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The Sun follows the solar circle (eccentricity e < 0.1) at a speed of about 255 km/s in a clockwise direction when viewed from the galactic north pole at a radius of ≈ 8.34 kpc [4] about the center of the galaxy near Sgr A*, and has only a slight motion, towards the solar apex, relative to the LSR. [5] [6]
Solar radius is a unit of distance used to express the size of stars in astronomy relative to the Sun.The solar radius is usually defined as the radius to the layer in the Sun's photosphere where the optical depth equals 2/3: [1]
The speed of light in vacuum, commonly denoted c, is a universal physical constant that is exactly equal to 299,792,458 metres per second (approximately 300,000 kilometres per second; 186,000 miles per second; 671 million miles per hour).
Figure 1: Geometry of the Oort constants derivation, with a field star close to the Sun in the midplane of the Galaxy. Consider a star in the midplane of the Galactic disk with Galactic longitude at a distance from the Sun. Assume that both the star and the Sun have circular orbits around the center of the Galaxy at radii of and from the Galactic Center and rotational velocities of and ...
This motion is caused by the movement of the stars relative to the Sun and Solar System. The Sun travels in a nearly circular orbit (the solar circle ) about the center of the galaxy at a speed of about 220 km/s at a radius of 8,000 parsecs (26,000 ly) from Sagittarius A* [ 5 ] [ 6 ] which can be taken as the rate of rotation of the Milky Way ...
In galactic astronomy, peculiar motion refers to the motion of an object (usually a star) relative to a Galactic rest frame. Local objects are commonly examined as to their vectors of position angle and radial velocity. These can be combined through vector addition to state the object's motion relative to the Sun.
Average orbital speed of planet Earth around the Sun: 29 783: 97 713: 107 218: 66 623: The fastest recorded speed of the Helios probes: 70,220: 230,381: 252,792: 157,078: Recognized as the fastest speed achieved by a man-made spacecraft, achieved in solar orbit. Orbital speed of the Sun relative to the center of the galaxy: 251 000: 823 000: ...
This is because the distance between Earth and the Sun is not fixed (it varies between 0.983 289 8912 and 1.016 710 3335 au) and, when Earth is closer to the Sun , the Sun's gravitational field is stronger and Earth is moving faster along its orbital path. As the metre is defined in terms of the second and the speed of light is constant for all ...