Where Is Star Plus?

Bright star in the northeast sky

• QUESTION: Hello from SE Wyoming, My husband has been watching a bright star in the northeastern sky that seems to have several vibrant colors as it twinkles rapidly. I saw your answer from 2007 about Capella. We are 30 miles east of Cheyenne WY in our location. Can you tell us more about Capella? Is is a relatively new star? The brightness of the star's colors is intriguing to say the least. We know little about astronomy but are anxious to learn. Could you also recommend some books for beginners? Thank you. Judy and Jack in WY ANSWER: Hi Judy and Jack, Well, you didn't give me a time of night, (the most critical factor) but I'm going to guess it's around midnight till 1am and it would be the zero magnitude blue-white Vega, in Lyra the harp (Alpha Lyrae)...in the exact NE.? Capella is a yellow colored star and rises at 10 am right now, so it will be a few more months before zero magnitude Capella is rising in your NE sky at first light. All that twinkling and color changes (sintillation) is caused by our atmosphere.? If we had no atmosphere, there would be no sintillation, no rainbows, no haloes, etc. All the stars would be steady pinpoints right down to the horizon, just like on the moon.? Any departure from this norm...is atmospherics interfering with our view of the night sky.Capella is actually 2 big stars too close to split with a regular telescope, but the spectroscope reveals two separate spectrums, thus there are two stars; thus we call Capella a spectroscopic binary star. It's about 45 lightyears distant. It's located up near the zenith (well,just a little west of your zenith) as darkness falls around 8 pm MDT now. Vega will be at your zenith as darkness falls in August, with Capella just rising in the NE. And if your "mystery" bright star is in the early evening, then it's zero magnitude Arcturus rising in the ENE....which is also another yellowish star. For beginners that want some good information, and good basic star charts, an excellent book is Norton's Star Atlas and Reference Handbook 2000.0 for about $30-40. And since star charts are updated every 50 years, that book is good for the next 40 years, as the star charts will not be updated again until 2050. So that cost averages out at about one dollar per year. Plus you can use the internet for researching out the individual stars...just google Vega or Capella and up will come all sorts of information on them. For general knowledge, use www.skyandtelescope.com www.spaceweather.com www.spaceflightnow.com Hope this helps, Clear Skies, Tom Whiting Erie, PA PS..it also helps to find an astronomy club nearby, and join in with them, as they are always open for newcomers. The brighter stars (there's about 20 of them) are like major cities...if you can learn and memorize where New York, Chicago, LA, Miami are, then you can also learn and memorize some 20 stars their location and names, too. FOLLOW UP: A good start for researching Capella is athttp://www.astro.illinois.edu/~jkaler/sow/capella.html Oh, Yes, both Vega and Capella are relatively young, massive stars being only about 400 to 500 million years old (Compared to our sun and Solar System age of nearly 5 billion years). So they are only one-tenth the age of the sun. And their lifespans are very short, being more massive stars, in the range perhaps only several billion years. (The more massive the star, the shorter it's lifespan, as it uses up its hydrogen fuel exponentially faster). ---------- FOLLOW-UP ---------- QUESTION: Just learned something: time of observation is important! Thanks, Tom. The star we saw in the NE was about 9 p.m. Mountain Daylight Saving Time. Thanks again for your time and all the information. Blessings, Judy in WY

• Answer:

  Hi Judy,9 pm local time is Arcturus? (Alpha Bootis) rising in the ENE.Vega (Alpha Lyrae) rises about 2.5 hours later in the NE sky.So that's golden yellow orange Arcturus, at zero magnitude.Arcturus kind of marks the beginning of the summertime sky inthe Eastern sky.? It's always nice to see an "old friend" everylate springtime.A red-giant....star, a star that's already evolved off the MainSequence on the HR diagram, and is now fusing helium nuclei init's core to carbon nuclei (the triple alpha process)Arcturus is also a Population II star, very deficient in the heavymetals (a heavy metal to astronomy is any element heavier thanhydrogen and helium), AND it's in a North-South orbit around theGalaxy, so it doesn't follow the "local flow" of every nearby star orbiting around the Milky way Galaxy in the plane of the Galaxy, it's in a "polar" orbit, probably thrown out of a globularstar cluster many millions of years ago...a rogue in that sense.(There are only 4 of the brightest stars that are zero magnitude...Capella, Vega, Arcturus, and Rigel in Orion.? One star is stillbrighter, Sirius the Dog Star (in the SSW as darkness falls at-1.5 magnitude, and THE brightest real star in our night sky) then all the other 15 bright stars are only 1st magnitude, down to Regulus in Leo at 1.33 magnitude. Dimmer than that are 2nd magnitude...Polaris, most of the Big Dipper stars, etc. Then nextare 3rd magnitude, down to 6th mag the naked eye limit.Binoculars get you down to 9th magnitude objects, a 6 inch diameterscope gets you down to 13th magnitude, and so on.(It's a reverse scale, the lower the number, the brighter the object,and it's exponential as far as brightness difference, but that'sanother story.)? See, there is a system to it.Oh, and all this doesn't count those few other very bright starsthat we can't see up here because they are Southern Hemisphere objects only.Oh, the Alpha usually means...the brightest star in that constellation (area of sky), next is generally Beta, Gamma, and so on down the Greek (lower case) alphabet. That's how the brighter stars are named....believe it or not, there is a systemto all this...all you have to do is learn the system, then it'sa piece of cake.? (But there are a couple of exceptions to thatAlpha is the brightest star....rule. You just have to memorizethe exceptions, that's all.)Clear Skies,Tom PS...and many thanks for the nice rating. FOLLOW UP: I checked it out for you on the www.skyandtelescope.com website; Cheyenne Astronomical Society with 80 members, so they are about the same size as our group in Erie, PA....give them a call at the URL below...http://www.skyandtelescope.com/community/organizations/searchresults?clubType=47956&city=&countrySelect=47501&stateSelect=47941&description=?istration=Find+Club Clear Skies, Tom