Delta Sco
Periastron campaign 2011

July 22, 2011 update


Delta Scorpii (HD 143275) is a bright Be binary system with a highly eccentric elliptical orbit and an orbital period of almost 11 years.
Position (2000): a = 16h 00m 20.0s, d = -22 37' 18".

The periastron time is predicted for the first days of July 2011 (July 6, +/-2). High quality spectroscopic radial velocity (RV) observations are very encouraged during 2011 year - see Anatoly Miroshnichenko webpage's: http://www.uncg.edu/~a_mirosh/Delta_Sco/.  Amateur spectroscopic RV data can substantially improve the uncertainties of the predicted date of the periastron, but high precision is required, better then 10 km/s. The radial velocity expected variation is about 40 km/s during a period of +/-1 month relative to the date of periastron.

Example of usefull amateur instruments for the campaign are Lhires III (2400 l/mm configuration - typical resolution power of R=15000) and echelle spectrographe eShel (precise ThorAr spectral calibration, R=11000). Extensive information and recommendations about spectroscopic observations of Delta Sco are given in Anatoly Miroshnichenko's pages. See also http://www.stsci.de/convento/pdf/deltaSco2011.pdf (ConVento group page).

The periastron passage can also produce high interaction between the secondary and the circumstellar matter of the primary, so a Ha morphologie spectral profile survey is also welcome.

The present page is a compilation of amateur Delta Scopii spectra specially dedicated to the present 2011 periastron campaign. The data are available to professional community for anaysis and publications. See also the Be stars database BeSS for an enlarged compilation (pro/am) of Delta Sco spectra (many years of observation), and remember to submit your spectra to BeSS.

About recent Delta Scorpii orbit and periastron time prediction see the reference (C. Tycner & all paper): http://arxiv.org/abs/1101.5152


LOG OF OBSERVATIONS
 

#

Date (DD/MM/YYYY)

Observer

Instrument

Exposure

Resolution
Range (nm)
fits files
Heliocentric velocity not corrected
dat files
Heliocentric velocity corrected

Notes

1

10.245/01/2011

C. Buil

C11 + eShel

11 x 300 s

11000

430-710
_deltasco_20110110_245_buil.fit
_deltasco_20110110_245_buil.dat

 1

 2

20.232/01/2011

C. Buil

C11 + eShel

9 x 300 s

11000

430-710

_deltasco_20110120_232_buil.fit

_deltasco_20110120_232_buil.dat

 1

 3

23.225/01/2011

C. Buil

C11 + eShel

12 x 300 s

11000

430-710

_deltasco_20110123_225_buil.fit

 _deltasco_20110123_225_buil.dat

 1

4

9.209/02/2011

C. Buil

C11 + eShel

17 x 180 s

11000

430-710

_deltasco_20110209_209_buil.fit

_deltasco_20110209_209_buil.dat

1

5

6.196/03/2011

C. Buil

C11 + eShel

17 x 180 s

11000

430-710

_deltasco_20110306_196_buil.fit

_deltasco_20110306_196_buil.dat

1

6

25.100/03/2011

C. Buil

C11 + eShel

16 x 300 s

11000

430-710

_deltasco_20110325_100_buil.fit

_deltasco_20110325_100_buil.dat

1

7

16.050/04/2011

C. Buil

C11 + eShel

11 x 300 s

11000

430-710

_deltasco_20110416_050_buil.fit

_deltasco_20110416_050_buil.dat

1

8

16.080/04/2011

J. Ribeiro

C14 + Lhires III (2400)

3740 s

16000

458 - 483

_deltasco_20110416_080_ribeiro.fit

_deltasco_20110416_080_ribeiro.dat

1

9

28.059/04/2011

C. Buil

C11 + eShel

15 x 180 s

11000

430-710

_deltasco_20110428_059_buil.fit

_deltasco_20110428_059_buil.dat

1

10

3.991/05/2011

C. Buil

C11 + eShel

15 x 180 s

11000

430-710

_deltasco_20110503_991_buil.fit

_deltasco_20110503_991_buil.dat

1

11

11.011/05/2011

C. Buil

C11 + eShel

10 x 300 s

11000

430-710

_deltasco_20110511_011_buil.fit

_deltasco_20110511_011_buil.dat

1

12

22.925/05/2011

C. Buil

C11 + eShel

7 x 300 s

11000

430-710

_deltasco_20110522_925_buil.fit

_deltasco_20110522_925_buil.dat

1

13

28.048/05/2011

C. Buil

C11 + eShel

7 x 300 s

11000

430-710

_deltasco_20110528_048_buil.fit

_deltasco_20110528_048_buil.dat

1

14

28.878/05/2011

C. Buil

C11 + eShel

9 x 300 s

11000

430-710

_deltasco_20110528_878_buil.fit

_deltasco_20110528_878_buil.dat

1

15

13.960/06/2011

C. Buil

C11 + Lhires III (2400)

6 x 180 s

10000

458-473

_deltasco_20110613_960_buil.fit

_deltasco_20110613_960_buil.dat

1

16

14.919/06/2011

C. Buil

C11 + eShel

11 x 180 s

11000

430-710

_deltasco_20110614_919_buil.fit

_deltasco_20110614_919_buil.dat

1

17

15.931/06/2011

C. Buil

C11 + eShel

13 x 180 s

11000

430-710

_deltasco_20110615_931_buil.fit

_deltasco_20110615_931_buil.dat

1

18

18.896/06/2011

C. Buil

C11 + eShel

8 x 180 s

11000

430-710

_deltasco_20110618_896_buil.fit

_deltasco_20110618_896_buil.dat

1

19

26.859/06/2011

C. Buil

C11 + eShel

7 x 240 s

11000

430-710

_deltasco_20110626_859_buil.fit

_deltasco_20110626_859_buil.dat

1

20

1.874/07/2011

C. Buil

C11 + eShel

10 x 240 s

11000

430-710

_deltasco_20110701_874_buil.fit

_deltasco_20110701_874_buil.dat

1

21

2.976/07/2011

C. Buil

C11 + eShel

10 x 240 s

11000

430-710

_deltasco_20110702_976_buil.fit

_deltasco_20110702_976_buil.dat

1

22

4.858/07/2011

C. Buil

C11 + eShel

8 x 240 s

11000

430-710

_deltasco_20110704_858_buil.fit

_deltasco_20110704_858_buil.dat

1

23

5.949/07/2011

C. Buil

C11 + eShel

8 x 240 s

11000

430-710

_deltasco_20110705_949_buil.fit

_deltasco_20110705_949_buil.dat

1

24

8.850/07/2011

C. Buil

C11 + eShel

16 x 150 s

11000

430-710

_deltasco_20110708_850_buil.fit

_deltasco_20110708_850_buil.dat

1

25

9.854/07/2011

C. Buil

C11 + eShel

16 x 180 s

11000

430-710

_deltasco_20110709_854_buil.fit

_deltasco_20110709_854_buil.dat

1

26

10.856/07/2011

C. Buil

C11 + eShel

7 x 180 s

11000

430-710

_deltasco_20110710_856_buil.fit

_deltasco_20110710_856_buil.dat

1

27

10.893/07/2011

C. Buil

C11 + eShel

8 x 180 s

11000

430-710

_deltasco_20110710_896_buil.fit

_deltasco_20110710_896_buil.dat

1

28

11.848/07/2011

C. Buil

C11 + eShel

16 x 240 s

11000

430-710

_deltasco_20110711_848_buil.fit

_deltasco_20110711_848_buil.dat

1

29

17.870/07/2011

C. Buil

C11 + eShel

11 x 240 s

11000

430-710

_deltasco_20110717_870_buil.fit

_deltasco_20110717_870_buil.dat

1

30

20.859/07/2011

C. Buil

C11 + eShel

16 x 180 s

11000

430-710

_deltasco_20110720_859_buil.fit

_deltasco_20110720_859_buil.dat

1

31

21.923/07/2011

C. Buil

C11 + eShel

10 x 180 s

11000

430-710

_deltasco_20110721_923_buil.fit

_deltasco_20110721_923_buil.dat

1

Note: For the .dat spectra, the telluric lines are removed and heliocentric velocity is corrected.

#

JD0 - 2450000

Rectified continuum (He II region)

Relative radial velocity
Based on minimisation of difference between current spectra and ref spectrum near 4686 A region (km/s)

Relative radial velocity
Based on gaussien fit of 4686 A line
(km/s)

Absolute radial velocity based on 4686 A line
(mean of subtraction
and gaussien fit methods)

Reference

5585.000

ref.dat

 

 

-11.46 km/s

1

5571.741

a1.dat

-4.0

-5.6

-16.26 km/s

2

5581.729

a2.dat

+0.0

-0.6

-12.06 km/s

3

5584.722

a3.dat

+2.0

+2.0

-11.76 km/s

4

5601.708

a4.dat

+2.0

+0.2

-10.36 km/s

5

5626.697

a5.dat

-5.0

-5.1

-16.51 km/s

6

5645.603

a6.dat

-4.0

-3.6

-15.26 km/s

7

5667.555

a7.dat

+2.0

+2.8

-9.06 km/s

8

5667.667

a8.dat

+3.0

+5.6

-7.16 km/s

9

5679.564

a9.dat

-10.0

-9.9

-21.41 km/s

10

5685.496

a10.dat

+0.0

+0.1

-11.41 km/s

11

5692.517

a11.dat

-5.0

+1.0

-13.46 km /s

12

5704.431

a12.dat

-7.0

-6.1

-18.01 km/s

13

5709.554

a13.dat

-9.0

-8.1

-20.01 km/s

14

5710.383

a14.dat

-10.0

-7.9

-20.41 km/s

15

5726.465

a15.dat

-13.0

-10.7

-23.31 km/s

16

5727.424

a16.dat

-16.0

-12.9

-25.91 km/s

17

5728.436

a17.dat

-17.0

-14.7

-27.31 km/s

18

5731.401

a18.dat

-31.0

-29.3

-41.61 km/s

19

5739.364

a19.dat

-28.0

-28.2

-39.56 km/s

20

5744.379

a20.dat

-35.0

-37.1

-47.51 km/s

21

5745.481

a21.dat

-35.0

-37.7

-47.81 km/s

22

5747.362

a22.dat

-36.0

-34.6

-46.76 km/s

23

5748.453

a23.dat

-37.0

-37.1

-48.51 km/s

24

5751.354

a24.dat

-22.0

-22.5

-33.71 km/s

25

5752.358

a25.dat

-25.0

-28.9

-38.41 km/s

26

5753.360

a26.dat

-32.0

-35.9

-45.42 km/s

27

5753.397

a27.dat

-38.0

-21.6

-41.26 km/s

28

5754.352

a28.dat

-32.0

-31.2

-43.01 km/s

29

5760.373

a29.dat

-23.0

-23.0

-34.46 km/s

30

5763.363

a30.dat

-14.0

-12.2

-24.56 km/s

31

5764.426

a31.dat

-16.0

-11.5

-25.22 km/s

Note: The reference spectrum is the mean of #1, #2, #3 and #4 individual spectra. Radial velocity is measured relative to the reference spectrum.
The gaussien fit center of 4686 A line on reference spectrum give position 4685.503 A (RV=-11.460 km/s relative to admited rest wavelength of 4685.682 A).


2011 STATUS



Time evolution of HeII 4686 A line - Shift of 0.05 intensity unit is applied for clarity.
 



Time evolution of Ha - Shift of 0.3 intensity unit is applied for clarity.

 

Dynamic Halpha line evolution.


Radial velocity (HeII 4686 A reference). Typical measure error is +/- 3 km/s (1-sigma) - Positive radial: object move toward observer.


SUMMARY OF 2010 ACTIVITY

 C11 telescope (D = 0.28 m) + eShel spectrographe (echelle R = 11000) - C. Buil - Castanet-Tolosan observatory.

 
Typical high resolution H
a profile at R = 25600 (date 05/07/2010). No correction by heliocentricity or waterlines. By Lothar Shanne.


LINES IDENTIFICATION


C11 telescope (D = 0.28 m) + eShel spectrographe (echelle R = 11000) - C. Buil - Castanet-Tolosan observatory.

Note: Orbital radial velocity measure from Ha profile is not easy because the high sensibility to circumstellar activity. He I lines are also variables because part of them form in a region above the photosphere, near the inner boundary of the disk. Therefore, they are affected by the densest circumstellar matter that is reflected in their changing radial velocities. A. Miroshnichenko suggest use of He II for good RV measurements. These lines form in the photosphere and are not affected by circumstellar medium. There are only two He II in the optical spectrum of Delta Sco at 4686 A (see below) and at 5411 A (very weak).

The He II l4686 A line position time stability.


Conditions for use of data in publications                                                               
Note there is no precise validation check prior to adding spectra to this table. Users should verify the quality of the spectra with the observers concerned.    
Use of these data in research publications is encouraged subject to the following conditions: The observers concerned should be contacted to confirm the particular acquisition and data reduction procedures used.


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