In orbital mechanics, the minimum distance of a planet from the Sun during its elliptical orbit is known by which specific term?

Introduction / Context:
Planets move around the Sun in elliptical orbits, so their distance from the Sun changes during one revolution. The points of minimum and maximum distance have special names. Knowing these terms is essential in astronomy and helps in understanding seasonal variations and orbital mechanics. This question asks for the name of the point where a planet is closest to the Sun in its orbit.

Given Data / Assumptions:

• Planetary orbits around the Sun are elliptical, not perfectly circular.
• The Sun occupies one focus of the elliptical orbit.
• Two key points are defined: one for minimum distance and one for maximum distance.
• The options also include terms used for Earth Moon distances.

Concept / Approach:
The term perihelion comes from peri meaning near and helios meaning Sun. It denotes the point in the orbit of a planet where it is closest to the Sun. The opposite point, where the planet is farthest from the Sun, is called aphelion. Apogee and perigee are similar terms used for the distance between the Earth and the Moon or artificial satellites, with apogee as the farthest point from the Earth and perigee as the nearest. Therefore, for a planet orbiting the Sun, perihelion is the correct term for the minimum distance point.

Step-by-Step Solution:
Step 1: Recognise that the question refers specifically to the distance between a planet and the Sun. Step 2: Recall that perihelion is the point where the planet is nearest to the Sun. Step 3: Remember that aphelion is the farthest point from the Sun for a planet. Step 4: Note that apogee and perigee are used in the context of orbits around the Earth, not orbits around the Sun. Step 5: Choose perihelion as the correct term for the minimum distance from the Sun in a planet orbit.

Verification / Alternative check:
Astronomy references and descriptive texts of planetary orbits consistently state that the Earth is at perihelion around early January and at aphelion around early July each year. Similar descriptions apply to other planets. On the other hand, satellite orbit descriptions around the Earth talk about perigee and apogee instead. This clear separation of terms supports the use of perihelion for the closest planet Sun distance.

Why Other Options Are Wrong:
Option b, aphelion, is the point where the planet is farthest from the Sun, not the nearest.

Option c, apogee, refers to the point farthest from the Earth in the orbit of the Moon or a satellite.

Option d, perigee, refers to the point nearest to the Earth in the orbit of the Moon or a satellite, not to distances involving the Sun.

Common Pitfalls:
Because perihelion, aphelion, perigee and apogee sound similar, learners often mix them up. A helpful trick is to associate helion with the Sun and gee with the Earth, and to remember peri for near and apo for far. With these roots in mind, you can quickly pick perihelion as the closest distance to the Sun and aphelion as the farthest, while perigee and apogee are reserved for Earth related orbits.

Final Answer:
The minimum distance of a planet from the Sun in its orbit is called Perihelion.