[Fwd: Re: TT Ari spectrum]

From: Joe Patterson <*jop_at_astro.columbia.edu*> Date: Tue, 24 Nov 2009 05:54:56 -0500 · jop_at_astro.columbia.edu

Here's the spectrum that Ondrej Pecha took last night at the 2.4 m, 
which plainly shows the TiO absorptions characteristic of the M dwarf 
secondary.  At last beheld by human eyes.  I have a report from Marco 
Silva that the star entered an active state at 4:00 UT, so probably the 
experiment to compare the front and back sides of the heated secondary 
will have failed.  But it's wonderful to see the M dwarf features 
staring back at us!

We might try this experiment one more time on Nov 25 UT (Tues night in 
the USA), which will conclude this long campaign of 
photometry-spectroscopy-UV-X-ray.  That too will depend on notification 
of "low state"; so those notices late in the European night, and early 
in the USA night, will be crucial.  Thanks!

joe

-------- Original Message --------
Subject: Re: TT Ari spectrum
Date: Mon, 23 Nov 2009 22:39:06 -0700
From: Ondrej Pejcha <ondrej.pejcha@gmail.com>
To: Joe Patterson <jop@astro.columbia.edu>
References: 
<3bdbaaf40911191510j1ebe9d8bydbc81f1e27d368c2@mail.gmail.com>	 
<4B05E835.2020902@astro.columbia.edu>	 
<4B0A525F.1050905@astro.columbia.edu>	 
<3bdbaaf40911230126u3e8a2fdne631b9c9d4ac235d@mail.gmail.com>	 
<4B0A6293.9040700@astro.columbia.edu>	 
<3bdbaaf40911230224g216fb899n69dfb4991ca3b5b0@mail.gmail.com>	 
<4B0B3E32.6000601@astro.columbia.edu>	 
<3bdbaaf40911231929o3bb8725eg5061e23547288eb2@mail.gmail.com>	 
<4B0B6D1B.3070003@astro.columbia.edu>

Hello,

here's one of today's spectrum - it's flux calibrated. I will get
another one in about 40 minutes to see if there are any changes.

Best regards,

Ondrej

2009/11/23 Joe Patterson <jop@astro.columbia.edu>:
> Super!
>
>
> Ondrej Pejcha wrote:
>>
>> Hi Joe,
>>
>>> I have a preliminary report (waiting for confirmation) that TT Ari is at
>>> quiescence now.  It definitely was last night, by the way.  That first
>>> spectrum that you took a few days earlier - didja get that flux
>>> calibrated?
>>
>> The spectra I took on Nov 18 are not yet flux calibrated, but I took
>> standard star observations so it's possible to calibrate them (I
>> didn't know how to do that at that time). I also have 5400-6900
>> spectrum from that day, which I didn't send.
>>
>>> The ideal experiment now is to look for variable TiO features, which are
>>> mainly in the 7000-8000 A range.  So that might require a change of
>>> grating
>>> or tilt, depending on what you have in there - and likely would require
>>> an
>>> order-blocking filter, since the CCD has sensitivity at 4000 A.  All of
>>> that
>>> might be too much overhead; but if it isn't, fire away! Low res is fine,
>>> and
>>> I'm sure you'll see the TiO features.  Seeing 'em change with orbital
>>> phase
>>> is more optimistic, but a decent bet.  I estimate the temperature
>>> difference
>>> between heated and unheated faces of the secondary to be at least 1000 K.
>>
>> I will obtain 6500-9700 spectrum of TT Ari in about 40 minutes. I've
>> already taken observations of standard star and found that
>> order-blocking filter is really necessary. Good to discover that still
>> during the nights.
>>
>> Best regards,
>>
>> Ondrej
>>
>>> BTW, I just got the confirmation.  It's at quiescence now.  I'll send any
>>> report of its brightening (which cancels the experiment).
>>>
>>> joe
>>>
>>>
>>
>
>