# Trigonometric-parallax astronomy/Quiz

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.

Trigonometric-parallax astronomy is a lecture and an article about the using higher resolution detectors to measure stellar parallaxes. It is also a lecture as a possible part of the department of astronomy course on the principles of radiation astronomy.

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## Quiz

1

True or False, Distance measurement by parallax is a special case of the principle of triangulation.

 TRUE FALSE

2

Trigonometric parallax involves which of the following?

 parsecs reciprocal of parallax arcseconds 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

 displacements.

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 VLBA - C 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.

 TRUE FALSE

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

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