Betelgeuse

Re: Betelgeuse

Postby James Foster » Tue Feb 04, 2020 10:43 pm

To: Paolo,

RE:"Hi Robin, here's the comparison...."
Can you upload your divided spectrum to BAA so Robin or anybody else can compare directly? His divided Alpha Orion spectrum referenced here:
http://www.spectro-aras.com/forum/viewtopic.php?f=38&t=2433#p13514 has been placed in BAA as well so you can download; you can get
my Alpha Orion spectra from there as well....Cheers!

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
James Foster
 
Posts: 384
Joined: Sun Jan 24, 2016 7:14 am

Re: Betelgeuse

Postby Paolo Berardi » Wed Feb 05, 2020 5:04 pm

Hi James, nice spectra! I uploaded the original Alpha Ori profiles (six spectral intervals) on BAA database. You find in attachment the Miles division FITS profile I showed in my previous post.

Paolo
Attachments
alf_ori_20200123_8_div_miles_hd39801.zip
(25.5 KiB) Downloaded 88 times
Paolo Berardi
 
Posts: 542
Joined: Thu Sep 29, 2011 10:51 pm

Re: Betelgeuse

Postby Robin Leadbeater » Thu Feb 06, 2020 11:53 pm

Here is my updated trend since the end of last year. The spectrum is still evolving in the 7400A region relative to 2020-01-18

(2020-01-10 was taken using the ALPY 200 so lower resolution, the others are with the ALPY 600 at R~500)

Cheers
Robin

betelgeuse_20200204_915_Leadbeater.png
betelgeuse_20200204_915_Leadbeater.png (41.89 KiB) Viewed 1824 times
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Robin Leadbeater
 
Posts: 1520
Joined: Mon Sep 26, 2011 4:41 pm

Re: Betelgeuse

Postby James Foster » Fri Feb 07, 2020 1:08 am

To: Benjamin,

RE:"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."

Image
I finally had time to "play" with SpcAudace with some of my LhiresIII spectra of Betelgeuse. Here are the outputs I got when using the terminal command:
"spc_autoew filename.fit 6535 6595"

09Jan19 Data:
# Date: 2019-01-09T08:10:09
# JD: 2458492.8404
# EW(60.00=6535.00-6595.00)=15.165 A.
# Sigma(EW)=2.016 A.
# SNR=17.
# 15.165 2.016 17 2458492.8404 {EW(60.00=6535.00-6595.00)=15.165 A.}

13Jan2020 Data:
# Date: 2020-01-13T06:31:38
# JD: 2458861.7720
# EW(60.00=6535.00-6595.00)=3.858 A.
# Sigma(EW)=1.523 A.
# SNR=27.
# 3.858 1.523 27 2458861.7720 {EW(60.00=6535.00-6595.00)=3.858 A.}
[My SNRs are a little low!]

Do these look right?
Here's what I got using the "ew_courbe" command on the working directory containing only LhiresIII Ha data on Betelgeuse:
Image
When I used a larger range for the EW search with the "ew_courbe" (6510-6596) the EW trend was decreasing width; only 3 data points is probably too little.
I have a lot more to learn about your powerful program......I just need to be less afraid of "Command line terminal boxes!"

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
James Foster
 
Posts: 384
Joined: Sun Jan 24, 2016 7:14 am

Re: Betelgeuse

Postby Robin Leadbeater » Fri Feb 07, 2020 11:01 am

The measurement is clearly not working correctly as H alpha is obviously always in absorption but the EW on ~58825 is negative ie in emission. Cool stars like Betelgeuse are a very difficult case as all lines are blended and there is no clear continuum.
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Robin Leadbeater
 
Posts: 1520
Joined: Mon Sep 26, 2011 4:41 pm

Re: Betelgeuse

Postby etienne bertrand » Fri Feb 07, 2020 6:05 pm

The spectro Betelgeuse yesterday :
What is the emission ray at 6541 A ?
Image
etienne bertrand
 
Posts: 940
Joined: Mon Aug 31, 2015 11:26 am

Re: Betelgeuse

Postby Robin Leadbeater » Fri Feb 07, 2020 7:46 pm

etienne bertrand wrote:What is the emission ray at 6541 A ?


Is it emission or just the molecular band head surrounded by blended absorption lines? It is so hard to tell with cool stars. You can see the general shape in that region better in low resolution spectra
download/file.php?id=6602
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Robin Leadbeater
 
Posts: 1520
Joined: Mon Sep 26, 2011 4:41 pm

Re: Betelgeuse

Postby Benjamin Mauclaire » Fri Feb 07, 2020 9:02 pm

About EW measurement with SpcAudace, James worked with spc_autoew.
This is not a good idea here, with such a noisy continuum.
You need here to controle how continuum is fited. This can be achieved with "spc_ew" command that accepts continuum fiting parameters. Usage with examples can be found here:

http://spcaudace.free.fr/docs/index.php?doclink=ew.html#manual

Note that spc_ewcourbe which built EW=f(t) plot has a third optionnal argument: the polynomial order for continuum fiting.

Benji
Spcaudace spectroscopy software: saving you hundred hours of frustration.
Benjamin Mauclaire
 
Posts: 230
Joined: Thu Sep 29, 2011 10:14 am

Re: Betelgeuse

Postby James Foster » Sat Feb 08, 2020 2:06 am

To: Benjamin,

Yes I should have used the spc_ew for absorption lines....I did this, but disregarded the results. Here is what I have for my three (3) Alpha Orion spectra taken
with the LhiresIII with 2400 l/mm grating:

09Jan19:
SpcAudance Terminal Comm used:"spc_ew _aoriha_20190109_340.fit 6535 6595 6 n 2"
# Date: 2019-01-09T08:10:09
# JD: 2458492.8404
# EW(60.00=6535.00-6595.00)=1.956 A.
# Sigma(EW)=2.431 A.
# SNR=17.
# 1.956 2.431 17 2458492.8404 {EW(60.00=6535.00-6595.00)=1.956 A.}

11Dec19:
SpcAudance Terminal Comm used:"spc_ew _aoriha_20191211_381.fit 6535 6595 6 n 2"
# Date: 2019-12-11T09:08:51
# JD: 2458828.8811
# EW(60.00=6535.00-6595.00)=0.799 A.
# Sigma(EW)=1.810 A.
# SNR=23.
# 0.799 1.810 23 2458828.8811 {EW(60.00=6535.00-6595.00)=0.799 A.}

13Jan20:
SpcAudance Terminal Comm used:"spc_ew _aoriha_20200113_272.fit 6535 6595 6 n 2"
# Date: 2020-01-13T06:31:38
# JD: 2458861.7720
# EW(60.00=6535.00-6595.00)=0.805 A.
# Sigma(EW)=1.576 A.
# SNR=27.
# 0.805 1.576 27 2458861.7720 {EW(60.00=6535.00-6595.00)=0.805 A.}

Here is a SpcAudance plot of the last spectra showing the "EW Splice:"
Image

Not sure why I'm getting the positive EW values of 1.956A, 0.799A, & 0.805A for the Ha spectra for 09Jan19, 12Dec19, & 13Jan20 respectively.
It still looks like Betelgeuse EW at Ha has decreased significantly since last year.

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
James Foster
 
Posts: 384
Joined: Sun Jan 24, 2016 7:14 am

Re: Betelgeuse

Postby Benjamin Mauclaire » Sun Feb 09, 2020 11:43 pm

Hi James and others,

I transfered James' last post in Software/Spcaudace section:
http://www.spectro-aras.com/forum/viewtopic.php?f=50&t=2477&p=13757#p13757

EW measurement will follow there.

Benji
Spcaudace spectroscopy software: saving you hundred hours of frustration.
Benjamin Mauclaire
 
Posts: 230
Joined: Thu Sep 29, 2011 10:14 am

PreviousNext

Return to Supernovae

Who is online

Users browsing this forum: No registered users and 3 guests

x