Combust Planets | Astro 2023

Discover how combust planets can alter our energy

Combustion is defined by a planet’s relationship to the Sun and is a part of a planet’s synodic or solar- phase cycle. It occurs when a planet is close to the Sun and is invisible. The origins of combustion take us back to early Greek and Babylonian star lore, which was adapted for use with the planets by Hellenistic astrologers.

When a planet is combust the Sun, the power of the Sun dominates the light and energy of that planet. This leads to the planet expressing and manifesting differently than it otherwise would if it were not near the Sun.

Themes of light and darkness, of being hidden or being seen, were important to ancient astrologers. The theories relating to combustion flow forth from this. Working with combustion involves identifying when a planet moves through a phase of invisibility, which requires adjusting the meaning of a planet to reflect this. A conjunction with the Sun is different to and distinct from a conjunction between any two other planets, angles or points in the chart, as during this conjunction a planet becomes temporarily invisible

As the Sun is the main source of wisdom, a planet close to the Sun has special access to wisdom and insight. This can be a function or offering of a planet combust. Having access to this wisdom or insight won’t take away from any of the typical challenges you might experience of a planet combust, but it can show you also have access to awareness, wisdom, perspective, insight and understanding that can be shared to help or guide others.

Obscure and hidden: combust qualities

Since a combust planet is hidden, topics and themes linked to that planet can be obscured. This could show up as experiencing a type of blindness relating to this planet or its topics. You may not be able see them clearly, or you get surprised by events or experiences you didn’t know you were missing. It might mean some of the topics associated with a planet combust in your chart are areas of life where you experience some lack or dissatisfaction, or that describe topics and areas of life where you aren’t seen or accepted as you are.

Since combustion focuses on a planet’s period of invisibility, it’s a consideration that only applies to the original planets, those that can normally be seen with the naked eye. This includes Saturn, Jupiter, Mars, Venus, Mercury and the Moon. Combustion doesn’t apply to the newer or modern planets, Uranus, Neptune or Pluto, or to sensitive points in a chart like the angles or nodes.

Each planet meets the Sun and moves into and out of combustion on a regular cycle. For Venus, Jupiter and Saturn that is usually once a year. For Mars, it’s once every two years. Mercury meets the Sun multiple times a year. The Moon meets the Sun every four weeks.

Three ways with the Sun

I think of a planet conjunct the Sun in three ways, depending on just how close to the Sun that planet is. Combustion is one of these three states. The other two are cazimi and under the Sun’s beams. Each of these states is defined by a planet being close to but at a different specific distance from the Sun. Each term defines a slightly different relationship to the Sun.


A planet is cazimi when it is most tightly conjunct the Sun. There are two technical definitions of cazimi. The tightest definition is when a planet is within 17 minutes of the Sun and comes from the Medieval astrologers. The second definition, from the earlier Hellenistic period, defines a planet as cazimi when it is up to 1 degree either side of the Sun.

A planet cazimi the Sun is elevated and amplified. This is a favourable condition for a planet. Anything represented by a planet cazimi has the potential to manifest to the benefit of the individual. When cazimi, a planet is said to be protected from any of the blinded or obscuring effects of combustion.

A planet cazimi is in the heart of the Sun, as if the Sun gives its favour to the planet and holds it close to its heart. This is like a planet having special access to royal coffers and resources to support it on its mission.

Being cazimi centres and strengthens the themes of the planet and can mean these themes and topics become dominant in the chart and in life. It’s common for the individual to enjoy a special skill, talent or favour based on topics and tasks relating to a planet combust.

Oprah Winfrey has Venus cazimi the Sun in Aquarius in her 3rd house. She also has a Libra MC in the whole sign 11th house. One simple interpretation of this is that career, as ruled by Venus, is an area of potential success, elevation and satisfaction


A planet combust is outside the cazimi zone, within 8 degrees of the Sun. There is some debate as to whether combustion should be a little more or a less than 8 degrees, but as a guideline, 8 degrees is useful.

A planet combust is not able to care for their usual tasks or topics and these areas of life may suffer from a lack of attention, clear thinking or being overlooked. Having a combust planet isn’t a barrier to success but it can help you identify pain points you might have to navigate.

Themes of blindness show up relating to a planet combust. If you have a combust planet, you might miss or not see what appears obvious to others around these topics and areas of your life. This planet might describe a blind spot or a shortcoming you learn to manage throughout your life. You might experience the topics of any planet you have combust as being ineffective or irregular, or as areas of life that require extra attention and effort to keep steady and operational. Engaging with a combust planet will require nuance and subtlety, as well as developing profound self awareness.

A combust planet operates under a type of cloak of invisibility. While this can mean there may be concerns regarding not being seen or not seeing, it also provides for the ability to act in secret, or to operate in a way that is hidden from view. If you were wearing a blindfold, you might find it hard to walk around an unknown room, but it might be easier to do something crafty with your hands underneath the cloak.

Since combustion is defined by a planet’s nearness to the Sun, combustion will apply even if the Sun and the planet are in different signs. As long as the planet and the Sun are within the 1-8-degree range, the influence of combustion will be in play.

Imagine a client has the Sun at 27 Cancer and Mars at 3 Leo. Even though these planets are in different signs, the influence of combustion will apply, as the planets are only 6 degrees apart. It will influence the topics of the house Mars is placed in, as well as the two houses ruled by Mars, that is, the two houses that have the signs of Aries and Scorpio on the cusp.

Under the Sun’s beams

A planet that is outside the combustion zone but still within approximately 15 degrees of the Sun is under the beams. The exact degree distance a planet needs to be from the Sun to be seen or become visible again varies based on the brightness of the planet, atmospheric conditions and geographic location, so the 15-degree marker is a guide rather than an exact measurement.

A planet under the beams is less harmed compared to a planet combust, but remains invisible and less effective. A planet under the beams is still in a state of restriction and reduced function/effectiveness, though it’s not quite so limiting or restrictive as if the planet were combust.

Purification and ritual

As a planet becomes invisible and moves into and through these three states, it joins with the Sun and undergoes a type of purification process, like a ritual burning or cleansing.

Ancient Egyptians considered this a type of death, becoming invisible, and then a rebirth when visible again. This process can lead to a dismantling of topics and expression of the planet for a period of time before a re-emergence brings forth new potential.

If you are born with a planet in one of these three states, it is deep into its purification process, like a devotee taking time out of regular life to attend temple or undergo a ritual rebirth. While the effects of combustion or being under the beams can be challenging, the links to this mystical purifying and rebirth sequence can highlight spiritual matters or topics as generally being of interest.

Getting technical: movement

It is appropriate to consider whether a planet is moving closer to the Sun, into combustion, or whether a planet is moving away from the Sun and out of combustion. These are more technical considerations that may be useful for more advanced readers to consider.

If you’re new to the idea of combustion, learning the concept and figuring out how to weave combustion into your chart interpretation will be an important starting point.

Combustion in a birth chart

Not every chart will have a planet combust. Some charts will have more than one planet combust. For example, renowned musician Pink has Mercury, Saturn and Venus combust the Sun in Virgo.
When working with a combust planet, it’s important to identify the exact topics and themes that are tied to the planet, so you can correctly describe and interpret the ways in which the combust planet might influence the chart and life.

While there are some common topics to each planet, such as love, relationships and self-worth for Venus, or confidence and assertiveness with Mars, there will also be specific topics attached to each planet based on the houses in which their signs are placed in any given chart.

To make sure you collect all the topics that may be influenced by a combust planet, check the houses that have the following signs on the cusp for each planet in the table below.

Planets, topics and houses

It’s common to see some of the general topics and concepts of a planet strongly emphasised in the life of an individual with a combust planet, as if the tone and qualities of the planet infuse the Sun and become an important part of their identity. These topics and themes may become part of the central principles for the individual, around which much of their life and focus is centred.

The topics of the houses ruled by a planet combust are often where some of the biggest challenges, limitations or blocks can be found. Make sure to check the specific house where you have each of these signs, in your own chart, or the chart of the person you’re working with, and avoid defaulting to the generic Aries-rising chart format.

A client example

A client has Mercury combust, just 2 degrees from the Sun. They have an Aquarius rising, with the Sun and Mercury in Taurus. The Sun is at 11 Taurus and Mercury is at 9 Taurus. In this chart, Mercury is in charge of the 5th and the 8th houses, where Mercury’s signs of Gemini and Virgo reside. Mercury is placed in the 4th House, alongside the Sun.

As Mercury is combust, this client might struggle to clearly express themselves or be heard by others. They may need to review or repeat themselves, to make sure that what someone else heard is what they said. They may feel their voice isn’t heard in family settings (as Mercury and the Sun are in the 4th House of home and family), or that someone else in the family has a louder or more dominating presence in comparison, making them feel unseen or overlooked, as if who they are is not fully appreciated or understood by the family.

In addition, they may experience some challenges regarding hidden information, blocks or hard-to-solve problems around 5th House topics such as children, fertility, creativity and having fun, or dealing with 8th House matters like money, taxes, debt, their partner’s finances, their own psychological state and more.

This client struggled for years to conceive. Later in life, she was finally able to give birth to a much-longed- for child. In addition, they had dealt with stressors relating to their partner’s income and tax situation, which caused tension and challenges for them both as a couple.

The gifts of a combust planet

I like to think of a planet combust operating in a liminal place, like the inner workings of the mind and psyche, or in the places where energetic awareness and intuition reside. A planet combust may not be helpful for managing and organising practical, real-world matters that rely on time, structure and clarity — those constructs of an organised, functional and structured world — but they may be uniquely useful in the realms of psychology, the psychic and emotional fields, as well as in creative areas.

There are numerous examples of successful individuals with a combust planet. They excel in a range of fields that rely on a strong sense of the intangible and a willingness to work in ways that draw on awareness of the unseen and the sensed, where things aren’t certain but where possibilities and sensation hold value. Planets that are combust may hold special gifts for helping or encouraging you to dive inside, to explore and get to know the inner workings of yourself or others.

As you navigate life with a combust planet, you may learn to find your way through the dark and may develop a strong instinctive sense. This might mean you’re more comfortable in places of darkness or in states of uncertainty than some of your peers, friends, family or clients might be.

If you have a planet combust, you may benefit from cultivating a connection with your own emotional state or from learning about human behaviour and feelings. In this way, a planet combust can reveal skills, gifts or talents relating to emotions or with intuition and creative inspiration, like tapping into the sometimes obscure but still potent messages from the muses.

Another of my clients has the Sun conjunct Mercury in Virgo in the 6th House. Mercury is at 19 Virgo and the Sun is at 21 Virgo. Mercury rules the third and sixth houses, making a tight trine aspect to the MC, which is in Capricorn.

While this client has dealt with their own anxiety and had to learn how to manage their busy mind, they also excelled in their chosen field of psychology, helping to care for and guide others in how to manage their own minds and mental state.

The impact of the ruling planet on combustion

In traditional styles of astrology, the ruler of something impacts how that thing expresses, in terms of how helpful and supportive to the person a placement might be or how much of a hindrance or distraction it might be. Here’s an example that illustrates this.

Let’s compare the charts of Princess Diana and a client. Both have a Sagittarius rising and Gemini on the descendant. This means that Mercury will be the ruling planet of the 7th House in both charts and in charge of the topic of relationships.

Princess Diana had Mercury retrograde at 3 Cancer in the 8th House, with the Sun at 9 Cancer, making Mercury combust. All the concerns of combustion, about not seeing events or circumstances clearly, are in play and relate to the topic of relationships and marriage.

Princess Diana had the Moon — the ruler of the Sun conjunct Mercury aspect and combustion in Cancer — in Aquarius conjunct the South Node. Being in Aquarius is not the concern here, the Moon’s proximity to the South Node is. This is a depleting, diminishing influence for the Moon, which severely limits the Moon’s ability to help out or make up for any lack of clarity indicated by Mercury being combust.

As her marriage to Prince Charles unravelled, Princess Diana famously talked about how there were three people in their marriage as she slowly came to see what many around her already knew, that Prince Charles was in love with Camilla.

Comparatively, my client has the Sun and Mercury in Taurus in the 6th House in their chart. The Sun is at 2 Taurus and Mercury is at 10 Taurus. Like Diana, the concerns and considerations of combustion will affect Mercury and will influence the topics of relationships and marriage. However, in this instance, the Sun conjunct Mercury aspect and combustion is ruled by Venus, who herself is in Taurus at 23 degrees.

Here, the combust planet of Mercury is ruled by a planet, in this case Venus, with more to offer. The benefits Venus has available from being in one of her home signs, with access to resources, and her general inclination to help stabilise matters and support accumulation, has more of a helpful influence, going some way to fortify and make up for some of the shortcomings of Mercury combust.

This isn’t a perfect remediation, and doesn’t take away from the fact that Mercury is invisible and will still miss things, but it does show the missing of things, as indicated by combustion, to be less destructive or harmful, or at least have lesser effects or consequences.

This client had a long marriage before separating from their spouse. In the client’s case, their spouse was consumed by their career, leaving little time for their marriage or family life.

Being aware of some of these different qualifications around combustion may encourage you to keep an open mind for the varying ways in which a combust planet might manifest, as well as some of the qualifying factors around what might make a combustion more difficult than expected, or less harmful than anticipated.

Going within, moving forward

A lot has been written about combustion that can make you fear having a planet in this state. Keep in mind there is always space between the theory on the page and the lived experience of a chart placement. I hope that by coming to understand the specific challenges a combust planet might have, as well as any particular insight it may offer, you’ll be able to work with any combust planet holistically.


Article featured in WellBeing Astrology 2023 

Kelly Surtees

Kelly Surtees

With more than 14 years in private practice, Kelly Surtees is experienced, warm and insightful. She loves exploring astrology’s history as well as escaping into the ocean. Kelly’s passion for astrology is infectious, and her specialty areas include career and life direction, health and fertility, love, health and happiness. Kelly is an expat Aussie who lives in Canada most of the year.

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