AAVSO Bulletin 81 for 2018 - Stars with Double Maxima

In AAVSO Bulletin 81 there are two stars that exhibit double maxima:  R Cen and R Nor. These stars therefore have primary and secondary maxima and minima. They are not included in the main Bulletin table. Their predicted dates of maximum and minimum for January 2018 through February 2019 are presented here in list form (JD and Gregorian calendar dates) and in approximation of the main Bulletin table format.

V Boo, a semiregular, has intermittently demonstrated double maxima behavior for a number of years. In 2014 it became too irregular to predict maxima and minima accurately and was omitted from AAVSO Bulletin 78. However, in 2015 V Boo became more regular and was not demonstrating double-maxima behavior, so it was returned to the non-double-maxima stars. Observations of V Boo are strongly encouraged, and with an approximate magnitude range of 7-11, it is accessible to many sizes of binoculars and telescopes.

In the information below, 'I' indicates a primary extremum and 'II' a secondary. For example, MAX(I) in the list and MAX(13-I) in the table both mean a primary maximum, in this case on the 13th of the month in which the date appears. Dates are for 2018 except where indicated 2019.

R CEN   P = 512 days   
2458241 MAY 2 min(I)
2458373 SEP 11 MAX(II)
2458494 JAN 10, 2019 (minII)
no MAX(I) in 2018

R NOR   P =  507.5 days
2458132 JAN 13 MAX(I)
2458209 MAR 31 min(I)
2458299 JUN 29 MAX(II)
2458507 JAN 23, 2019 min(II)
 

In the table below, the following fields are given:
Name: name of variable star
Links:
 L - to the AAVSO Light Curve Generator
 X - to the International Variable Star Index (VSX)
 T - to the AAVSO table of published maxima/minima of long period variables
R.A. and Declination: coordinates in J2000.0
Period: in days
Range: average visual magnitude range based on data in the AAVSO International Database
N: number of observations in the AAVSO International Database received during calendar year 2017
JAN-DEC-FEB: January-December 2018, January-February 2019

The number in a given month indicates the date of extremum; MAX indicates Maximum and 
min indicates minimum.  The colors indicate (as chosen by the user) the intervals when 
the star will be brighter than visual magnitude 11.0 or fainter than magnitude 13.5.

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