Home (Perihelion)

 Astronomy 

Home  
 
 
Home » Astronomy » Perihelion


 

Perihelion

Astronomy  Perigee  Perihelion distance

Perihelion
A planet in an elliptical orbit around the Sun is closest to the Sun at perihelion.


Perihelion
Related Category: Astronomy: General
(pr´´h´ln), point nearest the sun in the orbit of a body about the sun. See apsis.

Perihelion!
Does the Sun look a little brighter to you? Maybe that's because at nine minutes after midnight (UT) tonight, January 2/3, the Earth will be at perihelion, the closest point on its elliptical orbit to the Sun.

perihelion at HighBeam Research
perihelion on Wikipedia
Loading...
Pictures from Google Image Search ...

Definition: perihelion: The orbital point of closest approach to the Sun.
Space Tragedies9 Planets in Nine DaysAstronomy 101
Related Articles ...

At perihelion, Earth's distance from the Sun is r=a(1-e) and at aphelion, it's r=a(1+e).
G=6.673*10-11 N m^2/kg^2
M=1.989*1030 kg ...

Aphelion - the point in an orbit that is farthest from the sun.
Perihelion - the point in an orbit that is closest to the sun.
Sun - the star in our Solar System.
Planet - a large celestial body that orbits a star.

perihelion The closest approach to the Sun of any object in orbit about it.
period The time needed for an orbiting body to complete one revolution about another body.

Perihelion Distance
The distance between the orbiting body and the sun at it's closest approach.

perihelion -- the point in the orbit of the Earth that is closest to the Sun. Currently the Earth reaches perihelion in early January.
prominence -- a large-scale gaseous formation above the surface of the Sun.

Perihelion
All of the planets in our Solar System move around the Sun in elliptical orbits. An ellipse is a shape that can be thought of as a "stretched out" circle or an oval as in the diagram below.

Perihelion
The point in the orbit of an object orbiting the Sun where it is closest to the Sun's center of mass. Earth's perihelion occurs early in January.
Period ...

Perihelion
The point in an object's orbit when it is closest to the Sun (Helios = Sun). Earth is at perihelion each year on about Jan. 3.

Perihelion- a planet or comet's closest approach to the sun
Periodic time- (see sidereal period)
Perturb- to cause a planet or satellite to deviate from a theoretically regular orbital motion ...

Perihelion The position in a heliocentric orbit at which the orbiting object is at its least distance from the Sun.
Phase The percentage illumination, from the observer's perspective, of an object (normally planet or Moon).

perihelion
The point in its orbit where a planet is nearest the Sun.
period-luminosity relation
A relationship between the period and average density of a pulsating star.

perihelion
The point in its orbit where a planet is at its closest to the Sun. Opposite of aphelion.
period-luminosity relationship
The predictable relation between the pulsation period and changes in luminosity of a Cepheid variable star.

Perihelion
the point in the orbit of a planet or other body where it is closest to the Sun.
Perturb
to cause a planet or satellite to deviate from a theoretically regular orbital motion.

Perihelion: Point in the elliptical orbit of a comet about the Sun in which it passes closest to the Sun.

perihelion: The orbital point of closest approach to the sun.
period-luminosity relation: The relation between period of pulsation and intrinsic brightness among Cepheid variable stars.


PERIHELION
The perihelion is a planet or comet's closest approach to the Sun. The Earth is at perihelion (the Earth is closest to the Sun) in January.
...

Perihelion:
The point on an orbit nearest the sun.
Planet:
Large spherical object shining by a star. Our planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto (+Charon ?) ...

Perihelion distance: 0.587 AU
Orbital eccentricity: 0.967
Orbital inclination: 162.24
Orbital period: 76.0 years
Next perihelion: 2061
Diameter: 16 x 8 x 8 km ...

Perihelion and Aphelion are the planet's closest and furthest distances from the Sun, measured in Astronomical Units (AU). 1 AU is defined by the average distance from the Earth to the Sun.
The globes of the planets ...

Perihelion
When the orbit of a planet takes it to the point closest to the Sun.
Planet ...

Perihelion
When an object which revolves around the Sun is at the closest point it gets to the Sun.
Perturbations ...

perihelion -- The point in the path of a planet, asteroid, comet, or other body that is closest to the sun.
Proteus -- In Greek mythology, the son of Poseidon. Personification of the shifting winds and moods of the sea.

perihelion - (n.)
The near point to the sun of the orbit of a body orbiting the sun.
periodic table - (n.) ...

perihelion
That point on the orbit of a Sun-orbiting body nearest to the Sun. Compare aphelion.
persistence ...

At perihelion, when the Earth is closest to the sun, the Earth has a greater angular speed (by Kepler's second law), so the sun has a greater angular speed relative to the Earth.

After perihelion, Comet ISON will fade rapidly, and will keep brighter than magnitude +2 or +3 for just a few days. This is about as bright as the stars in Orion's belt.

2.74 at perihelion
*This table is mainly from the 1965 edition of the Dictionary of Technical Terms for Aerospace Use (NASA SP-7).
Links ...

Aphelion / Perihelion is an object's orbital point (in distance and time) around a star where the object's distance (on its elliptical orbit) from its parent star is farthest / closest.

At present, perihelion occurs during the Southern Hemisphere's summer, and aphelion is reached during the southern winter.

perihelion That point in a solar orbit which is nearest the sun. That orbital point farthest from the sun is called aphelion. The term perihelion should not be confused with parhelion, a form of halo. period 1.

perigee perihelion point in the path of a body orbiting the Sun where it is closest to the Sun.

Another effect to consider is that the Earth's orbit is elliptical so when the Earth is at its closest point to the Sun (at perihelion), it moves quickest. When at its farthest point from the Sun (at aphelion), the Earth moves slowest.

That is an ellipse with perihelion P (point closest to the Sun) at the orbit of Earth and aphelion A (point most distant from the Sun) at the orbit of Mars (drawing). A similar transfer ellipse, between low Earth orbit (say, r = 1.1 RE = 1.

2616 light years penumbra the incomplete part of a shadow surrounding the umbra perigee the innermost point of a terrestrial orbit perihelion the innermost point of a solar orbit phase the fracton of the illuminated part of the Moon ...

(opposite of perihelion) arcuate having the form of a bow; curved; arc-shaped Arago, Dominique François Jean 1786 - 1853 French astronomer and physicist and Director of the Paris Observatory, ...

0 au, and perihelion distances qSee also: Asteroid, Aten asteroids, Perihelion distance, Semimajor axis Asteroid One of a number of objects ranging in size from sub-km to about 1000 km, most of which lie between the orbits of Mars and Jupiter; ...

This is because approximately four days prior to perihelion, Mercury's angular orbital velocity exactly equals its angular rotational velocity so that the Sun's apparent motion ceases; at perihelion, ...

Aphelion is when it is furthest from the Sun and perihelion is when it is closest to the Sun. The distance between the Earth and the Sun is always changing. If that is the case, how can you answer a question like "How far is the Sun from the Earth"?

Mean distance from Sun 149,598,500 km (8.3 lt-min): perihelion distance (early January) 147,100,000 km; aphelion distance 152,100,000 km; vorb 29.78 km s-1; orbital period 365d.2564; e = 0.0167, i = 0; obliquity (1973) 2326'34". Albedo 0.

Hale-Bopp is a long-period comet that was discovered in 1995 and that reached perihelion in Spring, 1997.

In terms of orbital elements, NEOs are asteroids and comets with a perihelion (q) distance less than 1.3 times the Earth-Sun distance (AU).

Elements defining the shape of an orbit are the semi-major axis (a), orbital eccentricity (e) and perihelion distance (p).

" Perihelic means Mars is near perihelion--its closest distance to our Sun. Remember that the orbit of Mars, like that of all planets, is an ellipse, so the distance between the Sun and Mars changes as it goes around its orbit.

Pluto has an atmosphere when it is close to perihelion; the atmosphere may freeze out as Pluto moves farther from the Sun. It is thought by some that Pluto shares its atmosphere with its moon.

The cosmological constant will also cause a precession of the perihelion of a planet.

Apollo asteroids have semimajor axes (a) that are greater than or equal to 1 AU and perihelion distances that are less than or equal to 1.0 AU; thus, they cross the Earth's orbit when near the perihelia of their orbits.

149,597,870 km Perihelion
0.983 AU Aphelion
1.017 AU Eccentricity
0.01671022 Orbital period
365.25636 days Avg. Orbital Speed
29.7859 km/s Inclination
0.00005 Satellites
1 (the Moon) Satellite of
Sun Physical characteristics Equatorial diameter ...

It is at perihelion on January 2, at a distance 3% closer than aphelion in July. Climatic changes are closely linked to temperature variations.

Records of observations of Mars indicate that dust storms occur around the time of southern Summer Solstice (270 Ls), soon after perihelion passage (250 Ls).

After the comet reaches perihelion on November 28 and swings around the Sun, that's the end of the show for deep-southern observers. ISON will only become visible in the northern hemisphere from then onward.

Perihelion 147,098,074 km
0.9832898912 AU
Semi-major axis 149,597,887.5 km
1.0000001124 AU
Eccentricity 0.016710219
Orbital period 365.256366 days
1.0000175 yr
Average orbital speed 29.783 km/s
107,218 km/h
Inclination 134'43.

For example, if we consider an orbit just like that in the standard position, but with "perihelion" pushed back a degree, see that then the line of nodes will be on the y axis.

At its closest (perihelion), it is only 28.6 million miles from the Sun while, at its most distant (aphelion), it is 43.5 million miles. Its orbit perihelion moves backward (precesses) around the Sun at a very slow rate.

When Mars is at opposition and also near perihelion (Mars' closest approach to the Sun) -- as it was in August of 2003 -- the Martian opposition is especially close.

It had a perihelion of 0.29 AU and an aphelion of 1 AU. Its orbit made it an ideal platform for making long baseline time-of-arrival measurements to obtain source direction. The satellite rotated with a ~ 1-s spin period. The mission ended in 1981.

"We completed our first perihelion passage from orbit on Sunday, our first Mercury year in orbit on Monday, our first superior solar conjunction from orbit on Tuesday, and our first orbit-correction maneuver on Wednesday.

This time, the task is to decrease the periapsis (perihelion) of the spacecraft's present solar orbit. Recall from Chapter 3...
A spacecraft's periapsis altitude can be lowered by decreasing the spacecraft's energy at apoapsis.

Asteroid, Apollo: Asteroids with a semi-major axis greater than 1 AU but perihelion less than 1.017 AU.
Asteroid, Aten: Asteroids with a semi-major axis less than 1 AU.
Asteroid, Centaur: Asteroids that lie between the orbit of Jupiter and Neptune.

anomaly ((astronomy) position of a planet as defined by its angular distance from its perihelion (as observed from the sun))
periapsis; point of periapsis ((astronomy) the point in as orbit closest to the body being orbited) ...

The point at which a planet is closest to the sun is called perihelion. The farthest point is called aphelion. Image Credit: NOAA
View Larger Image → ...

It was known that it correctly accounted for the "anomalous" precession of the perihelion of Mercury and on philosophical grounds it was considered satisfying that it was able to unify Isaac Newton's law of universal gravitation with special ...

Periodic comets, also called short-period comets, have orbital periods of less than 200 years or which have been observed during at least one perihelion passage. Tail debris from some comets are what cause certain annual meteor showers.

See also: See also: Orbit, Sun, Earth, Planet, Solar

Astronomy  Perigee  Perihelion distance

 
RSS Mobile