J/MNRAS/304/733 Beta Pictoris 1994-96 (Petterson+, 1999)
Beta Pictoris: the variable CaII H & K absorptions 1994-1996
Petterson O.K.L., Tobin W.
<Mon. Not. R. Astron. Soc., 304, 733 (1999)>
=1999MNRAS.304..733P 1999MNRAS.304..733P (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Spectroscopy
Keywords: line: profiles - circumstellar matter -
stars: individual: beta Pictoris
Abstract
We present high-resolution spectroscopy of the variable CaII H & K
absorptions in the star Beta Pictoris. 313 spectra were obtained on 53
nights between 1994 November and 1996 December in order to
characterize the lines' behaviour and to test the Falling Evaporating
Bodies (FEB) scenario. Near-continuous absorption activity was seen,
including blue-shifted features, one of which rivalled the strength of
that reported in 1997 June by Crawford et al. (1998MNRAS.294L..31C 1998MNRAS.294L..31C).
Redshifted features at ∼5-20km/s were present until the end of 1995
and are evocative of a year-long stream of infalling bodies with
typically 4-5 objects in the line of sight. At higher velocities,
features were shorter lived and generally broader and shallower. These
correlations also apply to blue-shifted features. On 1995 June 9 we
detected a probably narrow, short-lived feature at a redshift of
∼130km/s. The FEB models predict that the strength of the H line may
exceed the K line value as a body tracks across the stellar disc, but
we have no convincing observation of this, though we did observe some
events where the H & K absorptions evolved differently.
Objects:
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RA (2000) DE Designation(s)
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05 47 17.0 -51 04 04 beta Pic = HD 39060
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 88 696 *Gaussian fits to observed variable
Ca II absorptions.
table2.ps 83 4263 PostScript version table2
fig/* . 3 Figures 1 to 53 in 3 postscript files
refs.dat 17 705 Reference spectra
94nov19.dat 52 1410 Spectra obtained on 19 Nov 1994
94nov21.dat 52 705 Spectra obtained on 21 Nov 1994
94nov22.dat 52 2111 Spectra obtained on 22 Nov 1994
94nov23.dat 52 2808 Spectra obtained on 23 Nov 1994
94nov24.dat 52 2814 Spectra obtained on 24 Nov 1994
94nov26.dat 52 2112 Spectra obtained on 26 Nov 1994
94nov27.dat 52 351 Spectra obtained on 27 Nov 1994
95apr19.dat 52 702 Spectra obtained on 19 Apr 1995
95aug01.dat 52 2464 Spectra obtained on 01 Aug 1995
95dec18.dat 52 2115 Spectra obtained on 18 Dec 1995
95dec19.dat 52 1764 Spectra obtained on 19 Dec 1995
95jul27.dat 52 1761 Spectra obtained on 27 Jul 1995
95jul28.dat 52 2466 Spectra obtained on 28 Jul 1995
95jul29.dat 52 2465 Spectra obtained on 29 Jul 1995
95jul30.dat 52 2818 Spectra obtained on 30 Jul 1995
95jul31.dat 52 2466 Spectra obtained on 31 Jul 1995
95jun09.dat 52 1410 Spectra obtained on 09 Jun 1995
95jun11.dat 52 705 Spectra obtained on 11 Jun 1995
95jun16.dat 52 351 Spectra obtained on 16 Jun 1995
95jun19.dat 52 702 Spectra obtained on 19 Jun 1995
95jun20.dat 52 2813 Spectra obtained on 20 Jun 1995
95may24.dat 52 2112 Spectra obtained on 24 May 1995
95may25.dat 52 2115 Spectra obtained on 25 May 1995
95nov03.dat 52 351 Spectra obtained on 03 Nov 1995
95nov06.dat 52 3525 Spectra obtained on 06 Nov 1995
95nov07.dat 52 3879 Spectra obtained on 07 Nov 1995
95nov09.dat 52 1761 Spectra obtained on 09 Nov 1995
95nov11.dat 52 1056 Spectra obtained on 11 Nov 1995
95nov12.dat 52 3879 Spectra obtained on 12 Nov 1995
95nov13.dat 52 4229 Spectra obtained on 13 Nov 1995
95nov14.dat 52 3525 Spectra obtained on 14 Nov 1995
95oct06.dat 52 3170 Spectra obtained on 06 Oct 1995
95oct08.dat 52 702 Spectra obtained on 08 Oct 1995
95oct10.dat 52 3525 Spectra obtained on 10 Oct 1995
95sep07.dat 52 2115 Spectra obtained on 07 Sep 1995
95sep08.dat 52 2819 Spectra obtained on 08 Sep 1995
95sep09.dat 52 2820 Spectra obtained on 09 Sep 1995
95sep10.dat 52 3171 Spectra obtained on 10 Sep 1995
95sep11.dat 52 1761 Spectra obtained on 11 Sep 1995
95sep13.dat 52 1410 Spectra obtained on 13 Sep 1995
96dec10.dat 52 2111 Spectra obtained on 10 Dec 1996
96dec11.dat 52 3522 Spectra obtained on 11 Dec 1996
96dec12.dat 52 351 Spectra obtained on 12 Dec 1996
96dec13.dat 52 3522 Spectra obtained on 13 Dec 1996
96dec15.dat 52 2820 Spectra obtained on 15 Dec 1996
96dec16.dat 52 3171 Spectra obtained on 16 Dec 1996
96dec18.dat 52 2106 Spectra obtained on 18 Dec 1996
96dec19.dat 52 1056 Spectra obtained on 19 Dec 1996
96dec21.dat 52 2112 Spectra obtained on 21 Dec 1996
96jan09.dat 52 351 Spectra obtained on 09 Jan 1996
96jul20.dat 52 1054 Spectra obtained on 20 Jul 1996
96jul22.dat 52 1761 Spectra obtained on 22 Jul 1996
96jul23.dat 52 1055 Spectra obtained on 23 Jul 1996
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Note on table2.dat: The centre of the circumstellar feature is taken at
the zero point of the velocity scale
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD HJD of mid observation
17- 20 F4.2 --- Depth ? Relative depth of absorption
25- 28 F4.2 --- e_Depth ? Formal uncertainty in relative depth (2)
32- 36 F5.1 km/s Vabs ? Velocity of absorption with respect to
central feature (1)
40- 43 F4.1 km/s e_Vabs ? Formal uncertainty in relative velocity (2)
47- 51 F5.1 km/s FWHM ? Full-Width at Half Maximum of absorption
55- 58 F4.1 km/s e_FWHM ? Formal uncertainty in FWHM (2)
61 A1 --- Line [hk] "h" if CaII H, "k" if CaII K
63 A1 --- SoB [sb] "s" if single feature, "b" if blended
65- 66 A2 --- Classif [g p ud] classification (3)
68 A1 --- CS_Affect [c] c: measures affected by central feature (4)
70- 71 A2 --- CR [cr ] cr: measures affected by a cosmic ray (4)
73 A1 --- By_eye [e] e: measures are by-eye estimates (4)
75- 88 A14 --- Comment Other comments
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Note (1): The zero point of the velocity scale is established only
approximately. See Section 2 of paper for discussion.
Note (2): Formal uncertainties are often felt to underestimate true
uncertainties. See Section 3 of paper for discussion.
Note (3): Quality classification of the measured CaII variable absorptions.
g: for single feature: an absorption that (possibly) no more than
slightly overlaps with another is well-fitted by a Gaussian
profile for .
for blended feature: an absorption that clearly overlaps with
one-or-more others is well-fitted by a Gaussian profile.
p: for single feature: an absorption that (possibly) no more than
slightly overlaps with another is a poorer fit to a Gaussian
profile, either because the spectrum is noisy or because the
profile is obviously non-Gaussian.
p: for blended feature: an absorption that clearly overlaps with
one-or-more others is a poorer fit to a Gaussian profile,
either because the spectrum is noisy or because the profile is
obviously non-Gaussian.
ud: `Uncertain Decomposition': the feature has been fitted by a single
Gaussian profile, but the signal-to-noise is insufficient to
determine whether multiple Gaussians would provide a better fit.
Note (4): c: The feature blends with the deep, narrow, stellar-velocity
circumstellar absorption, which has probably significantly
affected the Gaussian parameters of the fitted profile,
particularly if the division by the reference circumstellar
profile has been imperfect.
cr: The fit parameters are probably affected by imperfect filtering of
cosmic rays.
e: Fit parameters have been estimated by eye.
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Byte-by-byte Description of file: 9*.dat
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Bytes Format Units Label Explanations
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1- 11 A11 "YYYY-MM-DD" OBSDate UTC date of observation "year-mon-dy"
13- 20 A8 "h:m:s" OBStime UTC time of mid observation "hh:mm:ss"
22 A1 --- Line "H" if CaII H, "K" if CaII K
24- 29 F6.1 s Exposure Exposure duration
31- 33 F3.1 --- airmass Weighted airmass of observation
35- 41 F7.2 km/s HRV Approximate heliocentric radial velocity (1)
43- 52 F10.3 --- Flux Flux in arbitrary units (2)
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Note (1): The zero point of the velocity scale is established only
approximately. See Section 2 of paper for discussion.
Note (2): Examine the corresponding PostScript figure to ascertain
extent to which spectrum may be affected by cosmic ray strikes
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1 A1 --- Line "H" if CaII H, "K" if CaII K
3- 9 F7.2 km/s RV Approximate radial velocity with respect to
central absorption
11- 17 F7.3 --- Flux Flux in arbitrary units.
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Acknowledgments: William Tobin
(End) William Tobin [Astron., Univ. Canterbury, New Zealand] 05-Nov-1998