The first questions ask about the exoplanet 51 Peg b, discovered in 1995. In the Exoplanet Archive, one can find the data measured for Marcy et al. (1997) in the Ancillary Information section.
One can download the ASCII data itself by clicking on the left-hand icon, then use any plotting program to make a graph. Or, if one clicks on the right-hand icon, the Exoplanet Archive will make a graph using the data in the browser itself.
This graph shows that the amplitude of the variations in the radial velocity of the star is about +/- 60 m/s.
If one has downloaded the data, one can use any tool to search for periodicity. The Exoplanet Archive has a "Periodogram" tool which can do this work quickly.
This tool shows a strong peak at about P = 4.23 days.
If one plots the measurements folded with this period, one sees a clean sine-like curve:
The next questions refer to the exoplanet around a different star, called 51 Eri.
HW 2: Based on Macintosh et al. (2015), approximately what was the angular separation between host star and exoplanet in the discovery images?
As seen in Fig 1, above, the planet is about 0.5 arcseconds (or 500 mas) from the host star.
HW 3: De Rosa et al. (2015) attempt to compute an orbit for this exoplanet around 51 Eri. The result is not very good because they had positions of the object at only ______ different times. (Fill in the blank)
As seen in Table 1, above, there are just five measurements.