Microlensing Einstein Radius Crossing Time Days Calculator
Point-lens Einstein-radius crossing time, geometric distances and effective transverse speed supplied; no event duration at a magnification threshold.
Description
Microlensing Einstein Radius Crossing Time Days Calculator: return einstein crossing days.
A microlensing crossing time divides an Einstein-radius length scale by transverse speed. The length depends on lens mass and lens-source geometry.
This tool returns einstein crossing days. 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.
For a foreground lens, compute sqrt[(4GM/c²) DL (1-DL/DS)], divide by transverse speed and then by 86400 for days.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| lensMassKg | Lens mass kg. Kilograms. | Finite number |
| lensDistanceM | Lens distance m. Meters. | Finite number |
| sourceDistanceM | Source distance m. Meters. | Finite number |
| transverseSpeedMPerS | Transverse speed m per s. Meters per second. | Finite number |
| Output field | Interpretation |
|---|---|
| result | Object containing the following named result fields. |
| result.einsteinCrossingDays | Einstein crossing days; use the stated units and sign convention. |
{
"input": {
"lensMassKg": 1e+30,
"lensDistanceM": 1000000000000000000,
"sourceDistanceM": 2000000000000000000,
"transverseSpeedMPerS": 100000
},
"output": {
"result": {
"einsteinCrossingDays": 4.4604986704467
}
}
}Limitations and assumptions
- The model uses a single geometric lens scale and constant transverse speed; it does not fit a light curve.
- 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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