"Alpha Centauri" is the mostly-correct answer to the question "What is the nearest star?". Alpha Centauri is actually a three-star system, comprising two sun-like stars in a solar-system-size orbit, and a third dim and distant red-dwarf companion. This third star, Proxima Centauri, is slightly closer to us (4.22 ly) than its two larger siblings. So, after the Alpha-Centauri system, what is the next nearest star? The answer is Barnard's Star in the constellation Ophiuchus. Barnard's Star is a red dwarf just under 6 ly distant and shines at magnitude 9.5, meaning it can't be see without a telescope.
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| The red dot in the center is Barnard's Star, the next nearest star after the Alpha Centauri system. |
The images in tonight's (31 Oct) session were obtained with a Meade 80mm f/5 achromatic (doublet) refractor and an Olympus E-M1iii camera.
Comet C/2025 A6 (Lemmon) was putting on quite a show, but I didn't realize it until I processed the images afterward. The comet was apparently hit by an intense burst of solar wind, which warped and knotted the ion tail. I was watching the comet with a Celestron C5 Schmidt-Cassegrain telescope, but none of this drama was visible to the eye.
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| Comet C/2025 A6 (Lemmon), 7:38 pm MDT. |
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| About to disappear, 29 min later. 8:07 pm MDT. |
Based on a reported distance of 116.8 million km, the change in angular separation of that knot in the tail from the comet's head works out to about 86 km/s relative velocity.
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