New UXOR variable discovered by one of our observers

American Association of Variable Star Observers (AAVSO)
Tue, 07/21/2015 - 01:16

One of the highlights of the week in VSX was the discovery of a bright large amplitude UXOR variable by AAVSO observer Bruce McMath (JBMC).

Bruce was observing the 10th mag. T Tau star GW Ori (which usually barely varies) when he found that the 111 comp star in GW Ori's sequence might have some variability beyond the uncertainty.
He contacted the Sequence Team and after checking survey data we found that he was right.

The new variable turned out to be more interesting than its neighbours (it is also 73" away from the T Tauri star V0649 Ori which only varies by 0.5 mag.). It had been more or less quiet at maximum between 1999 and 2005 (V= 10.7-10.8) but in that year started to show deep fadings typical of UXOR variables.
A spectral type Fe had been published in 1970 so that confirmed the classification.
The star is in the lambda Orionis star forming region so it is not really a surprise to find it is variable (the surprise in this area of the sky is actually finding constant stars!), the interesting thing is that it had remained undiscovered even when both the ASAS-3 and CRTS survey clearly detected its variability.

The star is BD+11 820 and it already has its VSX entry with a combined light curve.

This is a good example of how there is still plenty of room for discoveries even in the surveys era. And how observing one star may lead to find another which might potentially be even more interesting.