Shas­tri Boodan

There is al­ways some­thing ex­cit­ing and in­trigu­ing to look for in the night sky. Nev­er a dull night in­deed, con­tends Pro­fes­sor Shirin Haque, As­tronomer at the UWI.

Dr Haque said the lat­est ex­cite­ment in the world of As­tron­o­my has to do with a very in­ter­est­ing star near the con­stel­la­tion Coro­na Bo­re­alis. This star known as T Coro­n­ae Bo­re­alis (T CrB), al­so known as the Blaze Star, is a re­cur­rent no­va. This means that the star is go­ing to bright­en con­sid­er­ably for a short pe­ri­od of time of weeks and months be­fore it fades back to its for­mer dim self.

She said T CrB is ex­pect­ed to bright­en up every 80 years as as­tronomers pre­dict. T CrB was first dis­cov­ered in 1866 by Irish as­tronomer John Birm­ing­ham, and then its sub­se­quent bright­en­ing was no­ticed by a 15-year old boy, Michael Wood­man in 1946.

“There are, how­ev­er, pos­si­ble records of it be­ing seen as far back as 1217 and 1787. Michael Wood­man is now 94 and hopes to be the on­ly per­son to have seen this phe­nom­e­non twice.

“Ac­cord­ing to this cy­cle, a flare up is ex­pect­ed any­time now. The clock is tick­ing and there­fore sky­watch­ers should gaze up­wards to see if they can catch this rare phe­nom­e­non. It would on­ly bright­en up for a few days or so be­fore it be­gins to dim once again,” she said.

Dr Haque said the star has been show­ing the traits ex­pect­ed lead­ing up to the flar­ing, of slight dip in its bright­ness dur­ing the last decade, some­thing that it is ex­pect­ed to do be­fore it goes no­va.

“No­va” means new and it refers to stars that sud­den­ly ap­peared in the sky by an­cients who were un­aware of the phys­i­cal process­es hap­pen­ing.

She said this par­tic­u­lar sys­tem is part of a bi­na­ry sys­tem of a white dwarf and a red gi­ant star. The white dwarf has an in­tense grav­i­ta­tion­al field and it is suck­ing ma­te­r­i­al from its gi­ant com­pan­ion. How­ev­er, when a cer­tain thresh­old is reached, the dwarf star un­der­goes a ther­monu­clear ex­plo­sion caus­ing it to bright­en and ex­cite the in­hab­i­tants of plan­et Earth to see such a phe­nom­e­non.

The star sys­tem is about 3000 light years away and that means that we are see­ing the sys­tem as it ac­tu­al­ly was 3000 years ago, since it takes light that long to reach us.

So, the big ques­tion—can this be seen in T&T? Dr Haque said when the star is in its reg­u­lar phase, its mag­ni­tude is about 10. This means that it is on­ly vis­i­ble through a tele­scope. When the star goes no­va and bright­ens, it should be eas­i­ly vis­i­ble with the naked eye with a mag­ni­tude of about 2 (the larg­er the num­ber for the mag­ni­tude, the fainter the star).

How­ev­er, it should be not­ed that these process­es are very com­plex and do have a lev­el of un­cer­tain­ty about them. As it is, as­tronomers have been ex­pect­ing it to go no­va since some­time late last year. So, where and when can it be seen in the T&T skies?

The star will be in the north-east­ern sky from about 2 am un­til dawn ris­ing high­er as the night goes on. Two good point­er stars for those not too fa­mil­iar with the sky are Ve­ga and Arc­turus. Ve­ga will be the bright­est star in the sky in that di­rec­tion and Arc­turus the next bright­est star.

Draw­ing a straight line be­tween these two stars will be ap­prox­i­mate­ly where T CrB should be near the con­stel­la­tion Coro­na Bo­re­alis. It is a good idea to get fa­mil­iar with this re­gion of the sky and keep an eye on it—you nev­er know which night, sud­den­ly a star will ap­pear vis­i­ble to the naked eye that was not vis­i­ble be­fore to the naked eye.