# Technetium stars **URL:** \ **Category:** Factual Questions\ **Created:** [March 16, 2001, 3:22am UTC](https://boards.straightdope.com/t/technetium-stars/58179 "2001-03-16T03:22:46Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [March 16, 2001, 3:22am UTC](https://boards.straightdope.com/t/technetium-stars/58179/1 "2001-03-16T03:22:46Z")
I’ve heard that there is a class of stars whose spectra show the presence of technetium- an unstable element not otherwise found in nature (except maybe for vanishingly small traces from the spontaneous fission of uranium). This would apparently mean that nuclear reactions are taking place on these stars surfaces instead of their cores. But none of the sites I could find mention them in any detail. Any good astrophysics sites on this subject? ---
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [March 16, 2001, 6:02am UTC](https://boards.straightdope.com/t/technetium-stars/58179/2 "2001-03-16T06:02:00Z")
Help me out here… Technetium is a transuranic element, right? What its atomic number…I don’t have access to a periodic table around here…DUH! the web! I’ll be right back… ---
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [March 16, 2001, 6:34am UTC](https://boards.straightdope.com/t/technetium-stars/58179/3 "2001-03-16T06:34:43Z")
Oddly enough, it’s NOT transuranic. Atomic number 43, even though it has no stable isotopes. [http://www.webelements.com](http://www.webelements.com) is a wonderful periodic table / elements resource. Nonetheless, their entry does no more than just mention its presence in the spectra of some stars: [http://www.webelements.com/webelements/elements/text/Tc/key.html](http://www.webelements.com/webelements/elements/text/Tc/key.html) ---
**Author:** ![AWB](https://avatars.discourse-cdn.com/v4/letter/a/bb73d2/32.png) [@AWB](https://boards.straightdope.com/u/AWB)\ **Post date:** [March 16, 2001, 12:03pm UTC](https://boards.straightdope.com/t/technetium-stars/58179/4 "2001-03-16T12:03:58Z")
Although it has no stable isotopes, [sup]97[/sup]Tc, [sup]98[/sup]Tc, and [sup]99[/sup]Tc have half-lives of 2.6-, 4.2-, and 21 million years. That amount of time might allow any Tc being made in the core time to well to the surface and emit its spectrum. I found this on the [Los Alamos Periodic Table](http://pearl1.lanl.gov/periodic/) site: > [@](#): > > \*Technetium has been found in the spectrum of S-, M-, and N-type stars, and its presence in stellar matter is leading to new theories of the production of heavy elements in the stars. \* The Bad Astronomer is a poster here. Maybe he has some info on Tc in stars. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [March 19, 2001, 1:54am UTC](https://boards.straightdope.com/t/technetium-stars/58179/5 "2001-03-19T01:54:02Z")
Bumped to top so Bad Astronomer will see it in recent posts.