ARG00009go - radio active star?
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by JeanTate
The bright IR source slightly offset from the head of this #tadpole radio source is SDSS J143440.82+564554.6, a ~16 mag star of spectroscopic class K3, also a USNO object with zero pm.
Is it possible that the star is radio active?
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by akapinska scientist
Yes, stellar radio sources can be observed, perfect example would be for instance pulsars (neutron stars). But in general radio stars are fairly rare; well as compared to radio galaxies and AGN which dominate the radio maps at these frequencies and sensitivities! 😃
If you want to know more about physics then have a look at this lecture: http://www.annualreviews.org/doi/pdf/10.1146/annurev.astro.40.060401.093806
I'm not expert in stars so can't comment on this one, but I think I would expect rather compact emission from stars with the FIRST survey. Anyway, stellar experts from our team should jump in here 😃
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by JeanTate in response to akapinska's comment.
Thanks.
I know the Sun is radio active, especially when flares go off, and as it's a fairly normal G dwarf, I'd expect a good fraction of main sequence stars are similarly active. But the Sun's intrinsic radio brightness is, well, rather wimpy, right? If it were, what, a few dozen pc away, FIRST wouldn't see it, even if an X-class flare were aimed straight at it, right?
What I was wondering is whether a K3 star* with zero pm could possibly be the source of FIRSTJ143441.0+564603 ... the zero pm suggests that it's not close, so more likely a giant (or supergiant) than a main sequence star (I realize that it's far more likely that the radio source is a distant AGN plus jet/lobe, especially if the offset is real/the FIRST astrometry is ±~1")
*there's no doubt that the SDSS spectrum is of a K3 star!
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by JeanTate in response to akapinska's comment.
If you want to know more about physics then have a look at this lecture: http://www.annualreviews.org/doi/pdf/10.1146/annurev.astro.40.060401.093806
I've no doubt that document is well worth reading.
Unfortunately, it's not readily accessible:
Purchase access to this review article using a credit card or an Annual Reviews access token.
(Grants access for 24 hours after purchase - registration required)
Review Price: $32.00(USD)$32 just to be able to read it for only 24 hours ... well, it's surely not that good.
Many individuals can gain access to the full-text through their institution's site license. Before purchasing this article or a subscription, we encourage you to check your library's holdings.
OK, but I'm just an ordinary zooite; I have no 'institution' (I guess they mean university, right?), so there's nothing for me to check.
Now what?
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by akapinska scientist
It's archived here http://arxiv.org/abs/astro-ph/0206436 to get around the pay-wall.
I must have put the link from my office earlier where we have access to online journals 😉Besides, with regards to the radio emission from stars - completely forgotten to mention the obvious supernovae!
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by JeanTate in response to akapinska's comment.
Thanks.
Figure 1 seems to summarize the situation re normal stars (i.e. not pulsars or SNe). If I am reading it right, at least one K 'single star' supergiant has been observed (the red circle top middle), and quite a few K giants (though most are in 'RS CVn' or Algol binaries. Further, the K supergiant is among the most intrinsically luminous (log(L) ~18).
However, it seems that no observed (normal) radio star has a huge radio plume ...
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