Dynamical, Spatial and Chemical Properties of h Carinae’s Heavy Metal (i.e., Sr) Filaments:

Dynamical, Spatial and Chemical Propertiesof Carinae’s Heavy Metal (i.e., Sr) Filaments:

First VLT/UVES Results

B. N. Dorland (Physics Dept., University of Maryland & Astrometry Dept., U.S. Naval Observatory, Wash. DC)D. G. Currie (Physics Dept., University of Maryland & European Southern Observatory, Garching bei Muenchen, Germany)

A. Kaufer (European Southern Observatory, Santiago, Chile)

Line Identification

UVES Observations and Data Reduction

• Very Large Telescope (VLT) / Ultraviolet and Visible Echelle Spectrograph (UVES) observations of Carinae were made in December 1999 and January 2000.

• Dec. 1999 observations were aligned along the Homunculus axis of symmetry (AOS), PA = 45 deg.

• Jan. 2000 observations were aligned perpendicular to the AOS, PA = 135 deg. Slits were positioned every ~1 arcsec NW of central star, from 0 through 4.

• Dichroic #1 mode was employed. Spectral coverage:– 3100 – 3866 angstroms (“blue arm”)– 4791 – 6798 angstroms (“red arm”)

• Spatial coverage:– 10 arcsec (blue)– 12 arcsec (red)

• Spectral resolution:– / blue), 100 000 (red)

• Resultant data has:– Spatial scale = 0.182 arcsec (blue) and 0.246

arcsec (red) per pixel– Spectral scale = 0.02 angstroms per pixel

Figure 1. UVES Long Slit Observations

• The Carinae observations represent the first use of UVES with extended objects. Calibration and initial reduction was performed at the ESO Vitacura facility using the ESO-MIDAS data reduction system using modified versions of the UVES and FEROS contexts.

• Analysis pre-analysis reduction included:– High-frequency noise reduction using a 3x3 pixel median filter.– Low-frequency signal reduction using 100 km/sec median filter subtraction.

Methodology:• Two of Zethson lines correlated with two high S/N lines in 2000 UVES data in Slit 1 (see Table I and Fig. 2).

• In slit 2, lines are both blue shifted by 30 km/sec.

• In slit 2, line strength drops by ~50%.• Line identification template thus consisted of looking for lines of similar width and reduced amplitude, offset by -30 km/sec between slit 1 and slit 2.

• In 1999, Zethson, Johansson, Davidson et al. reported HST/HRS detection of very slow (|VDoppler|<100 km/sec) gas in the equatorial zone of the Homunculus.

• In 2001, Zethson, Gull, Hartmann et al. reported HST/STIS results identifying a Strontium “patch” in the equatorial zone. The characteristics of the patch were:

– Strong source of [Sr II] emission– Velocity system line peak velocities: VDoppler = -

100 +/-15 km/sec.– Narrow Lines: FWHM ~ 50 km/sec– Centered at ~ 1.55” NW of central star

position, approximately along the Homunculus axis of symmetry.

The Heavy Metal (i.e., Sr) Filaments:Introduction

• By using VDoppler as a discriminant, Zethson et al. identified a multitude of other forbidden lines as being part of the Sr patch velocity system. These include:

– [Ti II], [Mn II], [Fe I], [Fe II], [Co II], [Ni II]• Hartmann, Zethson, Johansson, et al., (2001) published a new set of line identifications for the Sr patch (“filament”) that included:

– Sc I & II, Ti I & II, V I & II, Fe I and Ni II• Zethson et al. originally proposed Sr overabundance as the cause of strong [Sr II] emissions.

• Bautista, Gull, Ishibashi et al. later proposed (2001) a mechanism involving continuum flourescence and high electron density that does not require Sr overabundance.

Zethson et al.

(vacuum) Angstroms

UVES line centroid (air) Angstroms

Zero Velocity w.l. (air)

Angstroms

Doppler Velocity km/sec

[Sr II] 6738.04 6736.65 6738.44 -76.87

[Fe I] 6760.35 6758.89 6760.619 -79.61

Table 1. Paradigm line characteristics for 2000 UVES data, slit 1.

Results:• 49 “probable” line associations (and IDs) with the Heavy Metal velocity system (see Table II). These include:

– Seven forbidden Fe I, one forbidden Sr II and one forbidden Ti II

– 16 permitted Fe I– Six permitted Sc II– 13 permitted Ti II– Five permitted V II

• For slit 1, we get: – <VDoppler> = -76.06 +/- 3.09 km/sec– <FWHM> = 16.09 +/- 4.33 km/sec

• The extremely tight velocity agreement between lines allows us to have high confidence in the line identifications.

• We cannot confirm the identification in Zethson et al. (2001) of either [Mn II] or [Co II]. Only some of the spectrally accessible lines are present in the UVES data. Of these, none of the lines appear to be in the Heavy Metal velocity system.

ABSTRACT We report on the first VLT/UVES observations of the Heavy Metal (i.e., Sr) Filaments near the star Carinae. Previous observations had detected a feature dubbed the “Strontium Patch”; in these observations, we resolve the “Patch” into two distinct filaments and five constituent clumps in velocity space. We find that the brighter filament is linear in velocity space (i.e., it obeys a “Hubble-law” like velocity-distance relation), while the second, dimmer filament is curved in velocity space, indicating possible deceleration of the filamentary material. We confirm and extend previous observations of 40 permitted lines of Fe I, Sc II, Ti II, V II and nine forbidden lines of [Fe I], [Ti II], and [Sr II]. We determine the spatial extent of the features and find that the filaments from 0 arcsec to 4 arcsec NW of the central star, vary in width from 1 to 1.5 arcsec, and are aligned along the Homunculus axis of symmetry +/- 0.2 arcsec. We find that the linear filament is anchored by a feature that coincides in both position and velocity with Weigelt blobs C and D, and conclude that the linear filament material was most likely ejected from a source related to the Weigelt blobs. Given this assumption, we calculate an inclination angle of 73 +/- 8 deg for the principal (linear) filament with respect to the Homunculus axis of symmetry, or somewhat above the equaotorial plane.

[Sr I

I]67

38.4

4

[Fe

I]67

60.6

19

[Ti I

I]67

25.8

7

[Fe

I]67

47.1

7

[S II

]67

16.4

2

[S II

]67

30.7

4

[Sr I

I]67

38.4

4

[Fe

I]67

60.6

19

[Ti I

I]67

25.8

7

[Fe

I]67

47.1

7

[S II

]67

16.4

2

[S II

]67

30.7

4

Figure 2. UVES data, slits 1 (upper panel) and 2 (lower panel) for 6700-6780 Angstroms. Data are integrated over spatial rows. Identifications are marked over prominent lines. GREEN designates “template lines” used to identify other lines in the Heavy Metal velocity system. YELLOW indicates lines that are probably not in HM system or are otherwise problematic.

AD

Us

AD

Us

Table 2. Probable Heavy Metal Lines associated with Sr Velocity System

Notes:1- IDs are from Gull (2002)2- IDs are from Zethson et al (2001)

Spatial Properties

3-D Orientation of the Linear Filament

Loose Ends

References• Currie, D., Dowling, D., Shaya, E., et al., 1996, AJ, 112, 115• Cox, P., et al., 1995, ASP Conf. Series, 120, 277 • Davidson, K. Ebberts, D., Johansson, S., et al., 1997, AJ, 113, 335• Daminelli, A., Stahl, O., Kaufer, A., et al., 1998, A&A Supl. Series, 133, 299• Gull, T., 2002, Private Communication• Hartmann, H., Zethson, T., Johansson, S., et al., 2001, PASP, 242, 107• Weigelt, G., Albrecht, R., Barbieri, C., et al., 1995, RMxAC, 2, 11• Zethson, T., Johanson, S., Davidson, K., et al., 1999, A&A, 344, 211• Zethson, T., Gull, T., Hartmann, H., et al., 2001, AJ,122, 322

Dynamical Properties

[Fe I](7 lines)

Ti II(13 lines)

Fe I(16 lines)

V II(5 lines)

Sc II(6 lines)

0”

1”

2”

3”

4”

0”

1”

2”

3”

4”

0”

1”

2”

3”

4”

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1”

2”

3”

4”

0”

1”

2”

3”

4”

-100 0-50-150-100 0-50-150

-100 0-50-150

LinearFilament

CurvedFilament

CF1

CF2

LF2

(spuriousfeature)

LF3

LF2LF1

CF2 CF1

CF1LF3

LF2

LF1

CF1

LF2

LF1

LF2

LF1

Figure 3. Axis of symmetry data, coadded over indicated number of lines. From 1999 UVES data. Velocity scale is in km/sec, spatial scale in arc seconds.

UVES observations (Fig. 3) reveal the “Patch” actually consists of two distinct filaments:

• “Linear Filament” (LF)– Brighter filament– Corresponds to Zethson patch– Straight-line in velocity space, thus it obeys a

“Hubble-law” like distance-velocity relation.– Extends from ~0 to ~2 arcsec NW from the central

star.• “Curved Filament” (CF)

– Fainter filament– Connects to Linear Filament; connection most

prominent in [Fe I] images.– Curved in velocity space, we infer that filamentary

material is decelerating– Extends from ~2 to ~4 arcsec NW from the central

star. Table 3. Velocity and spatial properties of clumps from Fig. 3.(Fe I lines used for calculations)

UVES data also reveal that the filaments are “clumpy”.

• The Linear Filament consists of clumps LF1, LF2, and LF3; the Curved Filament consists of CF1 and CF2. Velocity and spatial offsets and widths are given in Table 3.

• CF1 appears to mark the end of the Curved Filament. It is faint; it appears in all images except Sc II.

• CF2 is most prominent in the Fe I image; also seems to be present in [Fe I] and possibly Ti II and V II.

• LF2 is present in all images; it seems to correspond to the Zethson patch.

• LF3 appears to mark the end of the linear filament; it is prominent in Fe I and Ti II images.

• LF1 marks the base of the linear filament. Its position and velocity are consistent with Weigelt blobs C and D (Weigelt et al., 1995; Davidson et al., 1997).

Dynamical Analysis Conclusions:1. Linear filament suggests that all Heavy Metal

material was ejected during a single event.2. Correlation of base of the Linear Filament with

Weigelt blobs suggest that the source of the filaments is related to the source of the Weigelt blobs.

3. Curved Filament material has most likely undergone deceleration; material was originally associated with the Linear Filament.

Plane of sky motion~300 km/sec

Doppler velocity~ -110 km/sec

Resultant angle:~ 20 deg w/r/t the plane of the sky

Figure 5. LF3 kinematics analysis. We assume systemic velocity ~ -10 km/sec and Weigelt ejection date ~ 1920 C.E..

Plane of the sky

Line of sighti = 40 deg

Homunculusaxis of symmetry

Equatorial plane

= 73 +/-8 deg

Linear Filament

Figure 6. Resultant Linear Filament orientation. Range in angles is due to uncertainty in origination dates for Weigelt blobs. Dates considered are from 1842 to 1935.

Velocities are in central star reference frame

If we assume the Linear Filament is anchored by LF1, and that LF1 is correlated to Weigelt blobs C and D, we can calculate the 3D orientation of the filament.

• Using the velocity and offset values from Table 3 for LF1 and LF3 (the beginning and end points for the Linear Filament), and assuming a systemic VDoppler= -10 km/sec, we obtain a VDoppler ~ 110 km/sec for LF3 in the central star reference frame.

• Assuming LF1<->Weigelt CD (unresolved), we can use Weigelt et al.’s (1995) result for plane of sky motion (~ 4 mas/year), and assuming a distance of 2.2 Kpc, we calculate a plane of sky motion for LF3 ~ 300 km/sec in the central star reference frame. See Fig. 5.

o

3-D Orientation Analysis Conclusions:1. Combining these results, we get an orientation angle of ~20 deg

w/r/t the plane of the sky. 2. Assuming an inclination angle of ~40 deg (Currie 1996), we

obtain an inclination angle of 70 degrees for the Linear Filament w/r/t the Homunculus axis of symmetry (see Fig. 6).

3. If we consider a range of possible ejection dates for Weigelt C and D from 1842 to 1935, we get a range of possible orientation angles for the Linear Filament of 65-81 deg, all of which are above the equatorial plane.

-100 -50 0-150

-100 -50 0-150

-1”

+1”

0”

-1”

+1”

0”

-1”

+1”

0”

-1”

+1”

0”

[Fe I] Lines-100 -50 0-150

Fe I Lines

-100 -50 0-150

-1”

+1”

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-1”

+1”

0”

-1”

+1”

0”

-1”

+1”

0”

Slit 1Slit 2

Slit 3Slit 4

LF2

LF2 CF

CF1CF2?

CF1

LF2

LF2

CF1CF2

CF1

Using the UVES 2000 [Fe I] and Fe I observations, we have measured the spatial widths of the features identified above. Data are shown in Fig. 4; results are given in Table 4.

• Linear Filament features expand gradually between slits 1 and 4.• Slit 2, [Fe I] image shows what appears to be the Curved Filament “pulling away” (i.e., decelerating with respect to) the Linear filament.

• In general, the features are centered along the Homunculus axis of symmetry, and are of widths 1-1.5 arcseconds. Figure 4. 2000 “grid” data for [Fe I] and

Fe I lines used to measure spatial properties of various features.

Table 4. Spatial Properties of clumps from 2000 slit data for [Fe I] and Fe I lines.

Various questions and issues have arisen as a result of this analysis. These include:• ~ 50 other candidate lines have been identified as possible HMF lines. They include Y II. Which of these lines are actually part of the HMF system?

• Is the HMF related to the “paddle”? • Is the HMF related to Morse’s region of “Blue Glow”? (Morse 1998)• Is LF1 <-> Weigelt C+D?• What is (are) the correct ejection date(s) for Weigelt C and D?• What is the systemic velocity of Carinae?

– LF1 has a VDoppler~ -50 km/sec.– Both Cox (1995) and Daminelli (1998) have found possible systemic VDoppler of -40 - -50 km/sec.– Is it mere coincidence that LF1 and CF1 have nearly the same VDoppler? Has CF1 material decelerated to the

velocity of the ambient medium? If so, that would suggest a systemic VDoppler = -50 km/sec rather than the canonical -10 km/sec.