28 Tau ARAS monitoring

James Foster
Posts: 439
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Re: 28 Tau ARAS monitoring

Post by James Foster »

To: Olivier,

Its mostly because Procyon very bright and well situated in a good part (end) of night. Before I do an IR curve, I take out H2O lines in Ha.

RE:".....you can take for exemple Gam Aur (a B7III)"
Do you mean Beta Tau? Got confused because according to Wikipedia Gam Aur was recently named Beta Tau; see:
https://en.wikipedia.org/wiki/Beta_Tauri

I'll try to use this star next time...........


James
James Foster
eShel2-Zwo ASI6200MM Pro
Lhires III (2400/1800/600 ln/mm Grat) Spectroscope
LISA IR/Visual Spectroscope (IR Configured)
Alpy 200/600 with Guide/Calibration modules and Photometric slit
Star Analyzer 200
Olivier GARDE
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Location: Rhône Alpes FRANCE
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Re: 28 Tau ARAS monitoring

Post by Olivier GARDE »

Yes you're right, Gam Aur and Bet Tau is the same star :
http://simbad.u-strasbg.fr/simbad/sim-i ... =submit+id

I think it's better to take this kind of star for instrumental response (better to match the continuum).

You spectra are welcome in bess data base and you can upload here (both H beta and H Alpha)
http://basebe.obspm.fr/basebe/
LHIRES III #5, LISA, e-Shel, C14, RC400 Astrosib, AP1600
http://o.garde.free.fr/astro/Spectro1/Bienvenue.html
Ernst Pollmann
Posts: 461
Joined: Mon Sep 26, 2011 7:16 pm

Re: 28 Tau ARAS monitoring

Post by Ernst Pollmann »

James,
would you be so friendly to send me your Halpha spectra for monitoring of RV, V/R and EW ?

Ernst
Ernst Pollmann
Posts: 461
Joined: Mon Sep 26, 2011 7:16 pm

Re: 28 Tau ARAS monitoring

Post by Ernst Pollmann »

Dear colleagues,
it seems that the next periastron passage of 28 Tau is coming somewhat earlier than the ephemerides says.
Normaly we should to expect it around February 18th (this year), but current spectra of Alun Halsey and Joan Guarro are showing a quick change of radial velocity as indicator for that event (see attachment).
28tau_RV.png
It would be great, if further observers could dedicate to this event too.
Ernst Pollmann
Olivier GARDE
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Location: Rhône Alpes FRANCE
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Re: 28 Tau ARAS monitoring

Post by Olivier GARDE »

It seems to have a reversal in the intensity of the V/R peaks in fifteen days.
Image
LHIRES III #5, LISA, e-Shel, C14, RC400 Astrosib, AP1600
http://o.garde.free.fr/astro/Spectro1/Bienvenue.html
Ernst Pollmann
Posts: 461
Joined: Mon Sep 26, 2011 7:16 pm

Re: 28 Tau ARAS monitoring

Post by Ernst Pollmann »

... yes, Olivier, this could be an indicator for the periastron passage.
Question is, has this already taken place or not?
Further observations will be required urgently!!

Ernst
Ernst Pollmann
Posts: 461
Joined: Mon Sep 26, 2011 7:16 pm

Re: 28 Tau ARAS monitoring

Post by Ernst Pollmann »

Congratulation Alun Halsey & Olivier Garde !
Obviously you was able to catch the last "very sharp" periastron passage of 28 Tau with the V/R ratio and radial velocity in your spectra.
A really great result which enables to calculate the next periastron passage now with new precisely time reference.
28tau_VtoR.png
28tau_RV1.png
28tau_RV2.png
Ernst Pollmann
Ernst Pollmann
Posts: 461
Joined: Mon Sep 26, 2011 7:16 pm

Re: 28 Tau ARAS monitoring

Post by Ernst Pollmann »

Dear colleagues,
during an observation period of about 6 years, we always observed in the community a synchronous variation of the V/R ratio with the radial velocity RV. Within this period, 10 periastron passages have occurred with an orbital period of 218 days (Nemravova et al., A & A, 2010), of which we can document 6 passages with our observations.
28tau.jpg
28tau.jpg (90.46 KiB) Viewed 38491 times
The observed V/R variation correspond to a deformation of the central absorption core as it also to see in Fig. 6 of Nemravova et al. 2010. This systematic V/R variation during each minimum of radial velocity might confirm new aspects of the structure of the growing disk. Is striking that the V/R period is somewhat smaller (approx. 2 days).
The next periastron passage will take place at the beginning of September this year and should be observable.
Ernst Pollmann
James Foster
Posts: 439
Joined: Sun Jan 24, 2016 7:14 am

Re: 28 Tau ARAS monitoring

Post by James Foster »

I was able to squeeze in spectra observations of 28 Tau (Plenione) in CaK, Hb, & Ha bands with the LhiresIII with 2400 l/mm grating:
CaK:
Image
Hb:
Image
Ha:
Image

I don't see any obvious changes from spectra taken 1 month ago (orbital velocities increasing?)....but I haven't been following this object that long in high resolution.
Ernst (Took these 28 Tau spectra from your request in Spectro-L Yahoo)...let me know if you need the BeSS formatted spectra of these emailed......

James
James Foster
eShel2-Zwo ASI6200MM Pro
Lhires III (2400/1800/600 ln/mm Grat) Spectroscope
LISA IR/Visual Spectroscope (IR Configured)
Alpy 200/600 with Guide/Calibration modules and Photometric slit
Star Analyzer 200
Ernst Pollmann
Posts: 461
Joined: Mon Sep 26, 2011 7:16 pm

Re: 28 Tau ARAS monitoring

Post by Ernst Pollmann »

James,
yes, please send my your spectrum for evaluation.

Ernst
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