! wavelength shifts in solar-type spectra ! dainis dravins, lennart lindegren, hans-günter ludwig,...

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WAVELENGTH SHIFTS IN WAVELENGTH SHIFTS IN SOLAR-TYPE SPECTRASOLAR-TYPE SPECTRA

WAVELENGTH SHIFTS IN WAVELENGTH SHIFTS IN SOLAR-TYPE SPECTRASOLAR-TYPE SPECTRA

!Dainis Dravins, Lennart Lindegren, Hans-Günter Ludwig, Søren Madsen

Lund Observatory, Sweden

Cool Stars 13, Hamburg, July 2004

WAVELENGTH SHIFTS !WAVELENGTH SHIFTS !WAVELENGTH SHIFTS !WAVELENGTH SHIFTS !

Usually interpreted as “Radial

velocity”

"Definition" of radial velocity"Definition" of radial velocity"Definition" of radial velocity"Definition" of radial velocity

"The radial component is stellar movementtoward or away from us. This motion

mustbe measured from a star's spectrum."

C.De Pree & A.Axelrod: The Complete Idiot's

Guide to Astronomy, p.258 (1999)

Astrometric radial velocities IAstrometric radial velocities I

Dravins, Lindegren & Madsen, A&A 348, 1040

Astrometric radial velocities IIAstrometric radial velocities II

Dravins, Lindegren & Madsen, A&A 348, 1040

Astrometric radial velocities IIIAstrometric radial velocities III

Dravins, Lindegren & Madsen, A&A 348, 1040

Pleiades from Hipparcos Proper motions over 120,000 years

STARPATHS (200,000 y)STARPATHS (200,000 y)

Madsen, Dravins & Lindegren, A&A 381, 446

Hyades from Hipparcos D. Dravins, IAU Symp. 215 (2004)

Hyades lineshifts Madsen, Dravins & Lindegren, A&A 381, 446

Gravitational

redshifts

D. Dravins

IAU Symp. 210

STELLAR GRANULATIONSTELLAR GRANULATION

Hans-Günter Ludwig (Lund)

“Beta Hydri” [G2 IV] Synthetic Fe I line & mirror

profileDravins, Lindegren, Nordlund & VandenBerg, ApJ 403, 385

Lineshift & stellar rotation

Madsen, Dravins & Lindegren, A&A 381, 446 & Dravins, IAU Symp. 215

Atmospheric shockwaves (Hartmut Holweger,

Kiel)

PROGRESS IN SCIENCEPROGRESS IN SCIENCEPROGRESS IN SCIENCEPROGRESS IN SCIENCE

is driven by ...

Confrontation between theory and observation

Falsification of theoretical hypotheses

New observational measures requiring explanation

PROGRESS IN SCIENCEPROGRESS IN SCIENCEPROGRESS IN SCIENCEPROGRESS IN SCIENCE

is not driven by ...

Agreement between theory and observation

(when they agree, not much new can be learned)

PROGRESSPROGRESS ININ STELLARSTELLAR PHYSICSPHYSICSPROGRESSPROGRESS ININ STELLARSTELLAR PHYSICSPHYSICS

Requires disagreement between

theory and observation !

Non-LTE in convective lineshifts

Dravins & Nordlund,

A&A 228, 184

Dravins, IAU Symp. 210

Fe II lineshifts at solar

disk center

Dravins, IAU Symp. 210

Solar data:

Allende Prieto & García López, A&AS

131, 341

Laboratory wavelengths:

S. Johansson (Lund)

Fe II lineshifts at solar

disk center

2-D models by Aleksey Aleksey

GadunGadun, Kyiv, Ukraine

Dravins, IAU Symp. 210

Ni I lineshifts at solar

disk center

Dravins, IAU Symp. 210

Solar data:

Allende Prieto & García López, A&AS

131, 341

Laboratory wavelengths:

U. Litzén, J.W.Brault, A.P.Thorne, Phys.Scr.

47, 628

429 Ti I bisectors at solar

disk center

Solar data:

“Hamburg photosphere” H.

Neckel, Solar Phys. 184, 421

Kurucz et al.: Solar Flux Atlas from 296 to

1300 nm

Laboratory wavelengths:

P. Forsberg, Phys.Scr. 44, 446

U. Litzén (Lund)

Same spectral line in

different stars

Dravins, IAU Symp. 210

Adapted from

Dravins & Nordlund, A&A 228, 203

IMAGING STELLAR SURFACESIMAGING STELLAR SURFACESIMAGING STELLAR SURFACESIMAGING STELLAR SURFACES

ESO VLTI : AT1 and domes of the 8.2 m unit telescopes

Same spectral line in

different stars

Adapted from

Dravins & Nordlund, A&A 228, 203

IMAGING STELLAR SURFACESIMAGING STELLAR SURFACESIMAGING STELLAR SURFACESIMAGING STELLAR SURFACES

IMAGING STELLAR SURFACESIMAGING STELLAR SURFACESIMAGING STELLAR SURFACESIMAGING STELLAR SURFACES

Optical VLA

Antoine Labeyrie (Laboratoire d'Interférométrie Stellaire et Exo-planétaire)

WAVELENGTH SHIFTS !WAVELENGTH SHIFTS !WAVELENGTH SHIFTS !WAVELENGTH SHIFTS !

A new diagnostic tool for stellar physicsenabled by ...

Astrometric radial velocities throughout the Hertzsprung-Russell diagram

High-resolution spectrometers with accurate wavelength calibration

Accurate laboratory wavelengths for several atomic species

The End

...

Astrometric radial

velocities from

perspective

acceleration

Dravins, Lindegren & Madsen, A&A

348, 1040

UNDERSTANDINGUNDERSTANDING STELLARSTELLAR

SURFACESSURFACESUNDERSTANDINGUNDERSTANDING STELLARSTELLAR

SURFACESSURFACES

theory and observations interact about...

Spectral-line strengths

Spectral-line widths Line-profile shapes

Line asymmetries and bisector patterns Time variability in irradiance and

spectrum

Stellar surface imaging Relative & absolute wavelength shifts