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UXOR campaign page seriously updated

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pox
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UXOR campaign page seriously updated

The page especially for the UXOR campaign has now been updated following some great feedback at the Boston meeting. The 'old new' list of 41 (visual) stars has now increased to 115 objects (visual/CCD) with all coordinates given. Several of the EA stars have no determined periods at all, so at the very least if no UXORs are found, we may have provided data for these stars' periods! If you are not au fait with how to observe EA stars, please use the link to the EB section on the updated page. As charts become available for these stars, I will add a column to the DB which will be reflected in the page, so do keep returning for the latest updates.

 

MJB
MJB's picture
UXOR C.

when I go to the site or click on the link in you message above all I see is a small handful of stars and no coordiantes.  The message implies more stars and coordinates.  I have a student that might like to pursue some of these stars. If​ you have a better list please advise how I might obtain it.  Thanks. 

 

pox
pox's picture
updated list of uxors

Those 14 stars are the final list, whittled down from the original longer list. I haven't included the coordinates on this page because it is assumed that users will just go to VSP to find the chart/sequence. Sorry for the 'promises' in the original post!

mishnik
mishnik's picture
UXOR campaign

How correctly to make observations for these stars in order to distinguish them from the Algoles? I was very interested in this topic.
Thank you.

Sebastian Otero
Sebastian Otero's picture
Differences

Catching en eclipse will in some cases be enough to at least classify them properly.
An EA-type eclipse will show a symmetry (clean and similar descending and ascending branches) that won't be present in an UXOR light curve.

Check VSX to see the last information on any star you observe (we constantly update information so it might be that some stars are already confirmed as EAs and have periods).
 

mishnik
mishnik's picture
Differences

When you observe enough filter V? Because the main indicator is the non-symmetry in eclipses.

Sebastian Otero
Sebastian Otero's picture
Colors

Multicolor data are always useful.
These stars have B-V bluer than J-K so determining B-V for those who lack it will be revealing.
Also the fact that at deep minimum they undergo a color reversal: they get redder as they fade but then start to get bluer again.

But the symmetry of the fadings will be one of the best indicators.

Cheers,
Sebastian

mishnik
mishnik's picture
Colors

It turns out that out of eclipses B-V is darker than J-K?

Sebastian Otero
Sebastian Otero's picture
B-V vs J-K

No, the opposite and that is one of the ways to find them. They show infrared excess and B-V is bluer than J-K.
To avoid confusion I wouldn't call the fading events "eclipses" although the star is dimmed by dust/gas clumps.

mishnik
mishnik's picture
B-V vs J-K

Once again I will ask, because a very important point. Outside of eclipses, the star is blue, and when it eclipses, it turns red? Do I understand correctly?

Sebastian Otero
Sebastian Otero's picture
Color behaviour

The star is not necessarily "blue", it is bluer in B-V than in J-K.
These are mostly B and A-type stars (Herbig AeBe stars) although the UXOR behaviour has been recently found in later types too.
There is some reddening in B and V too so you won't find UXORs with negative B-V even among the B-type stars.

And again, don't call them eclipses.
These stars get redder when they start fading but as the fading gets deeper this behaviour changes and they become bluer again. It would be interesting to see this in the data.

mishnik
mishnik's picture
Color behaviour

Thank you. I will try to discover these changes.

 

mishnik
mishnik's picture
Color behaviour

- What does "infrared excess" mean? In what cases can infrared radiation be considered redundant?

- What processes are caused by blue during the low minimum?

Thank you.

 

pox
pox's picture
IR excess

All heat sources (including non-'red' stars) emit Infra-red, but usually in the case of stars, this IR is overwhelmed by the shorter-wavelength emission. The IR is still there, it is just 'swamped' by the rest of the radiation.

With many YSOs, the presence of the circumstellar dust/gas cloud - which is warm enough to emit IR but not, as a rule, visible light because of its comparatively low temperature - allows there to be comparatively more IR radiation than with main-sequence stars, and this is the IR excess.

hambsch
hambsch's picture
UXOR dense coverage

Hi,

is there interest in a denser coverage of those stars? I could cover the latter 7 from my remote observatory in snapshot mode. I could do B and V images.

Is there anybody interested in the results and will do the analysis/paper writing?

Josch

mishnik
mishnik's picture
UXOR dense coverage

I was interested in these stars and I began to observe them. Now I am accumulating material. In parallel, I develop a methodology for observations. If there is any data, it will be good.

 

hambsch
hambsch's picture
Ok will take up some stars

I have not yet started observations, but will take up some stars and send data to the AAVSO.

I will use a V filter to start with. If you are interested in more filtered data I could also use B and I filters.

Josch

mishnik
mishnik's picture
UXOR dense coverage

As I understand it is necessary to determine the beginning of the eclipse and then check the color indicator "B-V". But in the normal state, too, several observations are needed through the filter "B" for comparison.

Sebastian Otero
Sebastian Otero's picture
B and V

B and V would be useful to see the color reversal at minimum.
You can go multicolor as soon as you detect a fading (a couple of BV points at maximum would also be useful for comparison as Nikolay said).

hambsch
hambsch's picture
B and V

Ok, after I got my first images tonight to see the exposures in V I will add B exposures as well.

I am doing the stars in Sco and the one in Sct.

Josch

mishnik
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B and V

Good. Just this area of the sky is not accessible to me. I'm now testing Cyg, Cas and Lac.

 

pox
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In addition to what Sebastian

In addition to what Sebastian says about 'eclipses', another point to note is the lack of strict periodicity, and also behaviour outside of 'eclipse'.

hambsch
hambsch's picture
First points uploaded to AAVSO

HI,

 

first data points are uploaded to the AAVSO databse for the 4 stars.

More to come.

Josch

mishnik
mishnik's picture
First points uploaded to AAVSO

Can you write what?

 

hambsch
hambsch's picture
What do you mean?

I have uploaded V data on the three stars in Sco and the one in Sct. My initials are HMB. I have not had the time yet to add B filter to my observing program, which is very intense (Observing more than 45 stars nightly). Do you need more information?

Josch

mishnik
mishnik's picture
What do you mean?

Yes, if it is possible, which stars did you observe? And filter "B" is desirable to use together with "V". For example, "B-V-B-V". At least one observation is so to conduct, well, if you notice the darkening, it is surely in this order.

Nicholay.

hambsch
hambsch's picture
Based on the list ín the first contribution to this thread

I checked the website of the 14 remaining stars

Those are the ones I observe:

V0603 Sco
13.2
13.8
26.3
 

V0698 Sco
12.7
13.7
258
 

V0699 Sco
13.4
14.7
0
 

V0730 Sco
13.8
14.3
0
 

HI Sct
15.4
16
0

mishnik
mishnik's picture
Request OU Cas

Who has the opportunity to observe today in the interval between 19.30 and 21.00 (UT) OU Cas. We need a continuous photometric series of B-V-B-V.

mishnik
mishnik's picture
Result OU Cas

The "OU Cas" is of type EA.

 

hambsch
hambsch's picture
Some B-V data available

HI after nearly one month of daily snapshits the B-V of HI Sct is about 2, for V603 Sco about 1.3, for V698 Sco about 0.5, for V699 Sco about 1.2. V730 Sco I have not started yet. For V603 Sco I got already a minimum.

Josch

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