Cosmic birthday: HE 1523-0901

I would like to make a confession.  I am beginning to feel some of the symptoms of age.  Not old age, so much.  Just age.  Exercise is becoming something I need to consciously undertake, no longer something that simply happens among all the stuff I do in the week.  Lifting my daughter is no longer as effortless as it was a year ago.  (Okay, so that’s more a sign of her age than mine.)  Sleep is becoming a welcome goal at the end of the day, instead of an unwelcome necessity getting in the way of things I’d rather be doing.

But I have the perfect way to avoid falling into worry about my aging:  I think about HE 1523-0901. Here’s a picture of her with a few of her sisters:

Let's call her "Nan"

Yes, HE 1523-0901 is a star.  But not just any star.  She is the oldest observed object in the Milky Way.  Astronomers have estimated her age at 13.2 billion years (though, being a lady, she’s not acknowledging the estimate).  On the Cosmic Calendar, that’s today, the 14th of January.  Happy birthday, HE 1523-0901!

Keep in mind, when considering her age (born only 500 million years after the Big Bang), that the Milky Way itself is not thought to have come together in the form we now know until (at the earliest) 10.1 billion years ago – by which time HE 1523-0901 was already over three billion years old.

She is a slim star, weighing in at (forgive me, my lady) about 0.8 times the mass of our own sun.  She is a red giant, and is found about 7500 light years away in the direction of Libra.  She is apparently difficult to find from as far north as I am, so I will have to content myself with images like the above one, taken by the professional paparazzi to the stars.

I invite you to look up more about this lovely Grand Dame of our galactic family.  It certainly helps me to put my aging worries in perspective.

Finally, a note to any astronomers reading this:  she needs a better name!  I vote we call her “Nan”, after my granny.  Before you think that this is a rather backhanded way to honour my maternal forbear, let me explain.  My granny is now … well, somewhat less than 13.2 billion years old, but old enough to have three great-grandchildren.  She can still out-walk folks my age when she goes hiking around the Essex countryside.  So, just as Granny doesn’t seem to let the years touch her, I propose we honour our long-lasting stellar neighbour.  May she live another 13.2 billion years!

Photo credit:

Photo of HE 1523-0901 (Nan) from the gallery of Anthony Ayiomamitis.  (Copyrighted but assuming fair use.  Go check out his collection of amazing and educational astronomical photos!)

Redundancy note:

I’ve mentioned HE 1523-0901 before, but that’s the beauty of birthdays:  you can celebrate them anew each year.


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