Uncertainty of distance measurements for regions between 50-250 pc away

In summary: A parallax can be measured to a precision of 0.1 milliarcseconds and the Hipparcos catalogue has information on more than 1.3 million stars. So even if the error for a star is only +/- 0.0125pc, that still leaves us with an error of 0.00625pc which is amazing!
  • #1
Aiveenoka
7
0
Hi,

I am in the middle of a project dealing with the mass loss rate of protostars and hence I am working with the distance that these sources are away from us. I need to find the error in these distance measurements, however I cannot. In any paper (I find) that cites distances it just gives the number with no error values attached, and so I am wondering if there is a standard error in measuring the distance.

I am working with distances including 56pc (smallest), 140pc and 250pc (largest).

Thank you,
A
 
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  • #2
It depends on the object you measure and the telescope used for that.

The Hipparcos mission measured many stellar positions with an uncertainty of ~1milliarcsecond, this corresponds to the parallax of an object 2000pc away. If the parallax measurement has the same quality as the absolute position measurement (as relative measurement, I would expect a better accurary), this gives a relative uncertainty of ~1/80, ~1/14, ~1/8 for 56, 140, 250 pc respectively. GAIA is designed to improve parallax measurements to 10 microarcseconds*, reducing the relative error to <0.13% for the full range of your distances.

* similar to a coin (~2cm) on the moon
 
  • #3
Hi mfb,

Thank you for your reply.
The objects that have been measured are young stellar objects (YSOs) and unfortunately I don't know what was used to measure.
I had asked my supervisor about the error and he said it would be 5 or 10 pc or similar, however he is away now and so I cannot check anything with him. But I want to be able to back up my reasoning for taking the error to be whatever I use and I also didn't feel that I could "pick and choose" the errors, not to mention that the error for 56pc would be very different than for 250pc, hence I asked here.
When you say the error is about 1/80 for 56pc do you mean 56 +/- 0.0125pc ? If that is the case, that is amazing! Technology is fascinating!

Aiveenoka :)
 
  • #4
It is possible to measure distances with that precision. It does not mean that every star has been measured with that precision.

A quick search lead me to this website: The hipparcos catalogue has the parallax (H11) together with its standard deviation (H16) as parameters.
 
  • #5
Thank you very much mfb :)

It's amazing what is possible!
 

Related to Uncertainty of distance measurements for regions between 50-250 pc away

1. What is the significance of measuring distances between 50-250 pc away?

The range of 50-250 pc, or parsecs, is a crucial distance for scientists studying stars and galaxies. It falls within the realm of our own Milky Way galaxy and allows for more accurate measurements compared to much greater distances, making it a key range for understanding the structure and evolution of our galaxy.

2. How is the uncertainty of distance measurements calculated?

The uncertainty of distance measurements is calculated by taking into account various factors, such as the precision of instruments used, the quality of data collected, and the statistical methods employed. It is important to note that uncertainty is always present in scientific measurements and is often expressed as a margin of error.

3. What are some common sources of error in distance measurements?

Some common sources of error in distance measurements include atmospheric effects, instrumental limitations, and the presence of interstellar dust and gas. These factors can affect the accuracy and precision of measurements, leading to uncertainty in the final results.

4. How can scientists reduce uncertainty in distance measurements?

To reduce uncertainty in distance measurements, scientists employ various techniques such as using multiple instruments and methods to cross-check results, improving the precision of instruments, and accounting for potential sources of error. Additionally, larger sample sizes and more precise data can also help to reduce uncertainty in measurements.

5. How does uncertainty in distance measurements affect scientific research?

Uncertainty in distance measurements can have a significant impact on scientific research, particularly in the field of astrophysics. It can affect our understanding of the structure and properties of stars and galaxies, as well as our ability to make accurate predictions about their evolution. Therefore, it is crucial for scientists to continually improve distance measurement techniques and reduce uncertainty in order to advance our knowledge of the universe.

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