Notre Dame Student's Study of "Lost Star" Draws Attention to Hidden Costs of War

Author: Peter Garnavich


Notre Dame Sophomore Katherine Hill led a study of the magnetic cataclysmic binary star YY Draconis (YY Dra). The study used observations of NASA's Transiting Exoplanet Sky Survey (TESS) satellite to better understand the matter transferred from the binary's cool companion to a compact white dwarf with a strong magnetic field. The TESS satellite caught the binary as it fell into a deep faint state implying that mass transfer came to a halt for just over one day before recovering. The paper has been accepted for publication in the Astronomical Journal and has been posted to the astrophysics preprint archive (

Hill's paper motivated a review by Taichi Kato and Elena Pavlenko ( of the identity of YY Dra and its possible confusion with a star named DO Dra. Kato and Pavlenko point out that the variable star YY Dra was discovered by the Ukrainian-born astronomer V. Tsesevich in 1934 after analyzing a series of photographic glass "plates". Unfortunately, the position of the star measured by Tsesevich appears to have been inaccurate. Fifty years later, a satellite identified a source of X-rays from a variable star that was then named DO Dra, the star studied by Hill and her co-authors. A long controversy has raged over whether YY Dra is the same star as DO Dra, or if it is a truly lost variable star.

Kato and Pavlenko note that the uncertainty surrounding YY Dra could have been resolved by simply re-analyzing the photographic plates used by Tsesevich from his original discovery. But these plates were destroyed during World War II, so that it may be impossible to ever recover the true nature of the lost star YY Dra.

In an unusual conclusion to an astrophysics paper, Kato and Pavlenko note: "At the time of writing of this paper, crises are unfolding in Ukraine. As we have seen, the final conclusion on Tsesevich’s YY Dra is almost impossible to reach due to the result of World War II. The same thing also happened in various fields of science … We wish that no further destruction of our treasures should occur.”

The Notre Dame co-authors of the variable star study, Hill, Colin Littlefield, and Peter Garnavich agree, stating that "As Russia continues its barbaric invasion of Ukraine, the loss of the star named YY Dra appears insignificant, but it is a reminder that war not only kills people, it destroys everyone's shared cultural and scientific heritage."

As part of their conclusion, Kato included an illustration of a Ukrainian dove for Peace designed by Natasha Alimova as an expression of solidarity with the people of Ukraine during a period of civil unrest in 2014.