119 Tauri – a red supergiant star in the constellation Taurus

119 Tauri is a red supergiant star in the constellation Taurus. It is also known as CE Tauri, is a semiregular variable and its angular diameter has been measured at about 10 mas. Its visual magnitude is 4.38. Because of its moderate brightness, 119 Tauri should be easily visible from locations with dark skies, while it can be barely visible, or not visible at all, from skyes affected by light pollution.

119 Tauri has a spectral class of M2 and a luminosity class of Iab-Ib, intermediate between an intermediate-luminosity supergiant and a less luminous supergiant. It has a diameter that is more than 590 times bigger than that of the Sun’s. This is about 830 million kilometers. It is approximately 1,800 light years from Earth, and with a colour index of +2.07 it is one of the reddest naked eye stars in the night sky. It has a diameter almost the size of Jupiter’s orbit and can be easily seen in the night sky. It is a similar star to Betelgeuse although redder and more distant. It is not part of the Taurus constellation outline but is within the borders of the constellation.

119 Tauri is classified as a semiregular variable star and has been given the variable star designation CE Tauri. The location of the supergiant star in the night sky is determined by the Right Ascension (R.A.) and Declination (Dec.), these are equivalent to the Longitude and Latitude on the Earth. The General Catalogue of Variable Stars gives a magnitude range from +4.23 to +4.54 with a period of 165 days. Other published studies find poorly-defined periodicity, but with possible periods around 270 and 1,300 days.

119 Tauri estimated radius has been calculated as being 1,216.87 times bigger than the Sun. The Sun’s radius is 695,800km, therefore the star’s radius is an estimated 846,697,936.80.km. Its infrared magnitude changes much less than the visual magnitude; the visual brightness changes are driven by changes in temperature which shift the proportion of electromagnetic radiation emitted in the visual range.

119 Tauri is a pulsating star although the pulsation has not been clearly detected in direct angular measurements. Using the 2007 distance, the star is roughly 113,331,408.09 Astronomical Units from the Earth/Sun give or take a few. Observations of TiO lines in its spectrum as its brightness changes show effective temperature changes up to 100 K. An Astronomical Unit is the distance between Earth and the Sun. Calculating its physical properties shows that the bolometric luminosity and radius both change by about 10%, with the radius typically being larger at cooler temperatures. The number of A.U. is the number of times that the star is from the Earth compared to the Sun.

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