Transcript Spectroscopic Monitoring of Be type Stars SAS Symposium - 26th may 2005

Spectroscopic Monitoring of Be
type Stars
SAS Symposium - 26th may 2005
Valerie Desnoux
Christian Buil
Spectrography is everywhere

On ESO-VLT, more than 90% are spectro related
Spectrographs
2005 - 6 months
8%
12%
5%
FLAMES
FORS1
19%
FORS2
10%
SINFONI
UVES
VIMOS
VISIR
Spectro-imagers
1%
ISAAC
10%
10%
MIDI
NACO
ULTRACAM
5%
16%
4%
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Which spectrograph ?
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Spectral range and Resolution
Ultraviolet
Infrared
Low resolution
High resolution
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Resolution, sensitivity...
Low spectral resolution
Low dispersion
Moderated light dilution
observations of faint objects
High spectral resolution
High dispersion
Magnifying glass effect
detailed spectrum
Resolution power
R = l / Dl
l: wavelength – Dl : resolved spectrum element
R = 100
R = 1000
R = 10000
-> low resolution
-> medium resolution
-> High resolution
Detectivity and spectral resolution are in competition
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LISA spectrograph
Long slit Intermediate resolution Spectrograph for Astronomy
Main characteristics
- Interchangeable grating
- Spectral resolution : Dl = 6 angströms (600 grooves/mm grating) or 3 angströms
(1200 g/mm grating)
- limiting mag on 8inches, 1 hour, 11th magnitude
- Integrated guiding system (reflective slit)
- Optimized for Schmidt-Cassegrain telescope (f/10 beam)
- Compatible with all CCD camera or Digital SLR
- Weight : 1.7 kg
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LISA spectrograph
Long slit Intermediate resolution Spectrograph for Astronomy
Optical layout
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LISA spectrograph
Long slit Intermediate resolution Spectrograph for Astronomy
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LISA spectrograph
Long slit Intermediate resolution Spectrograph for Astronomy
Fluorescent tube lamp : ideal for adjustement at home !
LISA + Nikon D70 + FSQ106 (4-inch trefractor) spectra
Arcturus (K1III)
Vega (A0V)
Beta Lyr (B7Ve)
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LHIRES3
Littrow HIgh REsolution Spectrograph
Main characteristics
- Interchangeable grating
- Spectral resolution : Dl = 0.35 angströms @ 6563 A (2400 g/mm holographic grating)
- 8inches, one hour, 6th mag limit
- Integrated guiding system (reflective slit)
- Optimized for Schmidt-Cassegrain telescope (f/10 beam)
- Compatible with all CCD camera or Digital SLR
- Weight : 1.9 kg
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LHIRES3
Littrow HIgh REsolution Spectrograph
Optical layout
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LHIRES3
Littrow HIgh REsolution Spectrograph
Pointing and guiding system
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LHIRES3
Littrow HIgh REsolution Spectrograph
First light:
April 26, 2005
LHIRES3 on a C11 telescope
Delta Sco
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Project team: Christian Buil, Yvon Rieugné, André Rondi
Prepared by Valérie Desnoux
Commercial devices
SBIG SGS
(Self-Guiding-Spectrograph)
Resolution max. : 2.4 A
4950 $
SBIG DSS-7
(Deep sky Spectrograph)
Resolution max. : 15 A
1495 $
Questar QMAX
(Solar Spectrograph)
Resolution max. : 0.17 A
4250 $
Commercial spectrographs are good indication of
the growing interest in Spectrography
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Other amateurs set-up
Dave Mais (USA)
Tom Kaye (USA)
Maurice Gavin (England)
CAOS group (Germany)
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Spectrograph domains

Spectrographs applications
Resolution
Type
Topics
Coments
Low
20-10 Ang.
LISA
DSS-7
Supernova - Comet Astéroïdes
Extended & faint objects
SBIG
Barèges
Be detection - Comet
Be study first entry
Spectral profile
monitoring
Temporal monitoring
The perfect tool for Be lines
studies
Multi-lines study
Temporal monitoring
Echelle spectro -> large
dispersion, pro study
Medium
5-1 Ang.
High
LHIRES
0.5 - .001 Ang.
High
"Echelle"
Musicos
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Iris - image and spectral preprocessings
http://www.astrosurf.org/buil
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Visual Spec - Spectral processings
http://valerie.desnoux.free.fr/vspec/
Manual of 118 pages
On line tutorials
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Pre-processings
Pre-processing,
registration, addition
Geometric distorsion
correction
Sky background
removal
Result
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Profil reduction: binning
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Binning: sum by column
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By manual selection of a zone or using an automatic
extraction routine (Iris or Visual Spec)
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Wavelength calibration
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Establish the relationship between pixel and
wavelength
–
Using an external calibration lamp
Neon
Mercure
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Atmospheric lines correction
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H20 lines are superimposed on the spectrum
–
–
Can be used to perfectly calibrated the spectrum
But shall be removed before any line analysis
H20 spectrum
6400 - 6700 A
Source: LPMA
Iterative parameters adjustements
- Smothing
- Intensity
H20
Interactive division
Véga
H-Alpha
Not corrected
H-Alpha
Corrected
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H-alpha line : a gold mine...
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emission
–
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H-alpha width and intensity
–
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Amount of material ejected
H-alpha V/R asymetry
–
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Ejection
Disk study
Separation of V & R peaks
–
Disk radius
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Equivalent width
LEQ - 28 Tau
1
40
35
30
25
20
LEQ
6540
6545
6550
6555
48000
6560
6565
6570
6575
6580
49000
50000
51000
52000
53000
Julian Day 2400000+
From observation to measurements and results...
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Be type Stars, what are they ?
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Discovered in 1867 by Secchi
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B-type stars = hot (blue)
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T = 20000 K = 3-4 Tsun
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non-supergiants
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M = 8 Msun
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R = 6 Rsun
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variables
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and...
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Be Type stars... "e" for emission
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which at least exhibits lines
in emission
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Be = B emission
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20% of B stars
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pecularitie or evolution ?
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B -> Be -> B -> Be
Koubsky et al. 2000
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Emission mysteries
Gas disk + rotation ?
Internal pulsations ?
Magnetic field ?
C. Ormerod
• Below critical rotation speed for ejection
Spectrography monitoring is key to
understand and explain the Be phenomena
Hubble Space Telescope Institute
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The Be historical survey
Pic du Midi Observatory
60cm telescope (24inches)
Be study started in 1992
Dos "Spec" software
TH7863 CCD chip
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And the story continues...
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The survey from "Home"...
280 stars monitored
Some with more than 30 observations over 10 years
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Astroqueyras & Musicos
Spectrograph Pro
1990/1991
First installed at 79 inches Pic du Midi
Transferred after Oléron school
Fiber optic, echelle spectrum, R 35000
Seminar organised by the association Astroqueyras
Regular missions, software & manuals "ready-to-use"
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MUlti SIte Continous Observing Spectrograph
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Resolution R=35000
380nm-880nm
80 orders (65-145) over 2 domains
Efficiency about 15%
460kg of material !
Ha
HeI
SiII
Hb
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Delta Scorpii
Delta Sco normal B-type star
Mv = 2.32
Ouburst to 0.4 in June 2000 photometry observation
Some H-alpha emission captured over
the last 5 years - proposed as Be-star
in 1993
Title: delta Scorpii
Authors: Fabregat, J.; Reig, P.; Otero, S.
Journal: IAU Circ., 7461, 1 (2100)
Publication Date: 07/2000
All other observations in the literature
present a normal absorption-line spectrum,
while our observations constitute the first
detection of emission lines in delta Sco,
confirming its Be-star nature.
Observed 1st by a
spectro amateur !
Clearly classified now as a Be star
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Delta Scorpii... Still a target
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H-alpha intensity
almost double in 6
months
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Photometry survey is
a good addition to
spectro
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Nu Gem
"The observations could indicate that there is a
one-armed oscillation of the disk ,i.e. the disk
is inhomogeneous and we see a denser part
rotate around the star with a period of 8-9
years. This star is thus an interesting target for
a long-term monitoring." Coralie Neiner
Mar '02
Jan '04
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Zeta Tau
Be binary star, always changing...
B2 subgiant
m=3.00
420 yrl
L=5700sun
Vrot=330km/s
Disk 64xSun diameter
Star 5xSun diameter
Lower mass companion @0.36yrl
Rotation period 132.91 days
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From right to left: Dec 2001, Jan 2002, Aug 2002, Feb 2003, Oct 2003, Jan 2004, Aug 2004, Oct 2004, Mar 2005
Prepared by Valérie Desnoux
HD206773
A spectacular outburst of a Be star !
From 30-June-2001 to 17-dec-2001
Spectrograph LHIRES + telescope of 8 inches
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Omega Orion - temporal monitoring
From August
2001 to February 2002
 w Ori, a classical Be star (fast
rotator!)… with a magnetic field
(Neiner et al. 2003)
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Share the data
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Find, meet the interested professional
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Publish the data
 Participate to
mission at pro-am
observatories
 Join ARAS...
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Oléron -
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A Pro-Am 3 days seminar sponsored by the CNRS Pros
Mix of professional and amateur presentations
http://www.obs-nice.fr/formation/Oleron2003/Index_JP.htm
http://astrosurf.com/aude
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Spectro seminar in France
 As
a follow-up of the Oleron
school
 Sponsored by the HauteProvence Observatory
 20+
observers, with
telescope and spectrographs
 Night:
observations, Day:
processings
(1st exoplanet obs.)
Will do it again this year !
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Join ARAS ! On Spectro-l
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International group of
discussion on a Yahoo list
http://groups.yahoo.com/group/spectro-l/
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Professionals on-line
Call for observations
Be
Star call by Ernst Pollman:HR2142
Hello list!
During the next months for Be-starobserver could be again interesting
HR2142. I have received of this star
during the visibility 09/2003-04/2004 16
spectra which led to the summarized result
in the appendix. The professional research
needs data for a better understanding
regarding the phase-dependent development
of the shell-line and the V/R-behavior.
Therefore a contribution of amateur
observations seems meaningful
http://astrosurf.com/aras/
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Publications are possible
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Come together...
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Amateurs, all over the world can monitor
on a long time range a phenomena
Share first tests and results is
encouraging
Collaborate with professionals
Participate to the call for observations
Be stars survey is just one example...
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Spectrography
Imagination at work ®
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