Home › Learn Astrology › Transits
Combust Planets Explained
Lesson 83 of 100 · Transits
Log in or join free to track your progress through the course.
When a planet sits very close to the Sun in the zodiac, Vedic astrology calls it combust, or asta. The Sun is the brightest body in the sky, and a planet near it is figuratively burnt by that glare, much as you cannot see a candle held next to a floodlight. A combust planet keeps its position and its significations, but it loses the strength to express them clearly. This lesson covers what combustion means, the approximate degree distances at which each planet becomes combust, the effects on the planet's themes, and why Mercury and Venus end up combust so often.
What Combustion Means
Combustion, or asta, describes a planet that is too close to the Sun within the same chart, measured by the gap between the two in degrees of longitude. The Sun does not change what the planet stands for, but it overpowers the planet's ability to act on its own terms.
Think of a singer trying to be heard next to a roaring engine. The voice is still there, but it gets drowned out. A combust planet behaves similarly: its significations remain in the chart, yet they tend to come through weakly, anxiously, or tangled up with the Sun's themes of ego, authority, and self. The planet works in service of the Sun rather than freely.
Approximate Combustion Orbs
Different planets are said to combust at different distances from the Sun, and the exact figures vary between texts. A widely used set of approximate orbs is as follows: the Moon within about 12 degrees, Mars within about 17 degrees, Mercury within about 14 degrees (and around 12 degrees when retrograde), Jupiter within about 11 degrees, Venus within about 10 degrees (and around 8 degrees when retrograde), and Saturn within about 15 degrees.
These numbers are not universal, so a careful astrologer treats them as guidelines rather than hard cut-offs. A planet a fraction of a degree outside the orb is not suddenly unharmed, and one near the centre of the orb feels the effect most strongly.
Effects on the Combust Planet
The core effect of combustion is reduced strength in the significations of the combust planet. If Mercury is combust, the areas Mercury governs, such as communication, reasoning, and trade, may feel uncertain or underconfident. If Venus is combust, themes of relationships, comfort, and harmony can become strained.
Because the Sun is involved, those significations often get coloured by self-image and pride. A combust Mars might show as a temper that flares from wounded ego rather than steady courage. The honest reading is not that the planet stops working, but that it works under pressure and rarely with full freedom.
Why Mercury and Venus Are Often Combust
Mercury and Venus are the two planets that never stray far from the Sun in the sky. Mercury always stays within about 28 degrees of the Sun, and Venus within about 47 degrees, because both orbit closer to the Sun than Earth does. As a result, they frequently fall inside the combustion orb.
This means combust Mercury and combust Venus are common, and an astrologer should not over-read them as rare disasters. Other factors, such as good dignity, helpful aspects, or the planet being a yogakaraka for the chart, can soften or offset the burning. Combustion is one signal among many, not a verdict on its own.
Key takeaways
- Combustion, or asta, occurs when a planet sits too close to the Sun and its light is overwhelmed.
- The combust planet keeps its significations but loses the strength to express them clearly and freely.
- Approximate orbs differ by planet: Moon about 12 degrees, Mars 17, Mercury 14 (12 retrograde), Jupiter 11, Venus 10 (8 retrograde), Saturn 15.
- A combust planet's themes often get coloured by the Sun's ego and self-image.
- Mercury and Venus stay near the Sun by nature, so they are combust frequently and should not be over-read.
Knowledge check
6 quick questions on this lesson. Answer all, then submit to see your score and explanations.