Transcript Diapositive 1

IAC science with the prototype SONG
node
at Tenerife
Katrien Uytterhoeven
research group
‘Solar and Stellar Seismology and Extrasolar
planet searches’
(7 staff, 2 PostDocs, 3 PhD)
Seismology
Interests in SONG:
* the Sun-as-a-star
* solar-like stars
* red giants
* SdB stars
* δ Sct, γ Dor
* β Cep, SPB
* OB supergiants
* binaries with pulsating components
planets
* follow-up of planet candidates
Massive main-sequence pulsators
= γ Dor, δ Sct, SPB, β Cep
Seismic study requires identified (l,m) modes!
Problem: mode-ID does not rely on regularity of frequency spectrum
δ Sct HD50844
Mode-ID via
line-profile analysis!
(l,m)
* amplitude and phase
distribution across line-profile
* velocity moments
GOAL: SONG RV time-series
a) mode-identification!
b) test and improve seismic models
Sun-as-a-star: SONG and Mark-I
Mark-I
* operational at Obs. Teide since 1976
* full-time monitoring since 1984
* RV of the Sun through potassium KI 769.9 nm line
* sampling rate: 2sec
GOAL:
daytime solar spectra with SONG
a) compare simultaneous (same site!) Mark-I and SONG observations
(resample to same sampling rate)
b) evaluate quality and sensitivity of SONG solar observations
Planet transits
Use SONG photometry to confirm transit candidates through color
changes during transit
See talk by Brandon!
> 50 staff scientists
> 65 post-docs
> 35 PhD students
Interests in SONG from IAC research
groups other than the group on
‘Solar and Stellar Seismology and Extrasolar
planet searches’
i. Wavelength variations in Solar spectral lines
twilight sky spectrum
HET McDonald
observatory
* 1 yr solar orbit
ampl=0.507 km s-1
* 1 d Earth orbit
(not well covered)
+ other deviations!
ΔT = 1750 days
Origin of deviations?
* changes in granulation properties along solar cycle
* presence of planets
e.g. Jupiter: 13 m s-1 over 12yr
GOAL:
twilight sky spectra with SONG and I2 cell
a) investigate wavelength stability of the solar spectrum
b) demonstrate that deviations due to a Jupiter-size planet can unambigously
be found
c) study stellar activity
ii. Low mass X-ray binaries
Rémon Cornelisse
* Compact Binaries (Porb~hrs), primary is
compact object (neutron star, black hole).
* Roche-lobe overflow, matter accreted via
accretion disk.
* Inner accretion disk gives rise to X-rays.
* optical emission due to Reprocessing of Xrays in outer accretion disk
* Different optical wavelengths probe different
parts of the outer accretion disk
Large night to night changes in lightcurve morphology
Origin? changes in accretion disk
due to precession or the presence of a warp?
Goal: ~1 week continuous multi-colour photometric monitoring with the SONG
network
a) understand the origin of the lightcurve changes
b) understand physics of the accretion disk
iii. Classical Novae at maximum light
Alessandro Ederoclite
Nova = thermonuclear explosions on surface of white dwarf accreting mass in a
close binary
* brightening (< V=10mag few weeks)
T Pyx, lightcurve
* FeII or He/N line absorption
Mag
* mysterious absorption systems (THEA)
questions:
* origin of absorption lines?
* model that fits at all wavelengths ?
MJD - 2450000
T Pyx, FIES spectra
15.04.2011
GOAL:
few SONG spectra per
day (without I2 cell)
during max light of novae
follow-up optical thick and
thin phase
Time
a) describe chemistry
b) describe dynamics of
explosion
30.05.2011
iv. Chemical analysis of EBs
Carlos Allende Prieto
Well-detached EBs are best calibrators for
models of stellar structure and evolution
accurate orbital parameters, M*, R* !
BUT! spectral chemical analysis is lacking!
GOAL:
SONG spectra (without I2 cell) of well-known, bright, well-detached EBs
at max separation
a)
derive metallicity and chemical abundances of binary components
b) calibrate models stellar structure & evolution
v. Multiple populations in globular clusters
Antonino Milone
Many globular clusters show multiple
sequences!
GOAL:
SONG spectra of bright stars in GCs (filling
program)
derive chemical and dynamical
properties
and try to solve:
a)abundance anomalies
b) multiple sequences
c)horizontal branch morphology
CMD of NGC 2808 with isochrones
vi. macroturbulent broadening in OB supergiants
Sergio Simón Díaz
OB SGs show extra line broadening:
‘macrotubulence’
origin?
pilot study!
signature of collective effect of
pulsations?!
GOAL:
time-series of SONG spectra of
bright
OB supergiants
a) understand ‘macroturbulence’
b) improve atmosphere models of
OB SGs
c) first seismic studies of OB SGs!
promising!
IAC science
many interesting filling programs and
additional SONG science programs
for SONG-OT!