Call for monitoring Be stars in the TESS sectors

Re: Call for monitoring Be stars in the TESS sectors

Postby JJ Broussat » Tue Oct 01, 2019 9:27 am

Hello,
Here is my participation taken during the last night with a Lhires III, 2400 l/mm, 23µ
R= 10480
RSB = 116

spectrum was sent to Bess.

hd212044.png
hd212044.png (5.96 KiB) Viewed 1318 times
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Re: Call for monitoring Be stars in the TESS sectors

Postby J Labadie Bartz » Fri Oct 04, 2019 9:00 pm

Hi everyone,

Good news! TESS sectors 14 and 15 are now available, and I am beginning to incorporate your data into the analysis of a few systems. This will take some time since there are a lot of stars with different properties. I'm starting with HD_194779, which transitions from disk-less, to posessing a weak disk that dissipates over a few weeks. This disk even was captured nicely in spectroscopy (Halpha mainly) and overlaps nicely with the TESS observations.

Maybe it is easier to view via this link rather than the image in this post:
https://drive.google.com/open?id=11PQnW ... 6nuHjjirxw

The plot here has a lot of info, which I break down below. From top to bottom, the panels show...
1) The frequency spectrum (power vs. frequency [cycles per day]) from TESS.
2) A wavelet analysis of the TESS data. This shows how the significant frequencies change over time.
3) TESS light curve. Vertical colored lines mark epochs of spectroscopic observations.
4) Halpha equivalent width, plotted so that higher values = more emission.
5) Halpha peak separation.
6) V/R ratio of the Halpha peaks.
Then the rest are some choice lines from the spectra. The large Halpha plot has an offset that corresponds to the spacing in time betweeen observations, while the rest are simply all the spectra stacked with no offset.

Here is a summary of what all this is telling us. The TESS data (via the top two frequency plots) show a strong signal near 1.1 cycle per day. This signal is strongest near TESS_JD = 1720 (easy to see in the wavelet plot, and you can also see this by eye in the LC). This is probably the dominant pulsation mode, and is typical for Be stars. There is another significant frequency just below this, at about 1 c/d. The TESS light curve also shows other slower variation (at low frequencies). This is obvious by eye if you look at the LC, and you can also see these signals in the frequency spectrum (the power at low frequencies). Some time between the first and second spectrum the star starts to build a weak disk, seen in Halpha. This disk then dissipates over the next ~3-4 weeks. You can see this in the Halpha line profile, the peak separation, and the EW.

Is it noteworthy that the disk build-up corresponds to about when the pulsation signal is strongest? Maybe! This is the sort of question we can start to answer as the sample grows, and is only possible with these sort of simultaneous phot. + spec. monitoring efforts.

There are some things I need to improve. One is to take all quiescent spectra of this star to get a nice average Halpha profile in the disk-less state. Then better measurements can be made of this disk build-up episode. Also, I need to incorporate other spectra that are not yet posted on BeSS.

Also, I have begun to monitor V357_Lac with NRES a few times a night. Already it is obvious that there is variation even from one hour to the next. All of your observations over the past month have made it clear that this is an ideal target and give me confidence in dedicating 5 observations per night every night for the next month while TESS is still observing it (until Nov. 2).

TESS will soon switch from sector 16 to sector 17 (on Oct. 7), and I will update the spreadsheet soon. Keep up the good work!



HD_194779_diagnostic_plot_01.png



-Jon
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Re: Call for monitoring Be stars in the TESS sectors

Postby James Foster » Fri Oct 04, 2019 10:06 pm

Here is my spectra as an animation for V0357 Lac (Ha-He6678A) from 01-04Oct2019:

Image
(Note: I used the H2O reduction function under the Profile tab in Isis 5.9.3 for each night's spectrum)

My average R=14000 for 3-3.5 hours of spectra exposing (12-14x900sec exp). I'll do this a day or so more before have
to swap out the spectroscope for maintenance/LISA IR observations.

James
James Foster
Lhires III (2400/1800/600 ln/mm Grat) Spectroscope,
LISA IR/Visual Spectroscope (IR Configured Presently)
Alpy 600 with Guide/Calibration modules and Photometric slit
Star Analyzer 200
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Re: Call for monitoring Be stars in the TESS sectors

Postby Christian Buil » Thu Oct 10, 2019 5:09 pm

Two recent high resolution Ha spectra of V357 Lac (VHIRES-MO spectrograph, R = 38 000 + Newton 0.25 m):

Image

(telluric lines removed on ISIS)

A spectrum of V442 And (active the October 8.9) by using the same setup :

Image

Christian Buil
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Re: Call for monitoring Be stars in the TESS sectors

Postby Christian Buil » Sat Oct 12, 2019 10:45 am

Add of a high resolution (VHIRES-MO, R= 38 000) of V357 Lac for the date 10.8/10/2019:

Image

Also a new spectrum of V442 And (10.9/10/2019):

Image

Christian Buil
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Re: Call for monitoring Be stars in the TESS sectors

Postby J Labadie Bartz » Sun Oct 13, 2019 6:16 pm

Hi all,

Continuing to see interesting variability in V357 Lac. The first spectrum here is on the night of Oct. 4.

He_I_6678_01.png


Fe_II_5169_03.png


smoothed_b_H-alpha_01.png
smoothed_b_H-alpha_01.png (74.99 KiB) Viewed 1064 times




Also working on V442 and, where the first spectrum is on the night of Oct. 9.

H-alpha_V442_and_01.png
H-alpha_V442_and_01.png (92.24 KiB) Viewed 1064 times


smoothed_b_H-beta_01.png
smoothed_b_H-beta_01.png (74.37 KiB) Viewed 1064 times
J Labadie Bartz
 
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Re: Call for monitoring Be stars in the TESS sectors

Postby J Labadie Bartz » Tue Oct 22, 2019 4:06 pm

Hi everyone,

I've had bad luck lately and haven't been able to get as much data from the NRES spectrographs as I had hoped lately, mostly due to telescope hardware problems. Still, I expect the combination of the NRES and all of your spectra will still provide an excellent dataset for V357 Lac. This remains a high priority target until Nov. 02 and I will continue to observe it as much as possible.

The next high priority Be star to observe along with TESS is V818_Cas (V ~ 7.8). This is being observed now in sector 17, and also in sector 18, until Nov. 27. Like V357 Lac, this star is very active in photometry and seems to eject mass often, and the more spectra the better. In the spreadsheet, there are almost 40 Be stars in both sectors 17+18 that are good to monitor at a lower cadence.

Another quite interesting star in sectors 17+18 is BD+61_39. This shows regular outbursts in photometry with a period of ~90 days.
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Re: Call for monitoring Be stars in the TESS sectors

Postby Olivier Thizy » Sun Oct 27, 2019 2:46 pm

Hello,


here is an update on V442 And outburst which started between sep 30th and october 5th. Emission is still growing:

20191027 Graphe V442 And.JPG


20191027 Graphes V442 And.JPG



Discovery spectrum on my blog:
https://observatoire-belle-etoile.blogs ... burst.html


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

Postby J Labadie Bartz » Thu Oct 31, 2019 12:29 am

Olivier,

I just want to say that's a really awesome dataset you're showing there. Very cool seeing the Halpha evolution, and even better that this happened at the same time as TESS observations. Unfortunately I wasn't able to contribute much to this, but especially since there was no pre-existing disk the Halpha data says quite a lot on its own.
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Re: Call for monitoring Be stars in the TESS sectors

Postby Olivier Thizy » Sun Nov 03, 2019 7:54 am

Updated graphs for V442 And using several spectra from BeSS (thanks to all observers!).

V442and-graphs.JPG



Same in 3D with colored spectrogram:

V442and-color3Dgraph1.JPG



Using the first spectrum as baeline (ie: substrated) to only show the emission line:

V442and-color3Dgraph.JPG



Cordialement,
Olivier
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