Mebsuta — ふたごの二重星

Mebsuta, Epsilon Geminorum, is a luminous yellow supergiant of spectral type G9 Ib lying approximately 840 light-years from Earth in the constellation Gemini. With an estimated radius of 140 times the Sun's and a luminosity around 8,500 times greater, it is one of the intrinsically brightest stars visible in the northern winter sky — it only appears modest (magnitude 2.98) because of its great distance. Its surface temperature is roughly 4,660 K, giving it a warm amber tint at the eyepiece.

Mebsuta sits on the leading (western) foot of the Gemini twins, south of Castor and east of Mu Geminorum. An easy naked-eye star from all but the most light-polluted cities, it is also an excellent binocular target and shares the field of view with several Milky Way clusters, including M35 just two degrees to its northwest. In the telescope Mebsuta shows a delicate pale-yellow hue typical of intermediate-temperature supergiants. Best observed from December through April.

The name comes from the Arabic "mabsūṭah," meaning "the outstretched paw," referring to the mythical paw of a lion that pre-Islamic Arabic astronomy placed here. The Greek name Epsilon Geminorum is a later Bayer designation. Mebsuta was famously occulted by Mars on April 8, 1976, giving astronomers rare timing data on its angular diameter.