HD 188753

Many of us have been hearing or seeing in our everyday lives that our planet Earth has only one sunset. I am telling ‘only’ because their is a planet name HD 188753AB which has 3 sunsets or triple sunsets.

HD 188753 is a triple star system located approximately 149 light-years away from Earth in the constellation of Cygnus, the swam. The system is composed of HD 188753A, a yellow dwarf; HD 188753B, an orange dwarf; and HD 188753C, a red dwarf.

The primary star(HD 188753A) is like our Sun, weighing 1.06 solarmasses.  The other two stars(HD 188753B and HD 188753C) form a tightly bound pair, which is separated from the primary by approximately the Sun-Saturn distance.

The suns' colors(yellow) and sizes reflect their masses, temperatures and distances to the planet. The second star is farther away, less massive and cooler than the first, appearing smaller and yellow. The final star is at the same distance as the second, but it is still less massive and cooler, appearing even smaller and orange-red in color. Our Sun is a bit cooler than the hottest star of the system.

They orbit the primary with a period of about 25.7 years and an orbital eccentricity of about 0.50. The periastron distance of this orbit is 6.2 AU.

A yellow dwarf that completes each orbit in only 3.3 days. The main star is orbited every 25.7 years by two dwarfs revolving around each other (one is orange and another is red). The oribiting dwarfs are locked in a 156 days orbit. And each star sinking into the horizon and bouncing so much light off the planet darkness approaches the moon slowly.

×××××

Thank you reading my blog, meet you in the next blog.