Nereid

There has been considerable discussion in the literature about the rotation of Nereid and the amplitude of its light curve (Schaefer and Schaefer 1988a, Schaefer and Schaefer 1988b, Bus and Larson 1989, Williams, Jones and Taylor 1991, Thomas, Veverka and Helfenstein 1991, Dobrovolskis 1995, Buratti, Goguen and Mosher 1997). A summary of these papers is provided by Buratti, Goguen and Mosher 1997. While our R band images of Nereid only measure the light curve for 1 hour on each night, a large magnitude change would be strong evidence of a large amplitude () light curve similar to those reported by Schaefer and Schaefer (1988a, 1988b) and Williams, Jones and Taylor (1991).

The observations and data reduction are described in the previous section. Each R band image was used (rather than the combined images) so any rapid changes of the magnitude of Nereid could be easily detected. SExtractor (Bertin and Arnouts 1996) was used to obtain the photometry of Nereid and this photometry is summarised in Table 2.

Table 2 shows that the magnitude of Nereid does not significantly change on either night of observation. A magnitude increase is seen between the two nights but the error estimate for this magnitude change does not include systematic errors which may have varied between the two nights of observations. It should also be noted that Nereid is in a busy field during the observations and this could introduce a bias into the magnitude estimates. Our measured lightcurve for Nereid is consistent with observations by Thomas, Veverka and Helfenstein (1991) and Buratti, Goguen and Mosher (1997) who also found no large variations of Nereid's magnitude. Our R band magnitudes are also similar to those reported by Buratti, Goguen and Mosher (1997). We can not rule out a large amplitude light curve for Nereid, however, our observations are consistent with Nereid having a light curve with .

UT Date	UT time	R band magnitude
		and error
30 Sep 1997	9:40
30 Sep 1997	9:52
30 Sep 1997	10:04
30 Sep 1997	10:16
30 Sep 1997	10:28
30 Sep 1997	10:40
30 Sep 1997	10:52
30 Sep 1997	Average
1 Oct 1997	10:03
1 Oct 1997	10:14
1 Oct 1997	10:40
1 Oct 1997	10:52
1 Oct 1997	11:04
1 Oct 1997	Average

 

© Copyright Astronomical Society of Australia 1997