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From large velocities to tiny accelerations
- the successful Doppler detection of exo-planets
From large velocities to tiny accelerations - the successful Doppler - - PowerPoint PPT Presentation
From large velocities to tiny accelerations - the successful Doppler - - PowerPoint PPT Presentation
From large velocities to tiny accelerations - the successful Doppler detection of exo-planets gordon walker spectrum display complete UBC Isocon digital camera system ADC 1970 exposure time Interdata computer 4K memory Isocon + tape
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camera mirror
Isocon in DAO 1.2-m telescope McKellar coudé spectrograph
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1956 [obs 1897 to1947] η Boo G0 IV 1.2 m P=495 d e=0.232 m2 = 0.45 m
10 8 6 4 2
- 2
- 4
- 6
km/s
0 100 200 300 400 500 600
days jupiter in the same orbit +20 -11 m/s
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slit
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w d
qn photons/Å N spectral lines
difference signal
δλ
shot-noise limit δλ ~ w/d2 qn.N 10 m/s ~ 3x10-4 Å
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RV scanner mask
y x
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HD 114762 F9 V mV=7.3 280 obs σRV = 0.42 km/’s 84 d m2 sini = 11 mJ e = 0.26 Latham, Stefanik, Mazeh, Mayor, Burki -- CfA speedometer & CORAVEL (1989)
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John Glaspey & Greg Fahlman 1973 Si diode
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Reticon self-scanned Silicon diode arrays 256 1024 1872 15 x 750 μm
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Campbell & Walker DAO 1978 – CFHT 1980 Ca II 120 Å R~50,000
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CFHT 3.6-m HF (1000 C)
1980
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CFHT
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8717 Å HF 8738 Å impact of instrumental profile asymmetry ?
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relative displacement of lines convolved with a 610 m/s asymmetric instrumental profile
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30 km/s ~1 Å
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1988 A SEARCH FOR SUBSTELLAR COMPANIONS TO SOLAR-TYPE STARS Campbell, Walker & Yang 12 late-type stars – 8 (4x2) nights per year [later only 6] external error 13 m/s flagged potential planetary companions to: γ Cep - single line SB + superimposed 2.7 y 25 m/s amplitude ε Eri 1989 YELLOW GIANTS – A NEW CLASS OF RADIAL VELOCITY VARIABLE ? Walker, Campbell, Yang & Irwin 1992 Alex Wolszczan & Dale Frail – terrestrial companions to B1257 +12 1995 Ana Larson – β Gem 590 d planetary period [also Cochran & Hatzes] 1995 A SEARCH FOR JUPITER MASS COMPANIONS TO NEARBY STARS 21 stars 1980 – 92
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Marcy & Butler 5019 to 5872 Å = 853 Å 1987
I2
500 C
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Hamilton échelle (Vogt) R = 62,000
Shane 3-m
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template stellar spectrum inst PSF removed star + I2 as observed R~106
I2
template `2 Å’ model
σRV ~ 3 m/s
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11.6 Å telluric O2 α-band
Cochran & Hatzes MD I 1988 Tull coudé sp’graph R~210,000 TI 800x800 2.7-m Harlan Smith
2.7-m Harlan Smith
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K1 IV binary period ~ 57 y
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HF O2 I2 9.6 Å I2 850 Å
Ppl = 2.48 y msini = 1.7 mJ
e = 0.12
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ELODIE
(Baranne)
Mayor & Queloz 1994
fibre inputs OHP 1.93-m
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R = 42,000 67 orders Tk 10242 3900 to 6800 Å ELODIE only ★ + Th/Ar arc ★ twin fibre feed light scrambling stable psf
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51 Peg Mayor & Queloz 1995 P = 4.23 d m sini = 0.47 J
σRV ~ 13 m/s
HARPS σRV ~ 1 m/s 2003
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σRV ~ 3 m/s
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