In Vedic astrology, when a planet comes too close to the Sun (in terms of the degrees), it is combusted. Combustion here refers to the loss of the said planet’s strength due to being burnt by the Sun’s heat. Except Rahu and Ketu, all planets can be combust. The table below shows the degrees within which the planets suffer combustion and lose some of their strength.
A planet that is combusted by the Sun loses approximately up to 50% of its power to benefit the respective ascendant chart or horoscope. Some books may say it destroys 90% of the power, but that is not true. This is because this figure may be less if the said planet is well-placed, meaning it is either in a friendly or own zodiac sign, or is aspected by a benefic, etc.
| Planet | Combustion in Direct Motion | Combustion in Retrograde Motion |
| Moon | 0 to 12 degrees | N/A, Moon cannot be retrograde |
| Mars | 0 to 17 degrees | 0 to 8 degrees |
| Mercury | 0 to 14 degrees | 0 to 12 degrees |
| Jupiter | 0 to 11 degrees | 0 to 11 degrees |
| Venus | 0 to 10 degrees | 0 to 8 degrees |
| Saturn | 0 to 16 degrees | 0 to 16 degrees |
*Neptune, Uranus, and Pluto do not get combust by the Sun since they are the farthest planets away from the Sun.
**Prior to popular belief, Mercury, Venus, and Saturn can all be combust. Mercury combusts up to 14 degrees in direct and 12 degrees in retrograde motion, Venus combusts in 0 to 10 degrees difference in direct motion and 0 to 8 degrees in retrograde motion.
Example #1
- Sun – 29 degrees, Virgo
- Mercury (Direct) – 18 degrees, Virgo
Difference – 29 – 18 = 11 degrees difference; this falls in the 0 to 14 degrees range, so Mercury is combust.
Example #2
- Sun – 28 degrees, Virgo
- Mercury (Retrograde) – 5 degrees, Libra
Difference = 30 – 28 degrees (each sign has 30 degrees) = 2 degrees, and 5 – 0 degrees in Libra = 5 degrees. So, total difference is 2 + 5 = 7 degrees, which falls under the 0 to 12 degrees difference range, so Mercury is combust.
***Note that when the Sun is placed 28 degrees in Virgo, and Mercury is placed 5 degrees in Libra, combustion still counts because the Sun is literally 7 degrees away from Mercury, which is 5 degrees in Libra (0 to 5) and 2 degrees in Virgo (28 to 30).