@@ -2,8 +2,8 @@ Known Issues
22============
33
44As we discuss in the paper, **EVEREST ** has certain limitations, particularly when
5- it comes to saturated stars and stars in crowded apertures. Below we outline these
6- limitations with some examples.
5+ it comes to saturated stars, stars in crowded apertures, and very variable stars.
6+ Below we outline these limitations with some examples.
77
88.. contents ::
99 :local:
@@ -66,6 +66,24 @@ greater than 2 or 3. Other pipelines are likely to perform better for these targ
6666 Note that saturated and crowded stars were **not ** included \
6767 when computing the overall performance of **EVEREST ** relative to \
6868 other pipelines (such as in `Figures 10-15 <precision.html >`_ in our paper).
69+
70+ RR Lyrae and very variable stars
71+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72+
73+ .. figure :: 211069540_everest.jpeg
74+ :width: 600px
75+ :align: center
76+ :height: 100px
77+ :figclass: align-center
78+
79+ The :py:mod: `everest ` pipeline is also likely to fail for very short period
80+ variable stars, such as RR Lyrae stars. When the stellar variability signal is
81+ stronger and at a higher frequency than the instrumental signal,
82+ nearly all the de-trending power comes from the GP, and the resulting CDPP is rather
83+ insensitive to the value of the PLD coefficients, leading to poor de-trending. Imperfect
84+ optimization of the GP can also lead to damping of the stellar variability signal,
85+ which is evident in the light curve shown above. Consider using the
86+ `K2VARCAT catalog <https://archive.stsci.edu/prepds/k2varcat/ >`_ for these stars.
6987
7088Ultrashort-period EBs
7189~~~~~~~~~~~~~~~~~~~~~
@@ -81,7 +99,7 @@ eclipsing binaries. If the eclipses take up a significant fraction of the orbit,
8199not much continuum flux to train the model on. It's also likely that the eclipses
82100(particularly the secondaries) may not be properly identified as outliers, in which case
83101the GP optimization step will favor a kernel that captures the short timescale, high amplitude
84- variability introduced by these eclipses. When this happens , all the de-trending power
102+ variability introduced by these eclipses. As in the variable star case , all the de-trending power
85103comes from the GP, and the resulting CDPP is insensitive to the value of the PLD coefficients,
86104which as a result end up taking on effectively random values. This results in light curves
87105like the one above, where the eclipses get washed out and the white noise gets inflated
0 commit comments