Call for monitoring Be stars in the TESS sectors

Re: Call for monitoring Be stars in the TESS sectors

Postby Robin Leadbeater » Sun Aug 25, 2019 2:10 pm

Five high priority (7,8,9) targets from last night in poor variable cloud conditions compared with the latest spectra in BeSS. They are waiting for validation in BeSS but are available in the BAA database

(EDIT:- now in BeSS thanks Valerie !)


Robin

TESS_Be_20190824.png
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Re: Call for monitoring Be stars in the TESS sectors

Postby Robin Leadbeater » Mon Aug 26, 2019 8:44 pm

Last nights observations. Some interesting differences

HD175511 - He 6678 is present in absorption 20190322 but is absent currently. Does anyone know the astrophysical significance of this ?

V374 Cep - The only other spectrum in BeSS is a low resolution one from 2013. The intensity of emission is similar but profile looks suspiciously different. It is difficult to be sure with the difference in resolution though

V412 Cep - H alpha looks similar to the spectrum in BeSS taken 2 days earlier but there are some strange differences in the continuum on the red side of H alpha and the 6678 He absorption line has shifted to the blue and possibly changed shape. Are these differences real ?

Cheers
Robin

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Re: Call for monitoring Be stars in the TESS sectors

Postby Christian Buil » Tue Aug 27, 2019 5:26 pm

Two Be stars in the field of TESS not actually on BeSS database for the moments:

Image

Image

The spectrograph used is UVEX (600 l/mm, 750 nm blazed version, see http://www.spectro-aras.com/forum/viewtopic.php?f=45&t=2386).

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Re: Call for monitoring Be stars in the TESS sectors

Postby J Labadie Bartz » Tue Aug 27, 2019 11:43 pm

Hi everyone,

Wow! Truly excellent to see these observations so far! These will be quite valuable (even necessary, in my opinion) in properly interpreting the TESS data for these stars. Seeing these first few datasets for the stars in the TESS observing list is especially important in deciding observational strategies going forward because they tell us critical information like whether or not there is a disk, its relative strength, inclination angle, whether or not there is variability, etc. I will try to keep this post as short as possible- my goal with this post is to comment on the observations in this thread, which I am using to update the TESS observing spreadsheet.

Please let me know if there is anything I can do to improve the spreadsheet or any questions about scientific priorities (and especially any disagreements with my interpretations of these data). In the next few days I will post more details about the observing strategies that I think will be most scientifically valuable in the context of this community and additional resources (along with some TESS light curves and other data as examples). I am still working on updating the spreadsheet to incorporate these recent observations.

I'm excited to work with you all and am confident that these observations will be important given that TESS is probably the best opportunity to study large numbers of bright Be stars with photometry from space, and that simultaneous spectra are very important in interpreting the photometric signals of these systems given how variable disks can be.


Addressing some comments:

"Very true. TESS has been observing the southern hemisphere for the past year and will observe the northern hemisphere for the next year
https://tess.mit.edu/science/observations
Not sure what plans there are for TESS beyond 2 years"
Especially these first 3 sectors of TESS (13,14,15) are very northern. The remaining 9 will still be northern, but will extend further south. about the future plans of TESS: Neither is anyone else! It is not known what the plans for TESS are beyond the next 10 months.

"I guess more northerly (or last year southerly) targets may also have the advantage of being observed by TESS for longer due to the increased overlap of segments near the poles."
Yes, these stars observed in multiple sectors are better to observe because of the 2x+ TESS data. It will be easier to identify pulsation and outburst/flicker variability in the photometry, which of course spectra will help with immensely in interpreting this variability.


Notes for observations in this thread so far:

BD+27_3970 = TIC 126756648
Observed in Halpha by Robin night of 2019/08/20. 2.5xContinuum, W-shape profile with small delta-Vp. FWHM = 6.7A. Observed by Christian Buil 2019/08/25 showing apparently single-peaked Halpha at 2.5xContinuum. Medium/low priority of 4 now because the Halpha line suggests this is nearly pole-on and the disk is relatively strong for a B6/8 star, and it will be difficult to detect spec. changes.

EM* MWC 1030/TYC 3178-815-1 = TIC 296771641
Observed in Halpha by Robin night of 2019/08/20. 27xContinuum! Single peaked Halpha. EW = -110A, FWHM 3.3A. unidentified emission line at ~6515A. There is a low resolution spectrum from 20180716 which also shows H alpha in emission at similar EW. Expired as classical Be star based on Halpha profile and SED that peaks in the NIR.

HD_194779 = TIC 15126043
- Spectra so far do not show signs of Halpha activity. Still interesting to monitor no more than once per night. If Halpha activity is seen then higher cadence will be requested.

V568_Cyg = TIC 100165164
- Observed by Robin on 2019/08/24 and Olivier on 2019/08/07. Both show the ~same single-peaked 4.5xContinuum Halpha. Priority slightly lowered since we are unlikely to see much activity in the remaining time TESS is observing this star (until Sept. 11) given the high strength of Halpha and near pole-on orientation.

V1362_Cyg = TIC 40478523
- Nice observations by Robin on 2019/08/24 and James Foster on 2018/09/20 that show double-peaked Halpha with large changes in V/R over just 5 days. Similar variability is seen in NRES spectra from Jon Bartz. Continue to monitor at 1+ observation per night. Jon will continue to monitor with NRES. This clearly has interesting Halpha variability on short timescales and is likely to be variable in TESS.

V2113_Cyg = TIC 202752748
- Observed by Robin on 2019/08/24 and Olivier Thizy on 2019/08/02. Both show similar strength 4-4.5xContinuum Halpha with mostly single-peaked shape. Some structure apparent in Olivier's spectrum. Priority level remains at 7. Despite the strong Halpha, we might be able to see variability near the line center on short timescales if this is in fact a binary.

V2162_Cyg = TIC 240258004
- Interesting behavior in many observables (too tedious to name them all). High priority. Possible SB2. Very likely to be active on short timescales with TESS. Likely has a dense inner disk.

HD_175511 = TIC 236785664
Robin: "HD175511 - He 6678 is present in absorption 20190322 but is absent currently. Does anyone know the astrophysical significance of this ?"
Interesting observation + question. From Halpha, this is practically a shell star. My first guess is that an enhanced density in the inner disk could obscure the photosphere to a degree that would make the apparent depth of He lines smaller. But this would also presumably make the Halpha line core deeper, which we do not see in the observation. Non-radial pulsation can change the depth/shape of photospheric lines, but I don't think the effect would be so strong as to wash the line out completely. Or, maybe the photospheric Teff is variable. I don't have a good answer for this, but it's definitely interesting.
- This is one of the 3 Be stars that is being observed in 10+ sectors with TESS. Continued monitoring at a low cadence of 1 spectrum per week or so is ideal for now.

V374_Cep = EM* AS 505 = TIC 434972921
- Apparently a Herbig Ae/Be star according to Simbad. The SED peaks in the NIR and there seems to be dust excess. Probably not interesting for Classical Be star work, but this could still be interesting if its visible TESS light curve is variable (which would not be surprising).

V421_Cep = TIC 314576961
Robin: "H alpha looks similar to the spectrum in BeSS taken 2 days earlier but there are some strange differences in the continuum on the red side of H alpha and the 6678 He absorption line has shifted to the blue and possibly changed shape. Are these differences real ?"
- Interesting find! The He variability looks real to my eye. This could be consistent with pulsation changing the line profile shape. This is certainly worth continued monitoring especially since it will be visible for TESS sectors 15,16,17.

HD_175863 = TIC 233613741
- Observed by Robin and ChK on 2019/08/26 and 2019/08/22 respectively. No obvious difference in Halpha- pure absorption down to 0.72xContinuum. This star is in the TESS continuous viewing zone. In that respect, I think it is good there is no disk right now. Continue to monitor once every few days. If any change in Halpha, we want higher cadence observations. Good chance to observe a disk build-up from a purely photospheric level in both TESS and spectroscopy.

HD_183339 = TIC 284563819
Observed by Robin and Houpert 2019/08/26, 2019/03/20. narrow Halpha absorption with no variability. I don't think this is a classical Be star. Priority is lowered. Still, since it is in the TESS continuous viewing zone, a spectra every few weeks might still prove interesting.

HD_203356 = TIC 63318608
- Robin, 2019/08/25, and Charbonnel 2019/07/10 both see double-peaked weak Halpha in a wide absorption profile. No change between the two spectra. Based on the late spectral type and consistent line profile I doubt we'll see much variability over TESS timescales.

V2153_Cyg = TIC 373819241
- Robin, 2019/08/25, and vdesnoux 2019/08/08 both see ~4.5xContinuum mostly single-peaked Halpha. Some variation present. Halpha profile is somewhat distorted. Obviously not a shell star from the spectrum. Could be a binary based on observables. Will be interesting to continue to monitor. Nice target.

V420_Cep = TIC 313986452
Robin, 2019/08/25, vdesnoux 2018/07/14 both see single-peaked Halpha at 2.4xContinuum. Since older spectra from BeSS show up to 6xContinuum, we are probably seeing the disk at a relatively low state. Continued monitoring at low cadence is a good strategy since this is in 3 TESS sectors and we may see some disk growth from flickers.

BD+50_3188 = TIC 364925342
Christian Buil, 2019/08/25, apparently single-peaked Halpha at 2xContinuum. Not known in BeSS. APOGEE spectrum show Br11 double-peaked 1.2xContinuum with variable central depression. Priority lowered since the KELT light curve is exceptionally flat for a Be star. Still, one more spectrum couldn't hurt to see if there is variability in hydrogen lines.
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Re: Call for monitoring Be stars in the TESS sectors

Postby Joan Guarro Flo » Wed Aug 28, 2019 9:18 am

Hello Jonathan,

I don't know if you know that I and possible other observers we've left our observations for TESS program in BeSS Database.

In my case I've left in it V2113 Cyg, Hip101648, HD193182, HD175863, HD175511, HD183339, HD204116 and HD201036, this last still in webmaster because it isn't referencied in BeSS.

All of them by echelle spectrograph have resolution about 9000 with dinamyc range between 4052/7752 or 3977/9007 Angstroms.
.
Why can you study them, where do you think I have too to send them ?

Coming soon I going to send those observations to BAA DB too.

Regards, Joan.
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Re: Call for monitoring Be stars in the TESS sectors

Postby J Labadie Bartz » Wed Aug 28, 2019 2:08 pm

Hello Joan,

Thank you for pointing this out. I can see now that you and others have posted your recent observations of some of the TESS stars in BeSS already.

Now I am trying to think of a good way to keep track of new observations. The BeSS uploads are nice because of the automatic plots and ability to easily download data. But I think there is no easy way to see a list of the most recent spectra that have been uploaded and it will take too much time to search for each star individually to check if there are new observations.

Does anyone know of a way to keep track of new observations that match to the TESS spreadsheet list?

One possible idea:
For each observation of a target in the TESS spreadsheet, the observer can leave a brief comment in a column on the spreadsheet called "observed", like
"Jon Aug. 23, 25, 27
Joan Aug. 24, 25
...repeat for other observers"

I'm open to other ideas, but the above would be relatively easy and then everyone who uses the spreadsheet can quickly see the observing history of each star, and I can more easily check BeSS for new observations.
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Re: Call for monitoring Be stars in the TESS sectors

Postby Robin Leadbeater » Wed Aug 28, 2019 4:16 pm

Hi Jon,

I have added my observations to the "observed" column in the table (observation date followed by my initals eg 20190824_856 RL) If everyone adds their observations in date order, the latest date first, I think we should be able to see the last observation date easily

Cheers
Robin
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Re: Call for monitoring Be stars in the TESS sectors

Postby Joan Guarro Flo » Wed Aug 28, 2019 5:55 pm

Hello all,

I have followed Robin's procedure and I added my targets in TESS file, they ending in JG.

Regards, Joan.
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Re: Call for monitoring Be stars in the TESS sectors

Postby Olivier Thizy » Wed Aug 28, 2019 7:12 pm

Hello,


I am one of BeSS validator and we are almost up to date in our validation process. BeSS validated spectra are visible on the next day (around 01h00 UT).

As a Be star observer (and actually only observing Be stars with my backyard setup), I have added the priority >1 TESS target in my target list with increased priority (I am using an automated script which "select" targets based on telescope location, BeSS priority and my own "bonus" weight) and I have already observed/uploaded some of them in BeSS.

Here is my "TESS target" list: HD 205551 V2136 Cyg V421 Cep V2148 Cyg V568 Cyg V2163 Cyg V2113 Cyg HD 205060 HD 192445 V2120 Cyg V2153 Cyg


On top of those, I am actively observing and ask others to do so as well the star V442 And as there will be an intensive observing campaign this Fall (and it will be observed with TESS as well). This is one in coordination with PI Noël Richardson.


Anyway, to monitor a list of target in BeSS, you can use the VO ability of BeSS database. For exemple in VisualSpec it's easy to have a list of targets and check what are the latest spectra and display all of them:

Capture.JPG
Capture.JPG (113.23 KiB) Viewed 1021 times


Capture2.JPG



An alternative would be to look at BeSS robot file and extract from that list only the TESS target you are interested in; you have the date of the last obervation for each target. This robot file is modified every night from BeSS data sent to ARASBeAm:
URL: http://www.arasbeam.fr/robot/ObsC2AFull.txt

It would be easier than having to go to GoogleSheet every time. And it will put pressure on validators to validate spectra quicker in BeSS... :-)


I hope this helps...

Cordialement,
Olivier
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Re: Call for monitoring Be stars in the TESS sectors

Postby Olivier Thizy » Wed Aug 28, 2019 7:52 pm

PS: note that we manually validate ALL spectra in BeSS database. There is currently an average of 11 spectra submitted every day (114 if you count all echelle spectra orders)... :-)

As Valérie mentionned, there is a FaceBook private group for Be star observers (just need to be on facebook, have at least one spectrum validated in BeSS, and connect with me on facebook for me to invite you in the group). This is where we try to publish the targets we are acquiring to avoid two spectra of the same target at the same time.

Cordialement,
Olivier
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