’s the head of the swan constellation of Cygnus, visible from the northern hemisphere in the summer through early winter. To the unaided eye it looks like one star, but that’s an illusion due to its vast distance of about 400 light years (4000 trillion kilometers). The two stars blur together, like distant car headlights on a highway.

Double stars are generally more interesting to observe than single stars, since it’s relatively rare to be able to see two bright stars through an eyepiece at the same time. You usually see lots of faint stars, so when two are bright and close together, it’s more visually appealing.

But Albireo outshines the rest because of the colors of the two components. Everyone seems to see different hues from them (which is also part of the appeal), but to me the brighter of the two is a warm, soft, orange, and the fainter a sharp, cold, sapphire blue. Others see the brighter star as red, or yellow. It depends on how your eye perceives contrasting colors, as well as the seeing conditions.

But no matter what, they make a lovely pair, a delight to the eye. It’s one of my favorites to show people at observatory public nights. They always gasp when they see it.

Photographically, it’s difficult to capture the stars well because they are so much brighter than their surrounding starfield, and the contrasting colors make it hard to get the color balanced on one star without washing out the other. But astrophotographer Stefan Seip made a glorious image of Albireo (the image at the top of this entry is but a small portion of the much larger image). He has an amazing talent for shooting the stars; his images are fantastic. Check out his website and click around his images. They are truly beautiful.’

CATEGORIZED UNDER: Astronomy, Cool stuff, Science

Comments (36)

  1. Dan Gerhards

    One of my favorites too!

    I found this picture a while ago. It shows the colors of the stars even better: http://yumis.net/space/star/k_image/st-alub2.jpg. The site is in Japanese though, so I can’t read the name of the photographer.

    I once saw Albireo on a personalized license plate. I can’t imagine what non-astronomers try to make that say!

  2. “Albireo”, eh? Sounds like a good name for a firstborn child.

  3. Linda K

    Thank you. Its a beautiful photo.

  4. Evolving Squid

    Cool that this entry came up. On the weekend, someone was asking what kind of cool things they could see with their new telescope and I mentioned Albireo because it’s one of my favourites too. I’ll point them at this blog entry.

  5. Lawson

    How can i find this in the winter sky in india ?

  6. ioresult

    The name of the star came to us all mangled by historic errors. At first, the arabs named the star “al-Minhar al-Dajajah” which means “the neck of the chicken”. The Swan constellation was known as the Chicken by ancient Arab astronomers. During the middle ages, translators misunderstood and translated the name to “of the Iris” (the flower), which is written “ab ireo” in latin. Still later, other translators, thinking that was a misspelling from an arab name, readapted the name as “al-Bireo” and so “Albireo”. And that is not an arab word so it then lost all meaning.

  7. ioresult

    Interesting fact: Albireo is in fact a triple star. The bright orange is in fact a double in itself, composed of a K class orange helium burning giant and a B class blue star. The visible blue is also a B class star.

  8. GordonH

    I share your enjoyment of Albireo. Its usually one of the first objects I look at anytime its up.

    Here in Michigan its nicknamed the U of M star – Maize and Blue!

  9. This was the first object I pointed my telescope at when I got it a few years back. Because of that, it’s always held a special place for me as well. Thanks for the image.

  10. Kaptain K

    Sweet!

    My personal favorite – the one I look for first (whenever it’s up) and the one I show to others is Epsilon Lyrae (the double double). What looks like a single star to the naked eye (slightly “fuzzy” to the sharp eyed) becomes a matched pair of blue-white gems in binoculars, but even in the smallest of scopes, it resolves into FOUR matched stars in two pairs!

  11. Dan G – your link pic was awesome! Thanks.

  12. Jon Niehof

    What, we aren’t going to argue about whether it’s an optical double or a true binary? But that’s always so much fun :)

    (or is there new information in that I haven’t heard?)

  13. Peter Backus

    Here’s another great photo of Albireo.
    http://antwrp.gsfc.nasa.gov/apod/ap050830.html

    The star is visible briefly before dawn this month, rising around 5 AM. It will rise about 2 hours earlier every month and will be visible in the east around 9PM (2100) in June.

  14. I wonder how the view would be standing on a planet orbiting one of these stars?

  15. I just saw Dr. Phil’s “talk in Michigan” and it was absolutely fantastic. Anyone within 100 miles of Adrian to GET OVER HERE for his talk at 7:15pm at the Adrian College Planetarium. Adrian is between Ann Arbor, Toledo, and Jackson, MI. Mapquest the intersection of N. Charles St and Williams St, and you’ll be right there. Zip code is 49221.

  16. Chip

    Beautiful stars. Jim Kahler points out in the Albireo link above, (presumably from a hypothertical planet orbiting Albireo B,) star Albireo A “would appear as brilliant orbiting orange and blue points about half a degree apart, the K giant shining with the light of 35 full Moons, the close class B companion at about half of that.”

    So it’s the A binary star (orange and blue) combined with the more distant orbiting B star that we “see”.

  17. Dan Gerhards Says: “I once saw Albireo on a personalized license plate. I can’t imagine what non-astronomers try to make that say! ”

    Was the plate on a Saab or Volvo? Albiero is sometimes called the “Swedish binary” since blue and yellow are the colors of the Swedish flag.

    – Jack

  18. One of my favorites too!

    I enjoyed ioresults comments on the name, and the addition that it is really a triple. What type of binary is the orange-blue K-B pair?

    I ask my students, almost every Fall “What colors do you see? Make up your mind, and don’t tell anyone until all have taken a look.” Mostly I get yellow and blue-green, but I have heard anything from white-yellow-gold (orange very rarely) & blue, blue-green, aqua, turqoise and even purple or pink!?! Clearly people have wildly different interpretations of color, at low levels.

  19. Hey! no Volvo drivers here please, we’d like to move a bit faster than that here….

  20. Evolving Squid

    How can i find this in the winter sky in india ?

    I picked an arbitrary location of Madras, India and fired up Starry Night.

    At 5 AM, Albireo is around Azimuth 64 degrees, Altitude 19 degrees above the horizon. It rises around 2:30 AM in Madras, so get a pot of coffee going.

  21. Maurizio Morabito

    > the brighter of the two is a warm, soft, orange, and
    > the fainter a sharp, cold, sapphire blue

    isn’t that a case of Bad Astronomy? If the blue one is B and the orange one is K giant, I guess we all know which one is warmer…

  22. P. Edward Murray

    Remember Dr. Hansen?

    He’s on Lou Dobbs in a few minutes!

    Ed Murray

  23. SFwriter

    Mmmmmmmmm! Chicken Madras! Spicy! No, don’t .. think .. about .. it — must think astronomy…

    Yeah, I like Albireo, too. Definitely Orange & Blue to me.

    Hey, Squid! I don’t have Starry Night, and I haven’t unpacked my Astronomy books since I bought this house… Ottawa’s not too far from Hamilton… Have you got numbers for 40 Eridani handy? (In the Star Trek universe, it is supposed to be the one Vulcan circles — heheh). I’ve always wanted to look at it, but never thought of it when I’m set up (Orbiter 9000S reflector). Thanks in advance if you do!

  24. Troy

    As Mr. Spock would say…’fascinating’
    Thanks, very cool also.

  25. P. Edward Murray

    Here it is : 40 (Omicron 2 ) Eridani RA 4h 13m D -07d 44m

    Some interesting links:

    http://www.solstation.com/stars/40erida3.htm

    and a fun one:

    http://www.marketaz.co.uk/StarTrek/Vulcan/Where_is_Vulcan.txt

    Have fun!

  26. P. Edward Murray

    Update from Sky & Telescope on RS Ophiuchi:

    “Update February 15: In the last two days RS Oph has been fading and reddening, losing about 0.4 magnitude per day according to visual reports sent to the AAVSO. As of Wednesday morning (February 15.3 UT), RS Oph was about magnitude 5.7. The star’s low altitude and the full moonlight may or may not be affecting visual estimates and other measurements. Check back here for further developments. “

  27. SFwriter

    Thanks, P. Edward Murray. I found that second link to be, quite literally, “fascinating”, as Troy said earlier.

    Incidentally, you can use the ° or the º (degree) marks by making sure your NUMLOCK is on and then holding the ALT-key while typing (on the numberpad ONLY) 504 for the small degree mark and 167 for the large degree mark. Just thought I’d mention it since we use degrees here so often.

    So if you have a Â¥ to £ away ¾ of the time without impinging on someone’s © I hope this has ® properly with you, even if it takes æons! En français… nah, that wouldn’t make ¢… :-)

    I LOVE being old, and still remembering how to use ASCII

  28. If anyone is interested in observing other color-contrasting doubles, I compiled a list that is available on my website at:

    http://mysite.verizon.net/wayne1026/main/colordouble.html

    I usually feature Albireo at my club’s public star parties since double stars are good at penetrating the bad light polution at our public site. We describe it as the “Cub Scout Star” since many scouts attend our events and they use blue and gold colors.

    Wayne Reed

  29. SFWriter – you learn something new each day ° º – cool

  30. Evolving Squid

    SFWriter:

    Here is the Starry Night output for 40 Eridani, with the viewing location set to Hamilton, ON. I had it select “best viewing time” since 40 Eridani rises just after lunch right now.

    http://img.photobucket.com/albums/v471/dcowan38/board_posts/40eridani.jpg if the picture doesn’t load.

  31. Stuart Greig

    As you say learn something new each day ° ° ° ° ° ° °

    but can you Ø Ã… Æ and ø Ã¥ æ….

    Stuart

  32. MaryLeonard

    I have some favorite ones to…
    You have an excellent site……
    Hey…do you know what happened to
    Tom’s Blog…..???????????????????

    It was he ,who directed me to
    your site……….

    I truely hope you continue with your site……..

  33. Stuart, Æ Ø Ã… and æ ø Ã¥ and I have put them in the right sequence… ;-)

  34. Dori

    Beautiful picture, Uncle Phil. I love Albireo, I’m learning about various stars and constellations in Astronomy this semester, and it’s really interesting. I think this one is my favorite star thus far.

  35. Nice article, Phil.

    And thanks for choosing my image for illustration.

    Stefan

    http://www.astromeeting.de

    My newst images from Chile:
    http://www.astromeeting.de/chile2006.htm

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