Astronomical Observations & Research |
Abdul Ahad's Catalog of Red Stars - First edition, May 2004
Compiled: circa late 1980s, posted: 5th May 2004 Copyright © 2004 Abdul Ahad. All rights reserved. Stars ranked in descending order of redness (colour index):
Background to my Catalog of Red Stars Since my earliest childhood days of stargazing, noticing the small variations in star colours, both intrinsically from one star to the next, as well as the jewel-like reds, greens and violets produced by atmospheric scintillation, has always been a top feature in my observing. I originally compiled about half of the above list of exceptionally red stars back in the late 1980s from a number of different sources, notably the "Yale Bright Star Catalog" entries listed in the Astronomical Almanac. The criteria for selecting entries in my red stars catalog are:-
Note: Colour indices in excess of +3 quoted in the list above are very "patchy" with no authoritative sources measuring or citing them. In many cases, the actual shade of colour will vary in line with variations in the star's intrinsic brightness. Likewise the indicated magnitude range for both Carbon stars and pulsating red supergiants is highly variable and very approximate. The AA Institute has already commenced preliminary studies on some of these stars in an effort to determine approximate periods, magnitude amplitudes, light curves and other variability characteristics from observations. I hope to be in a position to publish these results at some point in the future, so watch this space (but don't hold your breath)! Abdul Ahad's "Ruby Star"! (CE Tauri / 119 Tauri) The second reddest star in the entire night sky (ranked in terms of its colour index [B-V] in the Johnson UBVRI photometric system) to shine consistently at a naked eye brightness well above the 5th magnitude is the pulsating red supergiant CE Tauri or 119 Tauri. Only Mu Cephei (the "Garnet Star") is slightly redder in that brightness range, as first acknowledged by William Herschel back in the 18th century. I first spotted this star totally inadvertently during a casual binocular sweep back in April 2004, when I instantly took a serious liking to its exceptionally ruby red colour. I then carried out an extensive search of all the online sources and found no prior references to say anyone else had either noted its exceptional gemstone-like colour or made any remarks, comparisons or colour rankings of this relatively *bright* star to Mu Cephei. It never featured in a single red star listing anywhere, and I became the *FIRST* to identify CE Tauri as the *second* reddest star in the entire night sky to shine consistently at a naked eye brightness well above the 5th magnitude. Hence my decision to call this my very own "Ruby Star" as discussed here! Above: The night sky's reddest stars plotted on apparent magnitude vs colour index - click to see a larger image. [Abdul Ahad] [Above image credit: © T. Credner & S. Kohle, AlltheSky.com] "All these countless stars in their myriad of scintillating colours and heavenly sparkle are yours to name and refer to as you wish - except for the one marked by the arrow. Whenever it catches your sight in your celestial wanderings, always refer to this star as Abdul Ahad's "Ruby star" from this day forth . . . And be it universally acknowledged that Abdul Ahad was the first to publicly remark on this star's exceptionally gemstone-like appearance, and claim this star as "his" on Usenet as of 1st May 2004." The Bluest Stars in the Sky By definition, if the reddest stars in the night sky represent the heaven's sparkling garnets and rubies, then the bluest stars - on the opposite end of the spectrum - must represent the night sky's sapphires. The very hot, bluish O-class star Zeta Puppis in the southern skies has one of the highest negative colour indices (B-V) at -0.26 and should look very blue in a telescope. Visible in the northern hemisphere, the 4th magnitude variable star S Monocerotis is amongst the bluest, with a color index of -0.25. The brightest of all the blue stars in the night sky is Spica, with a colour index of -0.23. A good look at Spica through a telescope is a totally 'mesmerising' experience on spring evenings. Astronomical Observations & Research home page Star Colours - The Johnson UBVRI Photometric System Research reference on *my* star (CE Tauri)! Copyright © 2004 Abdul Ahad. All rights reserved. |