Call for observations of the preoutburst phase of T CrB

[Rainer Ehlert]

Hi,

Had a more or less clear night and here another T CrB spectrum.

https://rainerehlert.com/000_Spectra/T_ ... 16b_1D.fit

[Robin Leadbeater]

Peter, Robin, thank you for your interesting inputs.


HD143894 is A3V with V = 4.82 with no mention of variability so is likely to be the better choice for low resolution use. You will need to use a Pickles A3V spectrum for this. This is available with ISIS.

Perhaps someone with reliable photometric skies (not mine!) can measure this star relative to standards eg CALSPEC to confirm its spectrum relative to the Pickles spectrum ?

Cheers
Robin

[Rainer Ehlert]

Hi Francois,

I can not send you e-mails. I get answered that your e-mail does not exist. francoismathieu.teyssier at gmail dot com ...

Please contact me at

eastpier at rsfotografia dot com

Thank you and regards Rainer

[Rainer Ehlert]

Hi,

Another T CrB spectrum addition and so I have four now.

https://rainerehlert.com/000_Spectra/T_ ... _16_1D.fit

[Dubreuil Pierre]

T Crb hier soir, proche IR

UVEX4 G600-750nm, slit 15µ

Spectre T_CrB 6339 to 8299.png (128.02 KiB) Viewed 6198 times

Pas vraiment d'évolution pour l'instant.

Pierre

[Rainer Ehlert]

Hi,

Yesterday night eg. today morning UTC time I imaged T CrB. See below the comparison of 5 spectra from 26-07 to 10-08 and I ahve the impression teh emission lines 4640 and 4684 are stronger or is it just my imagination ?

Thanks for looking

[Francois Teyssier]

Hi Rainer,

Interesting.
But the height of a line is a very poor measure as it depends significantly of the resolution at that wavelength.
The measure of the equivalent width (EW) will provide more accurate measures.
I suggest using plot spectra (Tim Lester), a very nice tool.
http://spectro-aras.com/forum/viewtopic.php?f=51&t=2820
Keep us informed!

And , as the level of the continuum is almost the same between H beta and He II, the ratio of the EW HeII/Hb provides useful information about the temperature of the hot source.

François

[Rainer Ehlert]

Hi Rainer,

Interesting.
But the height of a line is a very poor measure as it depends significantly of the resolution at that wavelength.
The measure of the equivalent width (EW) will provide more accurate measures.
I suggest using plot spectra (Tim Lester), a very nice tool.
http://spectro-aras.com/forum/viewtopic.php?f=51&t=2820
Keep us informed!

And , as the level of the continuum is almost the same between H beta and He II, the ratio of the EW HeII/Hb provides useful information about the temperature of the hot source.

François

Hi Francois,

Thanks and I downloaded it yesterday and now I just need to understand the program and how to use it.

I was able to shoot another hour of T CrB yesterday night. Will see how it compares to August 10th

Rainer