[AAVSO-DIS] How to find new Mira variables without really trying.

Thu Nov 3 13:42:59 EST 2005

Wherein databases are searched, lightcurves assessed, cross indexing is undertaken, and three previously completely unknown Mira 
variables are presented.

First of all, access the CDS VizieR webservice http://vizier.u-strasbg.fr/viz-bin/VizieR

In the topmost input box type UCAC2 and then press the FIND CATALOGUE button

At the next page click on the I/289/out button

Choose maximum entries of 9999 to ensure no truncation, as nowhere near this number will be found

Set OUTPUT LAYOUT to preference of choice

In the TARGET BOX type in the following somewhat arbitrary sexagesimal J2000 coordinates (these are in hour, minute, seconds of ra 
followed by degrees arcmins and arcsecs of declination) :-

10 00 00 -40 00 00 

A TARGET RADIUS of 10 degrees can then be chosen in the dialogue to the right of this, that being the maximal permissible under this 
system

Click the box under POSITION and click the circle under that, so J2000 sexagesimal position will be output, the output being sorted 
thereon

In the SHOW column of the main table click on only UCMAG, JMAG and KMAG

Actually, any choice will do, but you may especially want to use these later

NOW, magnitude decisions:

UCAC2 mag is somewhat imprecise, but usually within range of Johnson V.  Although it is unfiltered red, it is not that distant from 
V, as it overlaps V and Rc bands in its range.

The lightcurves are going to be checked using ASAS3 which is only adequate to about V = 12.5 or so in most cases, also the ASAS3 
group themselves have hunted within their own dataset for new variables so it is wisest to look at the fainter end of the data, 
sufficient to be bright enough to avoid too much scatter, yet faint enough to hope they have missed some variables due to sensibly 
cautious search criteria on their part

Consequently, in the input box next to UCMAG enter the following exactly as shown

12..13

this means, in VizieR-speak, all mags from 12 to 13 inclusive

It is the case that red long period variables occupy specific regions within redmag-J and J-Ks plots.  There's overlap with other 
types at the boundary, and some very minor spread of the red variables out of this realm, but on the whole demarcations can be made

VizieR's interface does not readily lend itself to arithmetic assessment, however

Nevertheless, any object of red-J > 6 and J-Ks > 1.2 is certainly a red star

So, in the input box next to JMAG enter exactly the following

0..6

This means any Jmag between 0 and 6

A further entry of 1.2..3 could be placed in the KMAG box if desired, however this is redundant.  Any star with red-J > 6 will have 
J-Ks > 1 or so, anyway.

The above inputs will ensure that all matches have red-J of at least 6 or larger

Press the SUBMIT QUERY BUTTON

Your results will output a list of nineteen objects similar to this :

Full    _RAJ2000      _DEJ2000    UCmag   Jmag    Kmag 
          "h:m:s"       "d:m:s"     mag     mag     mag 

    1  09 10 47.372  -40 37 41.00  12.88   5.071   3.453
    2  09 10 58.188  -42 40 58.80  12.64   5.467   3.792
...
   19  10 22 41.358  -47 40 07.43  12.92   5.906   4.570

Now, to check the ASAS3 lightcurves for these 19 candidates

The above coordinates can be converted into ASAS3 coordinates (hhmmss-ddmm.m , that's decimal arcminutes for declination), probably 
most quickly by hand, and inserted into urls for automatic invocation of the ASAS3 lightcurves

Cut and paste the following text between the -------- lines into a simple text editor and save the file as newmira.html .  Avoid 
wordwrap, each line ends in <br>

------------------------------
<html>
<base href=http://www.astrouw.edu.pl/>
09 10 47.372 -40 37 41.00<img src=/cgi-asas/asas_plot_raw_all?091047-4037.7,asas3,0,900,0></a><br>
09 10 58.188 -42 40 58.80<img src=/cgi-asas/asas_plot_raw_all?091058-4241.0,asas3,0,900,0></a><br>
09 14 50.051 -45 02 49.37<img src=/cgi-asas/asas_plot_raw_all?091450-4502.8,asas3,0,900,0></a><br>
09 18 46.994 -35 44 18.30<img src=/cgi-asas/asas_plot_raw_all?091847-3544.3,asas3,0,900,0></a><br>
09 21 13.925 -46 52 24.09<img src=/cgi-asas/asas_plot_raw_all?092114-4652.6,asas3,0,900,0></a><br>
09 22 16.308 -42 38 50.68<img src=/cgi-asas/asas_plot_raw_all?092216-4238.8,asas3,0,900,0></a><br>
09 31 23.824 -37 19 59.10<img src=/cgi-asas/asas_plot_raw_all?093124-3720.0,asas3,0,900,0></a><br>
09 31 49.285 -32 26 32.52<img src=/cgi-asas/asas_plot_raw_all?093149-3226.5,asas3,0,900,0></a><br>
09 34 41.338 -47 09 34.80<img src=/cgi-asas/asas_plot_raw_all?093441-4709.6,asas3,0,900,0></a><br>
09 34 44.476 -42 25 24.85<img src=/cgi-asas/asas_plot_raw_all?093444-4225.4,asas3,0,900,0></a><br>
09 38 02.275 -45 23 39.50<img src=/cgi-asas/asas_plot_raw_all?093802-4523.7,asas3,0,900,0></a><br>
09 39 57.860 -47 55 40.50<img src=/cgi-asas/asas_plot_raw_all?093958-4755.7,asas3,0,900,0></a><br>
09 40 38.865 -41 05 42.04<img src=/cgi-asas/asas_plot_raw_all?094039-4105.7,asas3,0,900,0></a><br>
09 50 56.127 -49 48 07.63<img src=/cgi-asas/asas_plot_raw_all?095056-4948.1,asas3,0,900,0></a><br>
09 52 49.706 -46 03 17.80<img src=/cgi-asas/asas_plot_raw_all?095250-4603.3,asas3,0,900,0></a><br>
09 57 01.547 -35 57 41.15<img src=/cgi-asas/asas_plot_raw_all?095702-3557.7,asas3,0,900,0></a><br>
09 57 16.379 -48 35 29.75<img src=/cgi-asas/asas_plot_raw_all?095716-4835.5,asas3,0,900,0></a><br>
10 17 10.578 -46 10 46.13<img src=/cgi-asas/asas_plot_raw_all?101711-4610.8,asas3,0,900,0></a><br>
10 22 41.358 -47 40 07.43<img src=/cgi-asas/asas_plot_raw_all?102241-4740.1,asas3,0,900,0></a><br>
-------------------------------

Load this file into an internet browser, pressing reload if necessary, though it should work automatically

A line containing the RA and Dec followed by a lightcurve will be presented for each object

IMPORTANT POINT :- these objects now have to be checked for knownness!!!

Not only will some already be known Miras within the General Catalogue of Variable stars (and this is indeed the case, guess which 
from the lightcurves), but even more will be objects detected by the ASAS3 team themselves (this too is the case), yet there will 
also be previously unknown variables there (and this too is also the further case)

Some of the ASAS3 objects will be lamely classified as MISC, whereas they will self evidently be Mira or SemiRegular variables to 
anyone who cares to look

AND some of the 19 will not have been detected by the ASAS3 team at all, and therefore previously entirely unsuspected of variability

I use various routes for cross matching against known variables, primarily via Guide 8 and multitudinous hooked in catalogues, 
whereas other people use differing methodologies.  In time VSX may well allow such checks to be made.

In so doing I find the following :-

The 2nd, 8th and 14th objects in the list (if I count properly) are brand new Mira that are previously unknown to not only the GCVS 
and ASAS3, but also unknown by a plethora or other variability surveys, and also each with just about enough data to have a good stab  
at estimating their periods.

Let's call 'em John's new Mira 1 to 3, shall we?  The periods seem to be about 350, 350 and maybe 400 days, though the last one is a 
bit complex maxima wise

There may be other previously unknown variables in the list, I've concentrated on the Mira type variability, even though all seem 
evidently variable. 

The position chosen to search upon was somewhat arbitrary, any position covered by UCAC2 and ASAS3 could have been used.  The red-J 
criterion could be lessened to 4 or 5, and the UCMAG made brighter, although these cases will lead to nonvariables and known 
variables being an increasingly larger proportion of the objects returned in the list

Note that these three previously unknown objects tend towards being sparsely sampled Mira whose maxima only occasionally peak above 
the lower magnitude threshold limit of the ASAS3 system

And there it is, 3 new previously unknown Mira variables in less time than it took to write this up, create an email account and 
subscribe to aavso discussion.

John Greaves