Physics

posted by .

Halley’s comet orbits the Sun with a period of 76.2 years.
a) Find the semi-major axis of the orbit of Halley’s comet in astronomical units (1 AU is equal to the semi-major axis of the Earth’s orbit



Physics - drwls, Thursday, May 5, 2011 at 8:51am
There is a simple form of Kepler's Third law for objects orbiting the sun.

If the period P is in years and the semimajor axis a is in a.u.,

P^2 = a^3

You know that P = 76.2 yr

Solve for a


Thanks a lot, I'm confused with part b as well... could you please help me with this?
If Halley’s comet is 0.56 AU from the Sun at perihelion, what is the maximum distance from the Sun, and what is the eccentricity of its orbit?

  • Physics -

    (perihelion distance) + (aphelion distance) = 2 a

    You should have got a = 17.97 au in the first part

    The aphelion (greatest) distance is therefore 36.95 - 0.56 = 35.4 au

    There is an equation that relates eccentricity to the perihelion/semimajor ratio.The eccentricity (e) equals 1 - (perihelion)/(semi-major axis).

  • Physics -

    e = 1 - (0.56/17.97) = 0.9688

    e = 0 would be a circular orbit
    e = 1 is the maximum possible eccentricity for an ellipse.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. physics

    the period of a comet is 100 years. At ists closest approach(perihelion), it is 0.37 AU from the sun. What is the semi-major axis of the comet's orbit?
  2. AP Physics Halley's Comet

    Halley's comet orbits the sun roughly once every 76 years. It comes very close to the surface of the Sun on its closest approach. Estimate the greatest distance of the comet from the sun. Is it still in the Solar System?
  3. Physics

    Halley’s comet orbits the Sun with a period of 76.2 years. a) Find the semi-major axis of the orbit of Halley’s comet in astronomical units (1 AU is equal to the semi-major axis of the Earth’s orbit).
  4. Physics

    Halley’s comet orbits the Sun with a period of 76.2 years. a) Find the semi-major axis of the orbit of Halley’s comet in astronomical units (1 AU is equal to the semi-major axis of the Earth’s orbit
  5. Physics

    Halley’s comet orbits the Sun with a period of 76.2 years. a) Find the semi-major axis of the orbit of Halley’s comet in astronomical units (1 AU is equal to the semi-major axis of the Earth’s orbit Physics - drwls, Thursday, …
  6. physics

    A comet orbits the Sun with a period of 72.8 yr. (a) Find the semimajor axis of the orbit of the comet in astronomical units (1 AU is equal to the semimajor axis of the Earth's orbit). (b) If the comet is 0.55 AU from the Sun at perihelion, …
  7. Physics

    A comet orbits the Sun with a period of 72.0 yr. (a) Find the semimajor axis of the orbit of the comet in astronomical units (1 AU is equal to the semimajor axis of the Earth's orbit). (b) If the comet is 0.60 AU from the Sun at perihelion, …
  8. physics

    A comet orbits the Sun with a period of 71.8 yr. (a) Find the semimajor axis of the orbit of the comet in astronomical units (1 AU is equal to the semimajor axis of the Earth's orbit). (b) If the comet is 0.50 AU from the Sun at perihelion, …
  9. Physics

    A comet orbits the Sun with a period of 72.0 yr. (a) Find the semimajor axis of the orbit of the comet in astronomical units (1 AU is equal to the semimajor axis of the Earth's orbit). (b) If the comet is 0.60 AU from the Sun at perihelion, …
  10. College Physics

    In 1986, the distance of closest approach of Halley’s comet to the Sun is 0.57AU. (1 AU is the mean Earth-Sun distance = 150 million kilometers.) The comet’s speed at closest approach is 54.97 km/s. (a) – By 1989, Halley’s …

More Similar Questions