Sizing up the Stars - Department of Physics and Astronomy ...

Sizing up the Stars 

Diameters of A, F, and G Dwarfs 

with the CHARA Array 

Tabetha S. Boyajian 

Georgia State University 

Department of Physics and Astronomy 

2007-04-24 Prospectus Talk 1

Committee Members 

• Hal McAlister- Advisor 

• Doug Gies 

• Paul Wiita 

• Todd Henry 

• Nikolaus Dietz 

• Gerard Van Belle (Caltech/MSC) 

Additional Thanks! 

Ellyn Baines, Deepak Raghavan, Chris Farrington 

Rajesh Deo, Krupa Gandha, Erika Grundstrom, Steve Williams, Stephen Rafter 

Jao Wei-Chun , Alvin Das, Ginny McSwain, Dave Berger 

The CHARA Array Staff 

2007-04-24 

2

Outline 

• Summary of how I spend my time at GSU 

• Sizing up the stars (my dissertation) 

Historical background and importance of stellar 

diameter measurements 

The CHARA Array 

My goals 

Target selection 

Observing techniques, procedures, data reduction 

Results so far 

• Summary and conclusion 

2007-04-24 

3

Sizing Up My Research at GSU… 

• Masters thesis 

Optical spectroscopy of massive stars 

2007-04-24 

• The Massive Runaway Stars HD 14633 and HD 15137: Boyajian et al. 2005 

 

Contributing work (with Dr Ginny McSwain) 

• Runaway star formation and ejection scenarios (2006) 

• Dynamical simulations, Radio and X-ray observations of runaway stars 

(2006) 

• The Massive Double Lined Binary HD 1383: Boyajian et al. 2006 

• HD 37366 and HD 54662: Potential Targets for Long Baseline Optical 

Interferometry: Boyajian et al. 2007 

• Radial Velocities of Six OB Stars: Boyajian et al. (Submitted) 

• Optical Spectroscopy of Southern Runaway O-stars 

• PhD thesis 

Long Baseline Interferometry with the CHARA Array 

• Angular Diameters of Hyades Giants 

• Resolving Massive SB2’s with the CHARA Array 

• Angular Diameters of Main Sequence A, F, and G stars with the CHARA 

Array 

4

Sizing Up the Stars- 

• How to measure stellar sizes 

The angular sizes of stars are TINY in the sky, so we must be 

clever on how to resolve them 

• Target selection 

Find stars that are close to us 

Find stars that are large, despite their distance 

• Engineering 

Build instruments sensitive to resolving these kind of objects 

Direct methods to measure stellar sizes: 

• Long baseline optical interferometry 

• Eclipsing binaries 

• Occultations (Planetary and Lunar) 

• Speckle Interferometry 

• For my thesis, I am targeting the nearby A, F, and G 

main sequence stars that can be resolved with great 

accuracy using the CHARA Array 

2007-04-24 

5

Sizing Up the Past 

• There is a paucity of ACCURATE diameter 

measurements for mid-type stars 

20% 

O,B,A,F: 

open=NSII, 

closed=JO 

G,K,M: open=LO, 

dot=CERGA, 

slash=speckle, 

closed=LBI 

10% 

5% 

2007-04-24 

6

Main Sequence A, F, and G Star Diameters 

Fundamental Stellar Properties 

IAU Symposium 1997 (J. Davis) 

My 

thesis 

sample 

range 

2007-04-24 

All Interferometric Measurements 

Interferometric measurements 

with < 5% error on diameter 

7

Emphasizing the Sizeable Importance 

• Size DOES Matter!!! (sorry fellas) 

Interferometry… Big Baseline = AWESOME resolution 

Fundamental stellar Astronomy and Astrophysics… 

• Effective temperatures T eff 

• Absolute Luminosities 

H-R Diagram 

• Constraint for model stellar atmospheres and evolution 

• Single star VS binary star radii (from eclipsing binaries) 

• Metallicity and age 

• Direct diameter measurements with long baseline 

optical interferometry of a large sample of stars, 

enables us to derive relationships (e.g., with 

photometry) to characterize an even larger number of 

stars, too far away (small) to observe with 

interferometry 

2007-04-24 

8

Stellar Diameters and Interferometry 

Once upon a time… 

• 1921 

Michelson and Pease 

used the 20-ft 

interferometer 

attached to the 100- 

inch Hooker telescope 

on Mt. Wilson to make 

the first direct diameter 

measurement of a star 

(other than the Sun) 

2007-04-24 

9

Progress in Stellar Interferometry 

• 1950 – 1972 

Narrabri Stellar Intensity Interferometer 

(NSII) 

• 32 diameters of stars in the visible 

wavelength: Hanbury Brown, R., Davis, J. 

Allen, L. R. 1974 

• Empirical temperature scale for stars hotter 

then the sun is based on this data (7 of these 

32 are main sequence stars, all hotter than 

F2); Code, A. D., Bless, R. C., Davis, J., 

Brown, R. H. 1976 

Fundamental H-R Diagram 

Based Directly on 

Observations 

Photo from Dr John Davis: 

http://olbin.jpl.nasa.gov/photos/nsii.html 

2007-04-24 

10


Funded by the National Science Foundation, Georgia State 

University, the W.M. Keck Foundation, and the David and 

Lucile Packard Foundation 

S 

LA 

W 

2007-04-24 

E 

Mt Wilson, CA 

11


• Optical/IR interferometer 

with six 1-m telescopes in 

Y configuration 

• 331-m maximum baseline 

yields sub-milliarcsecond 

angular resolution 

• The BIGGEST in the 

WORLD!!! 

2007-04-24 

12

The CHARA Array and AROC 

Cleon Arrington Remote Operations Center 

• Remote observing from 

downtown Atlanta since 

Fall 2006!!! 

• Currently we are able to 

operate multiple beam 

combiners simultaneously 

(What an effective way to 

optimize telescope time, 

as well as avoid bears 

and rattlesnakes!!!) 

Hal 

Fringes! 

2007-04-24 

PJ Chris Me Deepak Ellyn 

13

Interferometer Basics 

• Geometric path length 

difference from the source and 

the pair of telescopes is 

equalized and beams are 

combined to make fringes 

• An interferometer measures 

the Visibility of the object, which 

describes the time averaged 

fringe intensity: 

V 

= 

I 

I 

max 

max 

− I 

+ I 

min 

min 

Diagram courtesy of Hal McAlister 

• Visibility is related to the 

angular size (θ) of the star 

V=0 star is resolved 

V=1 star is unresolved 

2007-04-24 

1 

V 

I 

I 

max min 

= 014 

max 

− 

+ 

I 

I 

min

Visibility of a Single Star 

• The visibility function for 

single star: 

V = 2∗ J1( 

πBθ 

λ) 

( πBθ 

λ) 

1 

0.8 

0.6 

Θ=1 mas 

• The CHARA Array is the 

only long baseline optical 

interferometer capable of 

accurately resolving 

stars d1 mas 

This is 90% of stars in my 

project 

2007-04-24 

V 2 

0.4 

0.2 

0 

Θ=8 mas 

Θ=2 mas 

Θ=4 mas 

0 100 200 300 400 500 

Baselime HmL 

Long Baselines are crucial 

to resolving these type of 

stars! 

15

Main Sequence A, F, and G Type Stars 

with the CHARA Array 

• Target Selection Goal 

Determine diameters for a 

large sample of stars to better 

than 4% accuracy 

• Target Selection Criteria 

Visibility Curve Sampling: 

• Visibilities measured farther 

up the curve (closer to 1) 

yield large error in diameter 

• To achieve 4% accuracy goal, 

the target must be resolved at 

the longest baseline/shortest 

wavelength to V< 0.5 

K-Band limit: θ> 0.65 mas 

H-Band limit: θ> 0.50 mas 

V 2 

V 2 

1 

0.8 

0.6 

0.4 

0.2 

1 

0.8 

0.6 

0.4 

0.2 

θ=0.65 m as 

330-m 

Kband 

Hband 

0 100 200 300 400 

Baseline θ=0.5 mas HmL 

2007-04-24 

0 100 200 300 400 16 

Baseline HmL

Target Selection 

A0 V 

A5 V 

• HIPPARCOS Catalogue query 

Spectral type 

• Defined by B-V colors 

V magnitude (limit) 

• Defined by V-H colors of spectral type 

and H-band sensitivity limit of CHARA 

(H

Downsizing the Target Sample 

• Investigate literature on each star returned in query 

• Binaries 

Spectroscopic binaries: rejected 

Double stars 

• Companions < 2” away: rejected 

• Companions 2 – 5” away: flagged 

• Companions > 5” away: OK 

• Variable stars or abnormal atmospheric activity: rejected 

or flagged 

• Rapidly rotating stars: flagged 

• Diameter measurement previously determined with the 

CHARA Array (Baines, van Belle, etc.): flagged 

2007-04-24 

18

Target Selection 

• Total size of 90 stars (including flagged targets) 

• Well sampled over the range of spectral types, with 

moderate spread in main sequence, and age 

0 

Boyajian's Sample 

1 

2 

Mv 

3 

4 

5 

6 

7 

-0.05 0.15 0.35 0.55 0.75 

B-V 

2007-04-24 

19

Observations with the CHARA Array 

• CHARA Classic beam combiner 

K band: ~1/3 of targets 

Some overlap 

H band: ~2/3 of targets 

• Longest available baselines 

Ideally 2 baselines for each target S 

• S1/E1 and S1/W1 or E1/W1 

• Orthogonal to each other for 

maximum U-V plane coverage, 

and visibility curve sampling 

• 10 data points for each target 

per baseline 

E 

• chara_plan and chara_planB (GO Deepak!!!) 

Tools used to plan observing setup and strategy 

W 

2007-04-24 

20

Visibility Curve Sampling 

350 

• Baseline coverage 

Any one baseline provides 

moderate change in the 

projected baseline for an 

object as it moves across the 

sky during the night 

A second baseline extends the 

confidence of the true nature 

of the visibility curve 

• U-V plane coverage 

Also an effect of object moving 

across the sky, and provides 

insight in the objects true 

shape 

350 

1 

0.8 

chara_plan for S1/E1 

Visibility 

of a Single Star 

One night: 

shorter baseline 

V 

0 

V 

0 

V 2 

0.6 

0.4 

One night: 

longer baseline 

350 

350 0 350 

2007-04-24 

U 

2.5 hours 

later 

350 

350 0 350 

U 

0.2 

0 100 200 300 21 400 

Baseline HmL

Bracketed Observations 

• When you observe, the data you collect yield the raw (instrumental) 

visibility that depends on various factors in the observing conditions 

• To measure the true visibility of an object: 

Observe a calibrator star, with known diameter, to transform the data 

into true visibility of the object of unknown diameter 

Observing sequence: 

Calibrator - Object - Calibrator - Object – Calibrator 

One bracket 

One bracket 

A calibrator star should be 

• A single star (wide companions are OK) 

• Close-by in the sky (

Calibrator Star Selection 

• GetCal* web query (MSC-Caltech): 

User inputs HD# of object, (and possibly additional restraints 

such as luminosity class preference, magnitude limits, etc.) 

Output is a list of possible calibrators with: 

• V, K magnitudes 

• Simbad spectral types (YUK!!) 

• Estimated angular diameter 

• Distance in degrees to your object in the sky 

• You must investigate these possible calibrators in all 

available literature/catalogs for duplicity and variability- 

They must be NORMAL! 

• Choose two calibrators per object (that pass the test), 

chances are that you will run into a few bad eggs, which 

will contaminate your data 

2007-04-24 

*available at http://mscweb.ipac.caltech.edu/gcWeb/gcWeb.jsp 

23

Spectral Energy Distribution Fits 

• Determination of radii from 

absolute flux of star (Gray 

1967, 1968) 

• Collect published photometry 

available for each calibrator, 

and convert magnitudes into 

flux’s (F n ) 

• Run Kurucz model 

atmospheres, to get absolute 

flux at stars surface (F n ) 

• Model continuum is correctly 

matched with observations by: 

Varying T eff 

and log g of model 

Applying the standard galactic 

extinction curve 

• Determine the “known angular 

diameter” of the calibrator 

4πr 

F = 4πR 

θ 

distance 

R 

2 

= 

ν 

Flux 

received 

at Earth 

R 

r 

= 

⎛ 

⎜ 

⎝ 

2 

Stellar 

radius 

F 

I 

ν 

ν 

I 

ν 

Flux 

emitted at 

stellar 

surface 

⎞ 

⎟ 

⎠ 

1 

2 

2007-04-24 

24

Example SED Fit: HD 159026 

®= Observed photometry = Kurucz model 

U B V J H K 

T=5900 K 

2007-04-24 

25

T=6000 K 

2007-04-24 

26

T=6150 K 

2007-04-24 

27

T=6250 K 

2007-04-24 

28

T=6350 K 

2007-04-24 

29

Data Reduction and Calibration 

• The data is reduced using both Hal’s and Theo’s routines 

• Calibrating the data 

Get the time interpolated values of V Inst/Calib 

at the time your object was observed 

Then, with the “known” angular diameter of the calibrator (V True/Calib 

), use this 

Calibrated 

Visibilities 

relation to get true visibilities of your object for each bracket: 

VInst 

/ Obj 

VTrue 

/ Obj 

= VTrue 

/ Calib 

V 

0.5 

V True/Obj 

From SED 

Inst / Calib 

0.4 

V Inst/Calib (Interpolated) 

VISIBILITY 

0.3 

0.2 

0.1 

V Inst/Calib 

V Inst/Obj 

Measured 

at 

telescope 

2007-04-24 

Bracket 

0 

2007.25542 2007.255455 2007.25549 2007.255525 2007.25556 

EPOCH 

30

Limb Darkening and 

Stellar Diameters 

• Limb darkening describes the diminishing intensity of a 

star from the center to the limb. It is an effect of: 

Density of star decreases as distance from the center increases 

Temperature of star decreases as distance from center 

increases 

• Limb darkening is wavelength dependent, and it has 

minimal influence on stellar diameter in the infrared 

• SED fit made for object also 

Get preliminary T eff and log g estimates 

Look up the linear limb darkening coefficient for object’s T eff and 

log g at wavelength of observation (K or H band) in Claret et al. 

1995 

2007-04-24 

31

Data Analysis: Diameter Fitter 2007 

• Interpreting the calibrated visibilities 

Diameter Fitter 2007, written in MathCad by Hal 

McAlister 

Target’s data is fit to the visibility curve for UD and LD 

angular diameters to find its angular size. 

• Linear radius of target also found with 

HIPPARCOS parallax. 

• Some examples: 

2007-04-24 

32

LIMB DARKENED DISK FIT 

HD 97603: A4V 

UNIFORM DISK FIT 

1 

mDiamL= 

1.306 

1 

mDiamU= 

1.284 

0.8 

σmDiamL= 

0.037 

σresL = 0.027 

0.8 

σmDiamU= 

0.036 

σresU = 0.027 

Visibility 

0.6 

0.4 

wmDiamL= 

1.316 

σwmDiamL= 

0.036 

Visibility 

0.6 

0.4 

wmDiamU= 

1.294 

σwmDiamU= 

0.035 

0.2 

0.2 

0 

0 

0 50 100 150 200 250 300 350 

Baseline (mlambda) 

0 50 100 150 200 250 300 350 




1 

1 

0.8 

0.8 

Visibility 

0.6 

0.4 

Visibility 

0.6 

0.4 

0.2 

0.2 

0 

2007-04-24 

138 140 142 144 146 148 150 152 154 


0 

138 140 142 144 146 148 150 152 154 


33

HD 118098- “Troubling fit” 



1 

mDiamL= 

0.880 

1 

mDiamU= 

0.869 

0.8 

σmDiamL= 

0.087 

σresL = 0.057 

0.8 

σmDiamU= 

0.086 

σresU = 0.057 

Visibility 

0.6 

0.4 

wmDiamL= 

0.862 

σwmDiamL= 

0.070 

Visibility 

0.6 

0.4 

wmDiamU= 

0.851 

σwmDiamU= 

0.069 

0.2 

0.2 

0 

0 

0 50 100 150 200 250 300 350 


0 50 100 150 200 250 300 350 




1 

1 

0.8 

0.8 

Visibility 

0.6 

0.4 

Visibility 

0.6 

0.4 

0.2 

0.2 

0 

0 

2007-04-24 120 125 130 135 140 145 150 

120 125 130 135 140 145 150 



34

Troubling Fits- Data Reduction 

• Visibility measured in two different ways through data 

reduction 

VisUV Calc (Hal): measures the fringe visibility by fitting the 

fringe envelope 

reduceir (Theo): measures the fringe visibility by integrating the 

power spectrum 

• Reducing the data carefully enables us to be critical to 

bad data caused by 

Vibrations in the lab 

Horrible seeing or bad fringe tracking 

Observer error 

• Bad calibrators 

• Bad observing strategy 

2007-04-24 

35

HD 118098: Bracketed Observations 

2007-03-10 

Summary of Results for: HD 120066 

UT = ( 9 2 30) 

RA = ( 13 46 57) 

darkA = 50 darkB = 70 

LT = ( 1 2 30) 

Dec = ( 6 21 1) 

avIA = 174 avIB = 159 

LST = 12.3903 LSTrange = 0.0417 ΓA = 1.000 ΓB = 0.977 

HA = 22.61 

HArange = 0.04 

avBP = 152 σBP = 8 

Alt = 56.09 

Altrange = 0.33 

Freq0 = 155 DithStep = 0.333 

Azm = 320.58 

Azmrange = 0.95 avSel = 2.96 Baseline = 12 

U = 180.179 

Urange = 1.316 

Results: 

V = 261.455 

Vrange = 0.217 

BY = 2007.187209 

Scanlength = 558 Nscans = 242 

lpass = 20 

Rejects = 134 

JD = 54169.8767 

BW = 30 

cutoff = 1.00 

Vamp = 0.201 

λ = 2.15E-006 

range = 30 

Vps = 0.195 

σVis = 0.015 

350 

= UTDate = ( 2007 3 10) 

SeqNo = 1 

B = 317.529 Brange = 0.568 

Θ = 55.428 Θrange = 0.218 

Power 

0.15 

0.1 

0.05 

0 

MEAN FRINGE POWER SPECTRA 

Red = Signal 

Blue = Noise 

Green = Dark 

Black = Smoothed, 

Subtracted Signal 

V 

0 

40 

0.05 

Number 

20 

350 

350 0 350 

U 

0 

0 1 2 

Visibility 

0.1 

0 100 200 300 400 500 

1 

(dots given zero wgt) 

Fringe Position 

500 

Visibility 

0.5 

0 

0 50 100 150 200 

Fringe Number 

0 50 100 150 200 

Fringe Number 

2007-04-24 

36


UT = ( 9 16 0) 

RA = ( 13 34 42) 


LT = ( 1 16 0) 

Dec = ( 0 35 45) 

avIA = 855 avIB = 748 


HA = 23.04 


avBP = 154 σBP = 7 

Alt = 53.76 



Azm = 335.07 


U = 165.484 


Results: 

V = 251.087 


BY = 2007.187235 


lpass = 20 

Rejects = 131 

JD = 54169.8861 

BW = 30 


Vamp = 0.150 

λ = 2.15E-006 

range = 30 

Vps = 0.197 

σVis = 0.010 

350 

= UTDate = ( 2007 3 10) 

SeqNo = 1 

B = 300.718 Brange = 0.825 

Θ = 56.613 Θrange = 0.245 

Power 

0.15 

0.1 

0.05 

0 


Red = Signal 

Blue = Noise 

Green = Dark 



V 

0 

350 

350 0 350 

U 

Number 

60 

40 

20 

0 

0 1 2 

Visibility 

0.05 

0.1 

0 100 200 300 400 500 

1 



500 

Visibility 

0.5 

0 

0 50 100 150 200 

Fringe Number 

0 50 100 150 200 

Fringe Number 

2007-04-24 

37


UT = ( 9 27 21) 

RA = ( 13 46 57) 


LT = ( 1 27 21) 

Dec = ( 6 21 1) 

avIA = 188 avIB = 167 


HA = 23.02 


avBP = 153 σBP = 8 

Alt = 59.01 



Azm = 330.78 


U = 166.022 


Results: 

V = 263.539 


BY = 2007.187257 


lpass = 20 

Rejects = 171 

JD = 54169.8940 

BW = 30 


Vamp = 0.213 

λ = 2.15E-006 

range = 30 

Vps = 0.204 

σVis = 0.015 

350 

= UTDate = ( 2007 3 10) 

SeqNo = 2 

B = 311.477 Brange = 0.642 

Θ = 57.791 Θrange = 0.256 

Power 

0.15 

0.1 

0.05 

0 


Red = Signal 

Blue = Noise 

Green = Dark 



V 

0 

40 

0.05 

Number 

20 

350 

350 0 350 

U 

0 

0 1 2 

Visibility 

0.1 

0 100 200 300 400 500 

1 



500 

Visibility 

0.5 

0 

0 50 100 150 200 250 

Fringe Number 

0 50 100 150 200 250 

Fringe Number 

2007-04-24 

38


UT = ( 9 37 31) 

RA = ( 13 34 42) 


LT = ( 1 37 31) 

Dec = ( 0 35 45) 

avIA = 882 avIB = 733 


HA = 23.40 


avBP = 152 σBP = 8 

Alt = 55.32 



Azm = 343.98 


U = 151.579 


Results: 

V = 251.243 


BY = 2007.187276 


lpass = 20 

Rejects = 127 

JD = 54169.9011 

BW = 30 


Vamp = 0.152 

λ = 2.15E-006 

range = 30 

Vps = 0.203 

σVis = 0.020 

350 

= UTDate = ( 2007 3 10) 

SeqNo = 2 

B = 293.430 Brange = 0.859 

Θ = 58.898 Θrange = 0.285 

Power 

0.15 

0.1 

0.05 

0 


Red = Signal 

Blue = Noise 

Green = Dark 



V 

0 

40 

0.05 

Number 

20 

350 

350 0 350 

U 

0 

0 1 2 

Visibility 

0.1 

0 100 200 300 400 500 

1 



500 

Visibility 

0.5 

0 

0 50 100 150 200 

Fringe Number 

0 50 100 150 200 

Fringe Number 

2007-04-24 

39


UT = ( 9 52 3) 

RA = ( 13 46 57) 


LT = ( 1 52 3) 

Dec = ( 6 21 1) 

avIA = 190 avIB = 165 


HA = 23.44 


avBP = 154 σBP = 8 

Alt = 61.04 


Freq0 = 155 DithStep = −0.333 

Azm = 342.42 


U = 150.009 


Results: 

V = 265.430 


BY = 2007.187304 


lpass = 20 

Rejects = 155 

JD = 54169.9111 

BW = 30 


Vamp = 0.198 

λ = 2.15E-006 

range = 30 

Vps = 0.191 

σVis = 0.023 

350 

= UTDate = ( 2007 3 10) 

SeqNo = 3 

B = 304.891 Brange = 0.683 

Θ = 60.527 Θrange = 0.296 

Power 

0.15 

0.1 

0.05 

0 


Red = Signal 

Blue = Noise 

Green = Dark 



V 

0 

40 

0.05 

Number 

20 

350 

350 0 350 

U 

0 

0 1 2 

Visibility 

0.1 

0 100 200 300 400 500 

1 



500 

Visibility 

0.5 

0 

0 50 100 150 200 250 

Fringe Number 

0 50 100 150 200 250 

Fringe Number 

2007-04-24 

40


UT = ( 10 5 23) 

RA = ( 13 34 42) 


LT = ( 2 5 23) 

Dec = ( 0 35 45) 

avIA = 827 avIB = 716 


HA = 23.86 


avBP = 153 σBP = 9 

Alt = 56.31 



Azm = 356.29 


U = 131.607 


Results: 

V = 251.422 


BY = 2007.187329 


lpass = 20 

Rejects = 154 

JD = 54169.9204 

BW = 30 


Vamp = 0.162 

λ = 2.15E-006 

range = 30 

Vps = 0.210 

σVis = 0.016 

350 

= UTDate = ( 2007 3 10) 

SeqNo = 3 

B = 283.789 Brange = 0.859 

Θ = 62.371 Θrange = 0.338 

Power 

0.15 

0.1 

0.05 

0 


Red = Signal 

Blue = Noise 

Green = Dark 



V 

0 

40 

0.05 

Number 

20 

350 

350 0 350 

U 

0 

0 1 2 

Visibility 

0.1 

0 100 200 300 400 500 

1 



500 

Visibility 

0.5 

0 

0 50 100 150 200 250 

Fringe Number 

0 50 100 150 200 250 

Fringe Number 

2007-04-24 

41


UT = ( 10 16 13) 

RA = ( 13 46 57) 


LT = ( 2 16 13) 

Dec = ( 6 21 1) 

avIA = 157 avIB = 135 


HA = 23.84 


avBP = 153 σBP = 8 

Alt = 62.03 



Azm = 354.91 


U = 132.645 


Results: 

V = 267.085 


BY = 2007.187349 


lpass = 20 

Rejects = 161 

JD = 54169.9279 

BW = 30 


Vamp = 0.211 

λ = 2.15E-006 

range = 30 

Vps = 0.202 

σVis = 0.019 

350 

= UTDate = ( 2007 3 10) 

SeqNo = 4 

B = 298.215 Brange = 0.689 

Θ = 63.590 Θrange = 0.336 

Power 

0.15 

0.1 

0.05 

0 


Red = Signal 

Blue = Noise 

Green = Dark 



V 

0 

350 

350 0 350 

U 

Number 

60 

40 

20 

0 

0 1 2 

Visibility 

0.05 

0.1 

0 100 200 300 400 500 

1 



500 

Visibility 

0.5 

0 

0 50 100 150 200 250 

Fringe Number 

0 50 100 150 200 250 

Fringe Number 

2007-04-24 

42


UT = ( 10 26 26) 

RA = ( 13 34 42) 


LT = ( 2 26 26) 

Dec = ( 0 35 45) 

avIA = 633 avIB = 559 


HA = 0.21 


avBP = 153 σBP = 8 

Alt = 56.24 



Azm = 5.58 


U = 115.595 


Results: 

V = 251.538 


BY = 2007.187369 


lpass = 20 

Rejects = 118 

JD = 54169.9350 

BW = 30 


Vamp = 0.153 

λ = 2.15E-006 

range = 30 

Vps = 0.203 

σVis = 0.010 

350 

= UTDate = ( 2007 3 10) 

SeqNo = 4 

B = 276.832 Brange = 0.659 

Θ = 65.319 Θrange = 0.302 

Power 

0.15 

0.1 

0.05 

0 


Red = Signal 

Blue = Noise 

Green = Dark 



V 

0 

350 

350 0 350 

U 

Number 

60 

40 

20 

0 

0 1 2 

Visibility 

0.05 

0.1 

0 100 200 300 400 500 

1 



500 

Visibility 

0.5 

0 

0 50 100 150 200 

Fringe Number 

0 50 100 150 200 

Fringe Number 

2007-04-24 

43


UT = ( 10 36 50) 

RA = ( 13 46 57) 


LT = ( 2 36 50) 

Dec = ( 6 21 1) 

avIA = 145 avIB = 121 

LST = 13.967 

LSTrange = 0.0417 ΓA = 0.999 ΓB = 0.953 

HA = 0.18 


avBP = 153 σBP = 8 

Alt = 62.00 



Azm = 5.87 


U = 116.654 


Results: 

V = 268.329 


BY = 2007.187389 


lpass = 20 

Rejects = 171 

JD = 54169.9422 

BW = 30 


Vamp = 0.209 

λ = 2.15E-006 

range = 30 

Vps = 0.185 

σVis = 0.017 

350 

= UTDate = ( 2007 3 10) 

SeqNo = 5 

B = 292.596 Brange = 0.666 

Θ = 66.504 Θrange = 0.369 

Power 

0.15 

0.1 

0.05 

0 


Red = Signal 

Blue = Noise 

Green = Dark 



V 

0 

350 

350 0 350 

U 

Number 

60 

40 

20 

0 

0 1 2 

Visibility 

0.05 

0.1 

0 100 200 300 400 500 

1 



500 

Visibility 

0.5 

0 

0 50 100 150 200 250 300 

Fringe Number 

0 50 100 150 200 250 300 

Fringe Number 

2007-04-24 

44


UT = ( 10 48 25) 

RA = ( 13 34 42) 


LT = ( 2 48 25) 

Dec = ( 0 35 45) 

avIA = 533 avIB = 461 


HA = 0.58 


avBP = 152 σBP = 7 

Alt = 55.39 



Azm = 15.51 


U = 97.014 


Results: 

V = 251.647 


BY = 2007.187411 


lpass = 20 

Rejects = 132 

JD = 54169.9503 

BW = 30 


Vamp = 0.145 

λ = 2.15E-006 

range = 30 

Vps = 0.195 

σVis = 0.013 

350 

= UTDate = ( 2007 3 10) 

SeqNo = 5 

B = 269.707 Brange = 0.751 

Θ = 68.919 Θrange = 0.420 

Power 

0.15 

0.1 

0.05 

0 


Red = Signal 

Blue = Noise 

Green = Dark 



V 

0 

350 

350 0 350 

U 

Number 

60 

40 

20 

0 

0 1 2 

Visibility 

0.05 

0.1 

0 100 200 300 400 500 

1 



500 

Visibility 

0.5 

0 

0 50 100 150 200 

Fringe Number 

0 50 100 150 200 

Fringe Number 

2007-04-24 

45


UT = ( 10 58 2) 

RA = ( 13 46 57) 


LT = ( 2 58 2) 

Dec = ( 6 21 1) 

avIA = 113 avIB = 94 


HA = 0.55 


avBP = 154 σBP = 8 

Alt = 61.10 



Azm = 17.07 


U = 98.801 


Results: 

V = 269.461 


BY = 2007.187429 


lpass = 20 

Rejects = 225 

JD = 54169.9570 

BW = 30 


Vamp = 0.204 

λ = 2.15E-006 

range = 30 

Vps = 0.132 

σVis = 0.021 

350 

= UTDate = ( 2007 3 10) 

SeqNo = 6 

B = 287.013 Brange = 0.735 

Θ = 69.865 Θrange = 0.483 

Power 

0.35 

0.3 

0.25 

0.2 

0.15 

0.1 

0.05 


Red = Signal 

Blue = Noise 

Green = Dark 



V 

0 

60 

0 

350 

350 0 350 

U 

Number 

40 

20 

0 

0 1 2 

Visibility 

0.05 

0.1 

0 100 200 300 400 500 

1 



500 

Visibility 

0.5 

0 

0 50 100 150 200 250 300 350 

Fringe Number 

0 50 100 150 200 250 300 350 

Fringe Number 

2007-04-24 

46


UT = ( 11 13 51) 

RA = ( 13 34 42) 


LT = ( 3 13 51) 

Dec = ( 0 35 45) 

avIA = 422 avIB = 380 


HA = 1.02 


avBP = 154 σBP = 7 

Alt = 53.47 



Azm = 26.19 


U = 74.444 


Results: 

V = 251.748 


BY = 2007.187459 


lpass = 20 

Rejects = 229 

JD = 54169.9679 

BW = 30 


Vamp = 0.129 

λ = 2.15E-006 

range = 30 

Vps = 0.176 

σVis = 0.023 

350 

= UTDate = ( 2007 3 10) 

SeqNo = 6 

B = 262.537 Brange = 0.746 

Θ = 73.528 Θrange = 0.559 

Power 

0.15 

0.1 

0.05 

0 


Red = Signal 

Blue = Noise 

Green = Dark 



V 

0 

100 

0.05 

Number 

50 

350 

350 0 350 

U 

0 

0 1 2 

Visibility 

0.1 

0 100 200 300 400 500 

1 



500 

Visibility 

0.5 

0 

0 50 100 150 200 250 300 350 

Fringe Number 

0 50 100 150 200 250 300 350 

Fringe Number 

2007-04-24 

47

0.4 


UT = ( 11 24 39) 

RA = ( 13 46 57) 


LT = ( 3 24 39) 

Dec = ( 6 21 1) 

avIA = 84 

avIB = 69 


HA = 0.99 


avBP = 153 σBP = 8 

Alt = 58.91 



Azm = 29.61 


U = 75.702 


Results: 

V = 270.586 


BY = 2007.18748 


lpass = 20 

Rejects = 255 

JD = 54169.9755 

BW = 30 


Vamp = 0.207 

λ = 2.15E-006 

range = 30 

Vps = 0.143 

σVis = 0.023 

350 

= UTDate = ( 2007 3 10) 

SeqNo = 7 

B = 280.988 Brange = 0.611 

Power 

0.3 

0.2 

0.1 


Red = Signal 

Blue = Noise 

Green = Dark 



Θ = 74.371 Θrange = 0.528 

V 

0 

350 

350 0 350 

U 

Number 

60 

40 

20 

0 

0 1 2 

Visibility 

0 

0.1 

0 100 200 300 400 500 

1 



500 

Visibility 

0.5 

0 

0 50 100 150 200 250 300 350 

Fringe Number 

0 50 100 150 200 250 300 350 

Fringe Number 

2007-04-24 

48

0.4 


0.3 

Red = Signal 

Blue = Noise 

Green = Dark 



0.2 

Power 

0.1 

0 

Visibility 

0.1 

0 100 200 300 400 500 

Reference cart 

change position 


500 

0 

0 50 100 150 200 250 300 350 

Fringe Number 

0.8 

Weak power spectrum / 

Bad fringe tracking 

VISIBILITY 

0.6 

0.4 

0.2 

2007-04-24 

0 

2007.1872 2007.187275 2007.18735 2007.187425 2007.1875 

EPOCH 

49

HD 118098- “Troubling fit” 

• Over the two nights this 

star was observed there 

were 

Vibrations in lab 

Observer errors 

• Combined data sets 

reduced in both reduceir 

and VisUV Calc show 

these systematic 

problems. 

Visibility 

Visibility 

1 

0.8 

0.6 

0.4 

0.2 

0 

1 

0.8 

0.6 

0.4 

0.2 



mDiamL= 

0.826 

σmDiamL= 

0.063 

σresL = 0.040 

wmDiamL= 

0.827 

Visibility 

σwmDiamL= 

0.062 

0 50 100 150 200 250 300 350 


Visibility 

1 

0.8 

0.6 

0.4 

0.2 

0 

1 

0.8 

0.6 

0.4 

0.2 



mDiamL= 

0.880 

σmDiamL= 

0.087 

σresL = 0.057 

wmDiamL= 

0.862 

σwmDiamL= 

0.070 

0 50 100 150 200 250 300 350 


0 

0 

2007-04-24 

120 125 130 135 140 145 150 


120 125 130 135 140 145 150 


50

Procyon: HD 61421 

NSII 

CHARA 



1 

mDiamU= 

5.465 

Aufdenberg, J., Ludwig, H.,, Kervella, P. (2005) 

0.8 

σmDiamU= 

0.045 

1 

0.8 

mDiamL= 

5.445 

σmDiamL= 

0.045 

0.6 

θ LD = 5.404 +/- 0.031 mas 

Visibility 

0.4 

σresU = 0.003 

wmDiamU= 

5.463 

σwmDiamU= 

0.045 

Visibility 

0.6 

0.4 

σresL = 0.003 

wmDiamL= 

5.443 

σwmDiamL= 

0.045 

0.2 

0.2 

0 

0 

0 50 100 150 200 250 300 350 


0 50 100 150 200 250 300 350 




0.05 

0.05 

Visibility 

Visibility 

0 

0 

2007-04-24 

106 107 108 109 110 111 112 113 114 115 116 


106 108 110 112 114 116 


51

A, F, and G Dwarf Diameters 

Sp.Type Theta(LD) Error %Error #Obs Min. Vis 

(mas) (mas) good(all) 

2007-04-24 

A1V 1.094 0.024 2.2 7(7) 0.45 

A3V 0.862 0.070 8.1 5(11) 0.56 

A3V 0.835 0.046 5.5 7(7) 0.60 

A4V 1.332 0.018 1.4 8(10) 0.30 

F0V 0.844 0.058 6.9 4(6) 0.60 

F5IV 5.443 0.045 0.8 2(2) 0.05 

F5IV 1.362 0.014 1.0 4(4) 0.22 

F7V 1.194 0.007 0.6 2(4) 0.45 

F7V** 0.893 0.086 9.6 35 0.44 

F8V* 1.463 0.019 1.3 6(6) 0.30 

F9V 1.151 0.016 1.4 4(5) 0.35 

G0V 1.022 0.035 3.4 4(5) 0.40 

G0V 1.248 0.046 3.7 7(7) 0.25 

G0V* 1.057 0.049 4.6 11(11) 0.40 

G0V** 0.812 0.082 10.1 3(3) 0.56 

G5V** 0.746 0.038 5.1 40 0.61 

G6IV** 0.654 0.053 8.1 20 0.64 

G8V 1.099 0.016 1.5 5(5) 0.4 

52

Sample Range 

Baines 

Boyajian 

More to be added!!! 

2007-04-24 

53

Anticipated Results 

• Temperatures 

New calibration of T eff scale for A, F, and G dwarfs 

• New calibration of photometric relations 

Barnes-Evans: surface brightness vs. color relation 

IRFM: Ratio of flux’s: Total / Infrared -> T eff 

• Existing diameter measurements 

Comparing results to diameters from eclipsing binaries, lunar occultations, 

speckle and long-baseline interferometry 

Compile an up-to-date table of Dwarf diameter measurements 

• Metallicity 

Is there a radius VS metallicity relation in A, F and G stars 

• Evolutionary status of stars 

Linear diameters + models = age 

• By-Products 

Discover new binaries 

The results of this sample can in turn be used to provide a new resource of 

calibrators for other projects 

2007-04-24 

54

Tentative Timeline 

• Collect data, reduce data, calibrate data, 

analyze data, write thesis, get job, 

graduate: Spring 2009 

• Thank you for your interference! 

2007-04-24 

55

Sizing up the Stars - Department of Physics and Astronomy ...

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