T Coronae Borealis Finder Chart.pdf
Coronae Borealis (CrB) All Sky Charts for
1-April, 1-May, 1-June, 1 July, 1-Aug, 1-Sep
It is a very rare thing to be able to predict an exploding star, but astronomers are doing just that. When Tycho Brahe observed a naked-eye star where none had been there before, in 1572, he called it “nova,” because he thought he was seeing the birth of a new star. In fact, he was observing the death of a star.
Today we broadly characterize exploding stars as a nova or supernova. A supernova can be 4 billion times the luminosity of the Sun for a few weeks. A nova can achieve a luminosity of hundreds of thousands of Suns for a few days. While not as bright, a nova can repeat the same trick many times whereas a supernova is a one-time event. A typical time interval between explosions is normally many thousands of years. However, there are a very few stars that are known to erupt on a timescale more friendly to humans. T Coronae Borealis is one of those stars.
After erupting in 1866, It returned to its normal brightness. On February 10, 1946, the star appeared more than 600 times brighter than it did the week before. Analysis of the brightness of T Corona Borealis shows that the year before the explosion, the star dims. T CrB began its dimming phase in March, 2023. When T CrB does go nova, it is expected to be easily seen with the naked eye, even from large cities. It probably will not remain bright enough to see without a telescope for more than a few days.
This will be the most watched star in the sky for the next few months, with the possible exception of the Sun. Will you be the first to see it?
Currently At The Observatory
April 14, 2024 through May 1, 2024
A Note of Explanation Regarding Astronomical Magnitudes and Colors
MacAdam Observatory was able to complete two sets of data for T CrB, on Saturday and Sunday nights. We used the Blue (B), Green (V), Red (R) and Infrared (I) filters. The two figures show the magnitudes in the B, V and I filters, and the color index (B-V) and (V-I) for both nights.
The first three observations we found; B = 11.48, V = 10.25 and I = 7.55 with no significant changes between the three observations. The color index values for the first three nights were (B-V) = 1.24 and (V-I) = 2.74, again with no change between the three nights.
Since then we have three more observations, and it appears that T CrB is brightening in the B and V magnitudes. You can see the brightening in the current figures. The last three observations found B = 11.27, V = 10.10 and I = 7.49. This can also be seen in the color figure where (B-V) = 1.17 and (V-I) = 2.61.
When B and V magnitudes increase but I does not, it suggests the temperature is increasing. The (B-V) and (V-I) are color indices. When they go down in value, the system is becoming more blue. This can happen when the temperature begins to rise (hotter objects are more blue; cooler objects are more red).
We know that the magnitude and color changes as the giant star and white dwarf orbit each other. This could be the effect that we are currently seeing. MacAdam Observatory will continue to monitor T CrB and share updates.
March 28, 2024
Current researches by Dr. Ron Wilhelm include observing a type of variable star known as RR-Lyrae stars, named for the prototype star, the variable labeled RR in the constellation of Lyra. This star in the constellation Lynx is about 100 times too faint to be seen without a telescope. The star is pulsating, in and out with a period of about 6 hours wherein it becomes 45 % brighter than its minimum.
Light curve of the variable star, TV Lynx (a.k.a TV Lyn). The blue data points show the rapid increase in brightness for TV Lyn, compared to stable reference stars (other colors). Tonight, we observed the compression hump (near UTC = 0.67 days) and the maximum light (near UTC = 0.7 days). The compression hump is due to extra light being emitted because of collisions between infalling outer layers and outward moving, inner layers. We are studying this star to search for changes in the pulsation period, the time it takes to finish one pulsation cycle (~ 0.24 days).
