A planet is combust, Ast or Astangata in Sanskrit (literally body hidden), when it sits so close to the Sun in the sky that its light is lost in the solar glare. Classical texts read this as a planet losing its independent voice -- its natural significations continue to operate, but filtered through the Sun's dominance rather than expressed on their own terms. Combustion is a separate check from Shadbala and dignity, sitting alongside them in a full suitability analysis rather than being a sub-component of either, and it is one of the more commonly overlooked factors in casual gemstone advice that stops at Lagna alone.
The Combustion Degrees for Each Planet
Six of the nine planets can become combust; the Sun cannot combust itself, and Rahu and Ketu, having no physical body, are exempt entirely. The classical orbs, measured as angular distance from the Sun, are commonly cited as:
- Moon: within 12 degrees
- Mars: within 17 degrees (8 degrees when retrograde)
- Mercury: within 14 degrees (12 degrees when retrograde)
- Jupiter: within 11 degrees
- Venus: within 10 degrees (8 degrees when retrograde)
- Saturn: within 15 degrees
These figures come from Brihat Parashara Hora Shastra and Phaladeepika, and are widely but not perfectly consistent across secondary sources -- a few cite Mercury at 13 rather than 14 degrees, for instance -- so treat the exact boundary as approximate rather than laboratory-precise, the same caveat that applies to several other degree-based classical measurements. Notice that the two natural malefics among the six, Mars and Saturn, have the widest orbs (17 and 15 degrees), while the two naturally gentle planets closest to the Sun in real orbital terms, Mercury and Venus, have narrower orbs that tighten further still when either is retrograde -- a pattern classical commentators tie to Mars and Saturn's already-forceful nature needing a wider berth before the Sun's influence genuinely overwhelms them.
Why Mercury and Venus Are Combust Most Often
Mercury and Venus orbit between Earth and the Sun and never appear far from it as seen from our vantage point -- Mercury stays within roughly 28 degrees of the Sun and Venus within roughly 47 -- which means these two planets pass in and out of combustion repeatedly and are, in practice, combust in a meaningfully larger share of birth charts than Mars, Jupiter or Saturn. The Moon, by contrast, is combust only briefly, for roughly two days around each new moon, since it orbits Earth rather than the Sun and moves through the full zodiac in about a month. Mars, Jupiter and Saturn, being genuinely farther from the Sun in orbital terms, spend comparatively little of each cycle close enough to combust, which is part of why combustion checks matter disproportionately for Mercury and Venus specifically when evaluating Panna and Heera.
What Combustion Actually Does
Classical texts frame combustion as something close to a planetary war the combust planet cannot win -- the Sun's brightness overwhelms the weaker light of the combust planet, and its results become harder to see operating independently. This is not the same as destruction, however: a combust planet's significations do not disappear, they simply express less visibly, more slowly, or more privately, and strong dignity in the same placement can preserve much of the planet's underlying power despite the affliction. An exalted planet that also happens to be combust, for instance, is a genuinely different case from a debilitated planet that is also combust, even though both are technically Ast -- combustion dims whatever strength or weakness a planet already carries, rather than resetting it to some fixed neutral baseline. This is a genuinely separate concept from Graha Yuddha (planetary war), where two planets sit within one degree of each other and classical texts assess a winner and loser between them directly -- combustion specifically concerns a planet's relationship to the Sun, not to any other planet.
Budh-Aditya Yoga: When Combustion Isn't Entirely Bad News
Mercury combust with the Sun is specifically named in classical texts as Budh-Aditya Yoga, and it carries a notably better reputation than combustion generally does -- this specific conjunction is often read as conferring intelligence, communication skill and analytical sharpness, treated in some classical readings as a minor Raja Yoga rather than a pure affliction. This is a genuinely useful exception to keep in mind: combustion is not a uniformly negative label applied identically to every planet, and Mercury's particular relationship with the Sun is read more charitably than Mars, Saturn or Venus combustion typically are. The nuance even goes a step further in some classical treatments: Mercury combust while very close to exact conjunction (within roughly one degree) is sometimes read as especially auspicious, described as Mercury being embraced by the Sun rather than merely overpowered by it, a distinction most generic gemstone advice never mentions.
Why Combustion Matters for Gemstone Selection
A functional benefic that is combust is a weaker recommendation than the same functional benefic uncombust, since its ability to deliver on its favourable house lordship is dimmed by the affliction -- this is one of the more common reasons a stone that looks favourable purely from Lagna analysis underperforms in an individual chart. Combustion does not change functional status itself, the same way dignity does not -- a combust functional malefic is still a functional malefic, and in some readings its already-difficult influence becomes harder to counteract precisely because it operates less visibly. Practically, this means combustion works in the opposite direction depending on functional role, mirroring how Shadbala and dignity behave: a combust functional benefic generally needs more caution before its gemstone is worn with full confidence, while a combust functional malefic does not become safer simply because its influence is dimmed -- a malefic operating quietly is not necessarily a malefic operating less. This is exactly the kind of chart-specific factor that a Lagna-only reading cannot see, and why Trikaal Vaani's free Gemstone Suitability Calculator checks combustion alongside functional status, Shadbala and dignity rather than treating any single factor as sufficient on its own.
Common Misconceptions About Combustion
A combust planet is completely powerless -- not accurate; combustion dims a planet's independent expression, but strong dignity or other supporting factors can preserve much of its underlying strength, and the planet's significations continue operating rather than vanishing. Every planet combusts at the same distance from the Sun -- no, each of the six combustible planets has its own specific orb, ranging from roughly 10 degrees for Venus to 17 for Mars, and Mercury and Venus additionally have tighter orbs when retrograde. Mercury combust is always a problem -- not necessarily; Budh-Aditya Yoga treats Mercury-Sun conjunction as a genuinely favourable combination in many classical readings, unlike combustion involving other planets. The Sun and the nodes can also become combust -- no, the Sun is the source of combustion rather than a subject of it, and Rahu and Ketu, being shadow points without physical bodies, are exempt from this affliction entirely. Combustion and retrograde motion are the same thing -- no, they are entirely separate conditions describing different aspects of a planet's apparent motion and position, and a planet can be combust, retrograde, both, or neither, independently of each other.
Worked Example: A Favourable Stone Undercut by Combustion
Consider Jupiter for Pisces Lagna, discussed on our Pisces Lagna gemstone guide -- Jupiter is both Lagnesh and posited in its own sign there, making it the strongest possible functional-benefic case the system produces on paper. But if that same native's actual Jupiter happens to sit within 11 degrees of the Sun, it is combust, and even this strongest-case planet's practical delivery is dimmed by the affliction. This does not erase Jupiter's favourable status -- a combust functional benefic is still a functional benefic -- but it is precisely the kind of chart-specific detail that separates a genuinely personalised suitability score from a Lagna-only recommendation that stops at house lordship alone. The same logic runs in reverse for a functional malefic: combustion dimming an already-difficult planet's visible influence is not the same as neutralising the difficulty itself, which is why a full suitability check treats combustion as a modifier on existing functional status rather than a verdict of its own.
Quick Reference: Checking Combustion Yourself
One question covers the basic check: how many degrees separate this planet from the Sun in your exact chart, and does that fall inside the orb listed above for this specific planet? A combustion calculator answers this instantly from your birth details rather than asking you to calculate angular separation by hand, and it automatically applies the tighter retrograde orbs for Mercury and Venus when relevant, a detail that is easy to miss in a manual check.
Combustion and Dasha Timing
A combust planet's dimmed influence matters most in practice during that planet's own Mahadasha or Antardasha, when its significations are already centre stage regardless of how visibly they express. A combust functional benefic running its own dasha period is a case where the combustion genuinely earns closer attention, since the native is living through that planet's themes at exactly the time its independent voice is hardest to hear -- one more reason combustion is checked alongside Dasha context rather than in isolation, similar to how it is checked alongside Shadbala and dignity elsewhere in this series.
Combustion in a Full Suitability Score
Trikaal Vaani's free Gemstone Suitability Calculator treats combustion as one weighted input among several rather than a single deciding factor -- a combust functional benefic with otherwise excellent Shadbala and dignity can still score comfortably in the favourable range, while a combust functional benefic that is also weak on every other measure compounds into a genuinely borderline case. Reading any one factor in isolation, combustion included, risks either dismissing a stone too quickly or trusting it more than the fuller picture supports.
Why Combustion Alone Rarely Settles a Verdict
A combust planet's status changes month to month for the fast-moving planets and much more slowly for Saturn, which means the same natal placement is permanently combust or permanently clear -- birth combustion, unlike a transiting one, does not change over a lifetime. This permanence is exactly why it deserves the same one-time, careful check as dignity, rather than being treated as a minor afterthought once functional status and Shadbala have already been reviewed.
The Takeaway
Combustion answers one specific question -- is this planet's light currently overwhelmed by the Sun -- and like dignity, it always needs pairing with functional status to mean anything practical. A combust functional benefic loses confidence; a combust functional malefic does not gain safety.
Summary
Combustion dims a planet's light, it does not erase its underlying power. Always check it alongside functional status, Shadbala and dignity, never in isolation, and the resulting picture will consistently be more accurate than any single-factor shortcut could genuinely ever hope to be entirely on its own.
Where to Go Next
For the strength question combustion feeds into, see our Shadbala page. For the sign-placement question that runs alongside it, see our Planetary Dignity page. For the functional question either always needs pairing with, see our Functional Benefic and Malefic page. For the combined answer across all of these, use the calculator below.
A Closing Thought on Visibility Versus Absence
The most important reframe this page offers is that combust does not mean gone. Treating a combust planet's stone as automatically worthless throws away a functional benefic that may simply need its case made more carefully, while treating combustion as harmless ignores a real, measurable dimming that a proper suitability check is built to weigh correctly, in exact combination with functional status, Shadbala and dignity, rather than round to zero or ignore entirely on its own.
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✦ Check If Your Planet Is Combust Free ->Brihat Parashara Hora Shastra; Phaladeepika -- Astangata chapter