Mulitplicity-study of nearby B-type stars
using near-infrared data from ESO-VLT Archive

Christian Adam
Astrophysikalisches Institut und Universitätssternwarte
Friedrich-Schiller Universität Jena
Jan. 19th 2011

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 2011

1 / 22O UTLINE

1M OTIVATION

2DATA SELECTION AND REDUCTION

3DATA ANALYSIS

4R ESULTS & S UMMARY

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 20112 / 22

M OTIVATIONBASIC Q UESTIONS

1Why intermediate/high-mass stars?
principal source of heavy elements and UV-radiation
affect the physical, chemical, and morphological structure ofgalaxies (e.g Kennicutt 1998, 2005)
strong influence on star- and planet-formation in their environment(Bally et al. 2005)
and high frequency of multiplicity (But why and what is thefrequency of multiplicity?)2

Why near-infrared data?

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 2011

3 / 22

M OTIVATION(Burrows et al. 2001)
Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 2011

3 / 22

M OTIVATIONG OALS EARCH FOR UNKNOWN M ULTIPLICITY OF B- STARS INESO/VLT-NAC O A RCHIVE DATA USING D IRECT I MAGING
increase the data sample size −→ improve statistics
estimate frequency of multiple systems among all B-stars“improve understanding of formation and evolution of high-massstars and multiple systems”

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 2011

3 / 22

1

M OTIVATION

2DATA SELECTION AND REDUCTION

3DATA ANALYSIS

4R ESULTS & S UMMARY

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 2011

4 / 22

T HE S AMPLEINFORMATION

Infosposition, αJ2000 and δJ2000proper motion, µα and µδ
magnitudes U, B, V, R, I, J, H and K, and spectral type B
Parallax πsmall uncertainties in π =⇒ more precise magnitudes
catalogs: Simbad, Vizier (Hipparcos, 2Mass)

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 2011

5 / 22

T HE S AMPLESELECTION

π = 1mas =⇒ volume-limited sample of objects d . 1 kpc
1st: search in Simbad and Hipparcos: 8146 B-stars
2nd: limit sample by accuracy of Parallax
SpTyp#π − 1σπ ≥ 1 mas

π − 2σπ ≥ 1 mas

π − 3σπ ≥ 1 mas

B

8146

5967

3956

2600

3rd: search in ESO-VLT/NaCo archive:

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 2011

6 / 22

T HE S AMPLESELECTION

π = 1mas =⇒ volume-limited sample of objects d . 1 kpc
1st: search in Simbad and Hipparcos: 8146 B-stars
2nd: limit sample by accuracy of Parallax
SpTyp#π − 1σπ ≥ 1 mas

π − 2σπ ≥ 1 mas

π − 3σπ ≥ 1 mas

B

8146

5967

3956

2600

3rd: search in ESO-VLT/NaCo archive:

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 2011

6 / 22

T HE S AMPLESELECTION

π = 1mas =⇒ volume-limited sample of objects d . 1 kpc
1st: search in Simbad and Hipparcos: 8146 B-stars
2nd: limit sample by accuracy of Parallax
SpTyp#π − 1σπ ≥ 1 mas

π − 2σπ ≥ 1 mas

π − 3σπ ≥ 1 mas

B8146

5967

3956

2600

3rd: search in ESO-VLT/NaCo archive: 231 availible objects

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 2011

6 / 22

T HE R EDUCTION

standard reduction for all data
conicap-pipline for dark- and flat-field reduction (Devillard 1997)
jitter algorithm used for science-data reduction

IMGSCI =RAWSCI − DARKSCIFLAT − DARKFLAT

Shift+Add −→ reduced science image

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 20117 / 22

1

M OTIVATION

2DATA SELECTION AND REDUCTION

3DATA ANALYSIS

4R ESULTS & S UMMARY

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 20118 / 22

P OSITION OF O BJECTSM EASURMENTSoftware: MIDAS, Sextractor, Gaia, IDL
Howto measure the position
12

1Center of fluxmaximum of PSF1 -fitting (2D-Gaussian-fit) <– used here

PSF... Point-Spread-Function

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 2011

9 / 22

P OSITION OF O BJECTSPSF S UBTRACTION

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 201110 / 22

P OSITION OF O BJECTSPSF S UBTRACTION

superposition of Psf =⇒ shift in pixelposition
solution: substract Psf from Image
12symmetric model Psf
measured (”real”) Psf

result: corrected pixelposition of objects
Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 201110 / 22

P OSITION OF O BJECTSPSF S UBTRACTION

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 201110 / 22

P OSITION OF O BJECTSPSF S UBTRACTION

xi , yi Position [pixel] −→ Separation sep∗ [pixel] & Position Angle pa∗ [deg]sep∗ =∗p(xi − xj )2 + (yi − yj )2

pa = arctan

Christian Adam (AIU-Jena)(yi − yj )(xi − xj )Mulitplicity of B-stars∀ i 6= jJan. 19th 201110 / 22

C ALIBRATIONS TANDARD C ALIBRATION P ROCEDURE1Binary with known separation and position angle

2

calculate theoretical sep and position angle for observing-date oftarget3

measure sep and pos.-angle of calib.-bin. for target night=⇒ Pixel-scale and rotation angle for target

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 201111 / 22

C ALIBRATIONS TANDARD C ALIBRATION P ROCEDURE

1

Binary with known separation and position angle

2

calculate theoretical sep and position angle for observing-date oftarget3

measure sep and pos.-angle of calib.-bin. for target night=⇒ Pixel-scale and rotation angle for target

not applied, due to limited time of thesis

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 201111 / 22

C OMMON PROPER - MOTION PAIR ANALYSISC OMPANION SEARCH WITH DIRECT- IMAGING
If cc is a is a comoving object
host−starcc

host−starN

NE

first epochhost−star

const. sep. and pacc

ecxept changes due toorbital motionEsecond epoch
If cc is a background object

cccc

sep. and pa 6= const.
host−starNE

first epoch

Christian Adam (AIU-Jena)

Nhigh probability ofbg-object

Esecond epoch

Mulitplicity of B-stars

Jan. 19th 201112 / 22

C OMMON PROPER - MOTION PAIR ANALYSISBACKGROUND -T HESIS

apparent motion on sky as result of superposition of:
12

proper motion µra , µdec → ∆αpm , ∆δpm
annual motion of earth around the sun → ∆απ , ∆δπ
∆αbg
∆δbg

= ∆αpm + ∆απ= ∆δpm + ∆δπ

Christian Adam (AIU-Jena)q2∆α2bg + ∆δbg

sepbg

= ρmeas +pabg= Φmeas + arctan=⇒Mulitplicity of B-stars∆δbg∆αbgJan. 19th 201113 / 22

C OMMON PROPER - MOTION PAIR ANALYSISO RBITAL -M OTION E STIMATIONra3(M∗ + MP )maximum change in sep for circularedge-on orbit (left)P∝

maximum change in pa for circularpole-on orbit (right)=⇒∆ρ = 4 · ρmax ·assuming a ≈ ρmax =⇒ P from 3rd.
Keplers law=⇒∆Φ = 360 ·Christian Adam (AIU-Jena)

Mulitplicity of B-stars

∆t
P

∆t
P

Jan. 19th 201114 / 22

C OMMON PROPER - MOTION PAIR ANALYSISE XAMPLE : HIP 60449

D = 125 pc
SpType: B8/9V≈ 3.7M (Lang,1992)a ≈ 88 AU, P ≈425 yr
MJD
53413.28742
54510.35386

Sep [00 ]0.6961±0.0048
0.7165±0.0031

Christian Adam (AIU-Jena)

Sepbg [00 ]0.7885±0.0043
-σSep
14.3
-

Mulitplicity of B-stars

P.A. [◦ ]319.5±0.3
318.5±0.2

P.A.bg [◦ ]310.6±0.2
-

σP.A.
25.6
-

Jan. 19th 201114 / 22

M ASS -AGE -D ETERMINATIONAGEBASIC I DEA
Age of system and ∆ m =⇒ Mass of companion candidate fromevolutionary tracks, e.g. Baraffe et al. 1998, 20021

usefull models, e.g. Schaller et al. 1992, Claret 2007 or Bertelli etal. 2009: Lbol , Teff =⇒ mass and age of host-star

2Teff : from spectral type of star (Lang, 1992)

3

Lbol : J, H, K magnitudes from 2MASS and plx, Vmag fromHipparcos

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 201115 / 22

M ASS -AGE -D ETERMINATION
M ASS

Lbol : J, H, K magnitudes from 2MASS and plx, Vmag from Hipparcos(J − H)mess − (J − H)0cjv − chvr− AV
MV = mV − 5 log
10pc
AV =

wherecjv =AJAH= 0.1825, chv == 0.282
AVAV

Mbol = MV + B.C.
Lbol = 10−0,4(Mbol −Mbol,)whereMbol,= 4.84mag

Lbol , Teff in model =⇒ Age of Host-star =⇒ with ∆m and Mabs,host :Mass of companion candidate from e.g. Baraffe et al. 2002, 1998

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 201115 / 22

1

M OTIVATION

2DATA SELECTION AND REDUCTION

3DATA ANALYSIS

4R ESULTS & S UMMARY

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 201116 / 22

R ESULTSOVERVIEW

231 B-stars in ESO/VLT-NaCo archive
81 Stars with possible companion candidate(s)34 : 2+ epochs
9: unknown⇓

25: known but
5: newtriple/quadsystems

5 : high prob. cc’s
4 : medium prob. cc’s

Christian Adam (AIU-Jena)

47: 1 epoch
20: unknown⇓27: known

future work
new obs., other sources

Mulitplicity of B-stars

Jan. 19th 201117 / 22

R ESULTS
E XAMPLE : HIP 16511

Epoche2005-01-06
2005-11-26
2007-09-27

PS [mas/pixel]
13.289±0.033
13.192±0.062
27.085±0.152

Christian Adam (AIU-Jena)Φ∗ [◦ ]
-0.220±0.025-0.425±0.040-0.239±0.074

Mulitplicity of B-stars

Jan. 19th 201118 / 22

R ESULTS
E XAMPLE : HIP 16511

π = 9.18±0.87 mas ≈ 110 pc
B9IV: ≈ 2.5 M , 15 − 40 Myr
MK = 0.67 mag , ∆m ≈3.6 magsepproj. ≈ 0.15 00 ≡ 17 AU→ 0.6 M (Baraffe et al.
1998, 2002)

MJD
53376.04926
53700.13878
54370.32211

Sep [00 ]0.1445±0.0020
0.1526±0.0011
0.1794±0.0027

Christian Adam (AIU-Jena)

Epoche2005-01-06
2005-11-26
2007-09-27

Sepbg [00 ]0.3225±0.0045
0.2738±0.0041-

σSep
35.928.7-

Mulitplicity of B-stars

PS [mas/pixel]
13.289±0.033
13.192±0.062
27.085±0.152

P.A. [◦ ]112.4±0.5112.8±0.2110.8±0.6Φ∗ [◦ ]
-0.220±0.025-0.425±0.040-0.239±0.074

P.A.bg [◦ ]128.1±0.7
124.5±0.7-

σP.A.
18.016.0-

Jan. 19th 201118 / 22

R ESULTS
E XAMPLE : HIP 45344

Epoche2004-12-10
2008-02-15

PS [mas/pixel]
27.079±0.091
27.179±0.088

Christian Adam (AIU-Jena)Φ∗ [◦ ]
0.004±0.021-0.200±0.022Mulitplicity of B-stars

Jan. 19th 201119 / 22

R ESULTS
E XAMPLE : HIP 45344

π = 5.86±0.54 mas ≈ 170 pc
B4V: ≈ 4 M , ≈ 16 Myr
MK = −0.56 mag, ∆m1 ≈3.5 mag, ∆m2 ≈ 5.4 mag
sepproj. ≈ 5.9 00 ≡ 1000 AU→ M1 ≈ 1.1 M , M2 ≈0.3 M (Baraffe et al. 1998,2002)

MJD
53349.37686
54511.15795

Sep [00 ]5.8965±0.0200
5.9087±0.0197

Christian Adam (AIU-Jena)

Sepbg [00 ]5.9272±0.0203
-σSep
1.1-

Mulitplicity of B-stars

P.A. [◦ ]13.6±0.0
12.8±0.1

P.A.bg [◦ ]12.0±0.1-σP.A.
20.4-

Jan. 19th 201119 / 22

R ESULTS
E XAMPLE : HIP 45314

Epoche2004-12-16
2008-02-15

PS [mas/pixel]
27.038±0.088
27.182±0.114

Christian Adam (AIU-Jena)Φ∗ [◦ ]
0.112±0.053-0.178±0.025

Mulitplicity of B-stars

Jan. 19th 201120 / 22

R ESULTS
E XAMPLE : HIP 45314

susp. variable,∆mvar = 0.05 mag (Kukarkin
et al. 1981)
π = 6.26±0.55 mas ≈ 160 pc
B6IV: ≈ 3.2 M , ≈ 3 − 19 Myr
MK = 0.11 mag, ∆m ≈6.3 magsepproj. ≈ 2.7 00 ≡ 430 AU→ M ≈ 0.05 − 0.5 M(Baraffe et al. 1998, 2002)
MJD
53355.36407
54511.14395

Sep [00 ]2.7214±0.0090
2.7394±0.0118

Christian Adam (AIU-Jena)

Sepbg [00 ]2.8076±0.0124-Epoche2004-12-16
2008-02-15

σSep
5.6-

Mulitplicity of B-stars

PS [mas/pixel]
27.038±0.088
27.182±0.114

P.A. [◦ ]337.1±0.1
336.1±0.1Φ∗ [◦ ]
0.112±0.053-0.178±0.025

P.A.bg [◦ ]335.1±0.1
-

σP.A.
21.3
-

Jan. 19th 201120 / 22

S UMMARY

81/231 with companion candidate: ≈ 35%
61/81 are known (52 + 9 new (here)): ≈ 75%Brown Dwarf candidate around HIP45314 A ??

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 201121 / 22

S UMMARYF REQUENCY OF M ULTIPLE S YSTEMS(sub)stellar obj. with orbital periods from 102 − 104 yr in NaCo-Range (≈ 0.100 − ≈ 1300 )44/164 ≈ 27% with samemass-(period)-range like sample(81)
1=⇒ 27% of 47 1 epoch targets:
13 multiples in range

2=⇒ 73% of 231 multiple: 169multiples from SB’s to long
period3=⇒ ≈ 75% of all B-stars aremultiple ???

=⇒ To be continued ...

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 201121 / 22

E ND OF THE TALK

Thank you for your attention

Christian Adam (AIU-Jena)

Mulitplicity of B-stars

Jan. 19th 201122 / 22