Magnitudes And Distances Of Some Of The Stars
Description
This section is from the book "Scientific American Reference Book. A Manual for the Office, Household and Shop", by Albert A. Hopkins, A. Russell Bond. Also available from Amazon: Scientific American Reference Book.
Magnitudes And Distances Of Some Of The Stars
Polaris (alpha ursAE minoris), the north Star
The parallax is 0".075 + 0".015, according to Pritchard (1888). This parallax represents 2,318,000 times the distance of the Earth from the Sun, or, in other words, Polaris is distant 210,000,000,000,000 of miles. Estimating the velocity of light as 187,500 miles per second, the light from Polaris would take thirty-six years to reach the Earth. An express train traveling a mile a minute would have to run without stopping for 479,000,000 years in order to traverse this distance.
Arcturus
The parallax, as determined by Elkin in 1888, is 0".018±0".022, and by Peters, in 1842-43, as 0".127±0".073. The average 0".094 would make the distance of Arcturus from us to be 2,194,100 times the distance from the Earth to the Sun, or 200,000,000,000.-000 of miles; and taking the velocity of light as 187,500 miles, it would require thirty-four years and six months for the light to reach us.
Vega
This was the polar star of our Earth 14,000 years ago, and will again be the polar star in about 12,000 years. The parallax of Vega, which is 0".15, represents 1,375,000 times the distance of the Earth from the Sun, or 12,000,-000,000.000 of miles. It takes twenty years and eight months for the light from Vega to reach us. estimating the velocity of light as 187,500 miles a second.
Altair
The parallax, according to Elkin (1887), is 0".199±0".047. Taking the average between the parallax of Struve, 0".181±0".094, and that of Elkin as 0".19, the distance would be 1,086,000 times the distance of the Earth from the Sun, or 100,000,000,000,000 miles. It would require a little over seventeen years for the light of this star to reach us.
Sirius, The Dog Star
The parallax is 0".266±0".047, according to Elkin (1888). Taking the average parallax of several observers as 0".33, it would represent 625,000 times the distance of the Earth from the Sun, or 58,000,000,000,000 of miles. The light of this star would require nine years and ten months to reach us. It is supposed the diameter of Sirius is about twenty times that of the Sun, and the volume of Sirius is possibly 7,000 times greater than our Sun.
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