X-ray trigonometric parallax/Quiz

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VLA 90-cm wavelength image, adapted from LaRosa et al. (2000), with the locations of Sgr A*, Sgr B2, and J1745–2820 indicated. Credit: M. J. Reid, K. M. Menten, X. W. Zheng, A. Brunthaler, and Y. Xu.

X-ray trigonometric parallax is a lecture about the theoretical possibility of using higher resolution X-ray detectors to measure stellar parallaxes. It is also a mini-lecture for a quiz section as part of the department of radiation astronomy course on the principles of radiation astronomy.

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Quiz[edit | edit source]


1 Yes or No, Distance measurement by parallax is a special case of the principle of triangulation.


2 Trigonometric parallax involves which of the following?

reciprocal of parallax
apparent changes in position
lines of sight

3 Copernicus's theory provided a strikingly simple explanation for the apparent retrograde motions of the planets—namely as


4 Radiation phenomena associated with trigonometric parallax are

gamma-ray trigonometric parallax distances < 0.4 kpc
X-ray trigonometric parallax distances good to 2 pc
ultraviolet trigonometric parallax is good to ± 7 pc
visual trigonometric parallax distances good to about 3 kpc
infrared trigonometric parallax with an accuracy of 120 µas
radio trigonometric parallax distances good at least to 1.86 kpc

5 Complete the text:

Trigonometric parallax measurements of

pulsars are the reliable


6 Complete the text:

Match up the type of trigonometric parallax with each of the possibilities below:
visual parallax - A
distribution function of the errors in distance - B
Cygnus X-1 - D
pulse times of arrival - E
ultraviolet trigonometric parallax - F
optical annual parallax (HST) - G
continuum 'fixed' radio sources J1953+3537 and J1957+3338

Vela pulsar

skewed due to non-linearity

cloud top height

Sgr B2M and Sgr B2N

PSRs J1744−1134 and J1024−0719 detected at X-ray energies

χ Cyg 144 ± 25 pc (Stein 1991)


7 Complete the text:

Match up the trigonometric parallax phenomena with the image:
stellar parallax motion - A
Very Long Baseline Array - B
radio continuum - C
Chandra X-ray Observatory spatial resolution HRC-I ~ 0.5 arcsec - D
WD 0346+246 has a trigonometric parallax measurement - E
Very Large Telescope - F






8 Which of the following is not related directly to an astronomical trigonometric parallax associated with Geminga?

optical trigonometric parallax
the Fermi Gamma-ray Space Observatory
measurements of radio pulsars
only available for the nearby pulsars
distance value of 0.25 +0.12 or −0.06 kpc

9 True or False, For larger and trigonometrically less reliable distances, use the Wilson-Bappu magnitudes.


10 Which of the following is not an astronomical trigonometric parallax or derived from it?

Hipparcos mission (ESA 1997), π = 15.15 ± 3.24 mas
independent observational constraint for DA white dwarfs
parallax distance of 357 +43 or −35 pc
angular diameter comparison
distance estimates
the range of an artificial satellite

Hypotheses[edit | edit source]

  1. It is possible using X-ray trigonometric parallax to fix the position of the Sun.

See also[edit | edit source]

External links[edit | edit source]

{{Radiation astronomy resources}}