Betelgeuse

Re: Betelgeuse

Postby Robin Leadbeater » Sat Jan 11, 2020 1:18 am

No change at all in the last 10 days in the visible at (low R~130) resolution. (yes there really are two spectra plotted there :) ) The latest one was with the ALPY200 which I happened to have on the scope. Not ideal for this sort of brightness. It saturated in 0.3sec so I had to average ~50 exposures to beat the scintillation :lol:

betelgeuse_20191230-20200110_R130_Leadbeater.png
betelgeuse_20191230-20200110_R130_Leadbeater.png (22.78 KiB) Viewed 2169 times
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
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Re: Betelgeuse

Postby James Foster » Sun Jan 12, 2020 5:40 pm

I decided to switch out the LISA-IR spectroscope with the LhiresIII and take a quick spectrum of Betelgeuse last night with the 2400 l/mm grating with 35micron slit. Seeing wasn't very good.
I needed a 25 second exposure at 2x2 binning with the CDK17 telescope to get the continuum up to about 25K adu per sub-exposure. I took 15 exposures and discarded the 5 worst and
processed as usual in Isis5.9.3. Based on the telluric H2O line at 6516.5A, I shifted the spectrum by -0.3A to align to this feature. I saved the .fits file, then re-opened it Bass Project V 1.9.8.
I then added another H-Alpha spectrum of Betelgeuse I took over a year ago (09Jan19) and compared them as shown:
Image

Note that the 09Jan19 spectrum was shot with my 13" with slightly longer exposures of 30 seconds per sub exposure; adu values per exposure were about 40k.
I normalized both spectrum and Y-scaled the earlier (09Jan19-2nd) to the latter (12Jan20). It looks like the energy profile on the right-hand wing (right of HA) is lower in the present spectrum of
Betelgeuse. The resolution of my present (12Jan20) is inferior to the earlier (09Jan19); R=10230, vs R=14737. Besides these, not much else different.

James
James Foster
eShel2 (under development-1/3)
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: Betelgeuse

Postby Benjamin Mauclaire » Mon Jan 13, 2020 4:33 pm

Hi James,

Comparing line's strength/intensity from spectra with different resolution leads to a wrong diagnostic.
The more the resolution power RP is high, deeper line are.
However, quantities such as EW are do not depend on RP.

As Francois initial post didn't mention any observation advices nor PI for studying Betelgeuse behaviour, we don't know which wavelength bandwidth nor RP and what to look at. This is pretty suprising that so many spectral observations have been done without any specific goal.

Cheers,

Benji
Spcaudace spectroscopy software: saving you hundred hours of frustration.
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Re: Betelgeuse

Postby James Foster » Fri Jan 17, 2020 9:05 pm

To: Benjamin,

RE:"Comparing line's strength/intensity from spectra with different resolution leads to a wrong diagnostic.
The more the resolution power RP is high, deeper line are."

Quite right, I tweaked my condenser lens and got a bite higher resolution on my 13Jan2020 and compared:
Image

But to answer what you correctly quoted Francois on the more important feature to study, the Effective line width (EW) in this case Ha, I cropped
these between 6558.4A and 6568.9A and produced a chart that makes measuring the EW a little easier:
Image

I took this into PS and did my best to measure equal areas within the Ha region that comprise the EW; see:

Image

Trial#1, 09Jan19 for H-alpha EW= 3.09A / Trial#1, 13Jan20 for H-alpha EW= 3.08A
Trial#2, 09Jan19 for H-alpha EW= 2.94A / Trial#2, 13Jan20 for H-alpha EW= 2.95A

Diff: EW(09Jan19)-EW(13Jan20)= +0.01A Trial#1
Diff: EW(09Jan19)-EW(13Jan20)= -0.01A Trial#2

Average= 0.00A

Basically, these measurements say is there has been no noticeable change in over a year in a Orion's H-alpha EW at the resolution we can see with the LhiresIII.
Basically all I can say with these Telluric (not RV) calibrated H-alpha spectra of a Orion is that the 13Jan20 Ha line is shifted towards the UV with respect
to the 09Jan19 Ha line; note that these were not radial velocity corrected. Let me know if you have anything else helpful to add!

James
James Foster
eShel2 (under development-1/3)
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: Betelgeuse

Postby Benjamin Mauclaire » Sat Jan 18, 2020 9:51 am

Hi James,

You will find some informations about *** Equivalent *** width EW measurement andd how to do it with Spcaudace software [1]:
http://spcaudace.free.fr/docs/index.php?doclink=ew.html

Note that uncertainty computation is mandatory for every type of measurement in order to be able to compare with litterature values and to know how consistent the measurement is.
Here EW uncertainty is a bit overestimated but I will code a new algo based on recent paper.

Cheers,

Benji

[1]: http://spcaudace.free.fr
Spcaudace spectroscopy software: saving you hundred hours of frustration.
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Re: Betelgeuse

Postby James Foster » Sat Jan 18, 2020 2:38 pm

To: Benjamin,

Thanks for the Spcaudace software reference! I have to admit that I have used very little of the analytical tools in Isis, BaSSProject and/or Vspec.
I tried using this AudeLA before, but it was unable to interface it to my instruments and I ended-up using Isis and BassProject for my most of spectra processing.
I believe I was able to install and update to the most recent version of AudeLA (26/05/2018) and install the "SPECTRUM for SpcAudACE." When in Spcaudace, I was unable
to open up my BeSS formatted spectra profile .fits file without getting the following error:

load M:/SPECTRA2019/__Home13Jan20(-5)CDK17-LhiresIII2400Grat-35micronSLIT/ALL Processed Spectra_BeSS Check/_aoriha_20200113_272a-0.2A.fit
Libtt error #104: Detail=
load M:/SPECTRA2019/__Home13Jan20(-5)CDK17-LhiresIII2400Grat-35micronSLIT/ALL Processed Spectra_BeSS Check/_aoriha_20200113_272a-0.2A.fit
Libtt error #104: Detail=
while executing
"buf$audace(bufNo) load "$rep_et_filename""
(procedure "spc_loadfit" line 68)
invoked from within
"spc_loadfit"
(menu invoke)

I'll try using Vspec to get the EW for my 09Jan19 and 13Jan20 a Orion spectra. Btw, the diagrams on your link: "http://spcaudace.free.fr/docs/index.php?doclink=ew.html"
were most helpful!

Sincerely Yours,

James
James Foster
eShel2 (under development-1/3)
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
James Foster
 
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Re: Betelgeuse

Postby Benjamin Mauclaire » Sat Jan 18, 2020 3:21 pm

Hi James,

Your path (directories where fits file are stored) and files name must not contain characteres such as space, accents, etc.
This is described here: http://spcaudace.free.fr/installation.php#conseils
This directory's name has to be corrected: "ALL Processed Spectra_BeSS Check".

After what it will work fine.
Some tips:
- Have allways Audela's Console window visible to be able to whatch error messages and type commands.
- First of all, setup the "working directory" using Setup menu of Spcaudace.

Benji
Spcaudace spectroscopy software: saving you hundred hours of frustration.
Benjamin Mauclaire
 
Posts: 234
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Re: Betelgeuse

Postby James Foster » Sat Jan 18, 2020 5:14 pm

To: Benjamin,

Thanks for the tips! I'll try this again latter, but I used Vspec (which has no problem opening my Isis generated/BeSS formatted files without renaming) to get the following:

20190109_340_james r. foster-0.22aheliocorr.fit
Trial #1
barycentre: 1454.5394
moyenne: 0.697
ecart type: 0.335
snr: 2.083
FWMH: 1.524
centre: 6563.3965
leq: 1.32
intensité: -24.5253
aire: 47.414
Trial #2
barycentre: 1451.6775
moyenne: 0.678
ecart type: 0.336
snr: 2.019
FWMH: 1.506
centre: 6563.2321
leq: 1.265
intensité: -22.7689
aire: 43.404


20200113_272a-0.2aheliocorr.fit
Trial #1
barycentre: 1336.5547
moyenne: 0.939
ecart type: 0.408
snr: 2.301
FWMH: 1.372
centre: 6563.0796
leq: 1.063
intensité: -25.0491
aire: 55.404
Trial #2
barycentre: 1335.1499
moyenne: 0.925
ecart type: 0.409
snr: 2.265
FWMH: 1.383
centre: 6562.9988
leq: 1.081
intensité: -25.7406
aire: 52.752

EXAMPLE SCREEN SHOT OF VSPEC
Image

So the Average EW (leq in Vspec) for my 09Jan19 data is (1.32+1.265)/2= 1.2925A with an average intensity of -23.6471‬ and average area 45.409
The Average EW for me 13Jan20 data is (1.063+1.081)/2=1.072A with an average intensity of -25.39485 and an average area of 54.078.

So there is a EW difference of about 1.29 vs 1.07 between the 09Jan19 and 13Jan20 data around the H-Alpha absorption feature. Thanks for the great references!

James
James Foster
eShel2 (under development-1/3)
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
James Foster
 
Posts: 390
Joined: Sun Jan 24, 2016 7:14 am

Re: Betelgeuse

Postby Benjamin Mauclaire » Sat Jan 18, 2020 5:38 pm

Integration's limits for EW compuation have to be the wavelength were line cross the local continuum.
That's why Spcaudce computes a continuum for EW computation.
This continuum has a important influence in EW value.

Benji
Spcaudace spectroscopy software: saving you hundred hours of frustration.
Benjamin Mauclaire
 
Posts: 234
Joined: Thu Sep 29, 2011 10:14 am

Re: Betelgeuse

Postby James Foster » Sun Jan 19, 2020 6:11 am

To: Benjamin,

RE:"Integration's limits for EW compuation have to be the wavelength were line cross the local continuum."

I totally agree, it took me many tries in Vspec to find a suitable place in a Ori's chaotic continuum for normalization.
I will try out Spcaudce's powerful features on these spectra to better educate myself and get higher accuracy on the EW
characterization. Again thanks for all the pointers!

James
James Foster
eShel2 (under development-1/3)
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
James Foster
 
Posts: 390
Joined: Sun Jan 24, 2016 7:14 am

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