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Betelgeuse

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stellakafka
stellakafka's picture
Betelgeuse

Friends,

Surely, you have noticed that Betelgeuse is fainting. Although this is not unusual for this irregular star, this seems to be a deeper "dip" than in previous years. Spectra are strongly encouraged, all resolutions and all wavelength ranges, as we try to follow the phenomenon with all means possible...

Thank you in advance for your consideration!

Best wishes - clear skies,

Stella.

astrodamian
astrodamian's picture
Betelgeuse

laugh laugh

weo
weo's picture
alf Ori (Betelgeuse) observing campaign - Alert Notice 690

AAVSO Alert Notice 690 requests photometry and spectroscopy of alpha Ori (alf Ori, Betelgeuse) during and beyond its current minimum. Please see the notice for details and observing instructions.

Many thanks, and Good observing,

Elizabeth O. Waagen, AAVSO HQ

Robin Leadbeater
Subtle spectrum changes

Based on low resolution spectra (ALPY600 R~520) the change in the visible spectrum appears to be quite subtle (equivalent to a change in spectral class from M2 to M3.5 say based on the increase in TiO absorption band depth, much in line with Atel#13365) 

https://britastro.org/comment/7649#comment-7649

Also nothing obvious in high resolution R~11000 echelle spectra

http://www.spectro-aras.com/forum/viewtopic.php?f=38&t=2433#p13512

Spectra available from the BAA database

IR band measurements where most of the flux is could be interesting.

Robin Leadbeater
Betelgeuse in the IR

I see there is now a recent H,J point in the AAVSO database (The first for over a year)

It shows that Betelgeuse is not fading in the IR where most of the flux is so I would venture to suggest there has not been any significant drop in bolometric luminosity, just a small drop in temperature which has produced an exaggerated effect at V mag, a region sensitive to changes in the depth of the molecular absorption bands.

Cheers

Robin

File upload: 
Robin Leadbeater
No change in past 10 days

I grabbed another spectrum last night using the ALPY200 faint object spectrograph (Not the best target for this instument but that was the setup I was using at the time. It saturated in just 0.3 sec so I had to average about 50 exposures beat down the scintillation ! )  There has been no change in the visible region at low (R~130) resolution over the past 10 days. (Yes there really are two spectra in the graphic, they overlay almost exactly)  Spectra in the BAA database.

Cheers

Robin

stellakafka
stellakafka's picture
nice spectrum

Hello Robin,

 

Thanks for taking the data. I would appreciate it if you could also upload them to the AAVSO spectroscopic database, as this is where data are being retrieved by the professional astronomers who are interested in the star, and would be gret if they would use your spectra too.

I am attaching a screenshot of the latest light curve. Betelgeuse seems to be dimming more ... maybe?

 

Please keep observing!

Best wishes - clear skies,

Stella.

 

Robin Leadbeater
Databases

Hi Stella,

All my spectra are uploaded to the BAA database as it started up before  the AAVSO database and is also accessible by professionals and amateurs. Perhaps you could point interested parties there

https://britastro.org/specdb/

I would prefer not duplicating the uploading of data. Perhaps the AAVSO could mirror the BAA data as is done for the  variable star data ?  Since both conform to the BeSS standard perhaps this should not be too difficult ?

Cheers

Robin

stellakafka
stellakafka's picture
up to you!

Hello Robin,

We are not taking data from the BAA database to include in ours, as they ar enot validated. Indeed, it wouldn't be diffucult if we all had the same standards...

 

Best wishes - clear skies,

Stella.

Robin Leadbeater
Validation

Hi Stella,

The BAA moderate new observers and mentor to achieve good quality and then trust observers to produce good quality data. This is the same as BAA and AAVSO do with variable star photometry/visual brightness data for decades. As far as I can see there is no published specification for spectra to "pass"   the AAVSO standard (SNR, wavelength calibration accuracy, artifacts?) so it is not obvious what validation actually means. I dont understand why AAVSO have decided to take a different approach with spectra.

Cheers

Robin

Robin Leadbeater
Recent low resolution spectrum evolution

See here 

https://www.aavso.org/comment/68176#comment-68176

(Too many threads on the same subject !)

stellakafka
stellakafka's picture
policies on new databases

Hello Robin,

 

This is part of out new internal policies we have on new databases - same with exoplanet: validate every single data point that is being submitted (in line with BESS). Advertised when the databases opened. Photometry is a little mroe complicated b/c of long history...

 

I am certainly open to relevant discussions with the BAA leadership, but this is not the point of this forum conversation...

 

Best wishes - clear skies,

Stella.

FJQ
FJQ's picture
Here is my Betelgeuse spectra

Here is my Betelgeuse spectra from 22 & 24 January 2020, shot with the Alpy600(22Jan20) and the LISA-IR(24Jan20):

 

 

All identified spectral lines are tentative. (These were uploaded as Visual and IR spectra to the AASVO spectra database).

James

ACN
ACN's picture
Photography of Bellatrix x Betelgeuse (2020/01/25)

Friends,

Photo by L.A.R. Araujo (no. 2590)  (2020/01/25/02/46)

I   separated the 2 images (Bellat and Betelg )  of the same photo (2590) and put them side by side on  a  program (Frontpage)...for I can compare the images of 2 stars.

It seems me that  here  Bellatrix is  more brilliant than Betelgeuse!

This is the combined  image!.

Carlos (ACN)

 

Robin Leadbeater
continuing evolution of Betelgeuse spectrum

The low resolution spectrum has continued to evolve further since 2020-01-18, following the same trend noticeable in the red around 7400A (The spectra are in relative flux, scaled  to 1 in the V passband)

 

Robin Leadbeater
H alpha evolution

I was alerted by James Foster on the ARAS forum to possible changes in  the strength of the H alpha absorption line.  Comparing my medium resolution ( R~5500 )  spectra for this region for 2019-12-28 and 2020-02-04, there has indeed been a reduction in the line strength between the two dates.

Cheers

Robin

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