Radial Velocity Semi-Amplitude K m/s Calculator
Keplerian two-body stellar radial-velocity semi-amplitude in m/s with full total-mass denominator; no detectability/activity model.
Description
Radial Velocity Semi-Amplitude K m/s Calculator: return semi amplitude m per s.
A radial-velocity semiamplitude measures the size of a periodic line-of-sight velocity variation. Mass, period, inclination and eccentricity affect it.
This tool returns semi amplitude m per s. Use the stated units and model convention when interpreting these fields.
When to use this tool
Use this tool when the supplied inputs match the specific operation described above and you need a repeatable result under its stated convention.
- Check the supported input and output contract against an existing calculation or observation.
- Use the complete example to confirm units, selector spelling and result interpretation.
How to use the tool and how it works
- Enter every field in the input table using the stated units and the exact supported selector spelling where applicable.
- Run the tool. Correct input errors before interpreting an output.
- Read the result fields below; use accompanying flags and the stated sign, boundary or model convention when interpreting a number.
Evaluate (2πG/P)^(1/3) times planet mass times sin(inclination), divided by total mass^(2/3) and sqrt(1-e²).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| periodSeconds | Period seconds. Seconds. | Finite number; greater than zero |
| planetMassKg | Planet mass kg. Kilograms. | Finite number; zero or greater |
| starMassKg | Star mass kg. Kilograms. | Finite number; greater than zero |
| inclinationDegrees | Inclination degrees. Degrees. | Finite number; from 0 to 180 inclusive |
| eccentricity | Eccentricity. | Finite number |
| Output field | Interpretation |
|---|---|
| result | Object containing the following named result fields. |
| result.semiAmplitudeMPerS | Semi amplitude mper s; use the stated units and sign convention. |
{
"input": {
"periodSeconds": 100000,
"planetMassKg": 100000000000000000000,
"starMassKg": 1e+30,
"inclinationDegrees": 90,
"eccentricity": 0
},
"output": {
"result": {
"semiAmplitudeMPerS": 0.000016126069628360346
}
}
}Limitations and assumptions
- The model is Keplerian with 0 ≤ e < 1 and angles in degrees. It does not fit stellar activity or multiple companions.
- Every declared field is required and unexpected fields are rejected. Numeric inputs must be finite; input errors are distinct from a valid false result or an explicitly qualified output.
- Extremely large inputs and nonfinite or excessively large outputs are rejected. List positions reported by the tool use zero-based indices unless stated otherwise.
Alternative or Complementary methods
Check the underlying observations, units and conventions independently before using the result in a larger workflow. The tools listed below address nearby tasks; compare their inputs and scope before substituting one for this operation.
References
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