J/AJ/151/143 Silicon depletion in the interstellar medium (Haris+, 2016)
Silicon depletion in the interstellar medium.
Haris U., Parvathi V.S., Gudennavar S.B., Bubbly S.G., Murthy J.,
Sofia U.J.
<Astron. J., 151, 143-143 (2016)>
=2016AJ....151..143H 2016AJ....151..143H (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Interstellar medium ; Stars, nearby ; Spectral types ;
Stars, distances ; Extinction
Keywords: dust, extinction - ISM: abundances
Abstract:
We report interstellar silicon (Si) depletion and dust-phase column
densities of Si along 131 Galactic sight lines using archival
observations. The data were corrected for differences in the assumed
oscillator strength. This is a much larger sample than previous
studies but confirms the majority of results, which state that the
depletion of Si is correlated with the average density of hydrogen
along the line of sight (<n(H)>) as well as the fraction of hydrogen
in molecular form (f(H2)). We also find that the linear part of the
extinction curve is independent of Si depletion. Si depletion is
correlated with the bump strength (c3/RV) and the FUV curvature
(c4/RV) suggesting that silicon plays a significant role in both
the 2175Å bump and the FUV rise.
Description:
Gudennavar et al. (2012, J/ApJS/199/8) compiled absorption line data
for 3008 stars of which 131 sight lines included silicon column
densities that were taken over 30 years of observations (Table 1).
Most of the silicon lines (84) in our sample have come from
van Steenberg & Shull (1988ApJS...67..225V 1988ApJS...67..225V) who used archival
observations from the International Ultraviolet Explorer (IUE) to
derive column densities to a number of different species. Most of the
other observations (36) were made using the Goddard High Resolution
Spectrograph (Spitzer & Fitzpatrick 1995ApJ...445..196S 1995ApJ...445..196S; Savage & Sembach
1996ARA&A..34..279S 1996ARA&A..34..279S; Redfield & Linsky 2004ApJ...602..776R 2004ApJ...602..776R) or the
Space Telescope Imaging Spectrograph (Sonnentrucker et al.
2003ApJ...596..350S 2003ApJ...596..350S; Gnacinski & Krogulec 2006AcA....56..373G 2006AcA....56..373G;
Miller et al. 2007ApJ...659..441M 2007ApJ...659..441M) with higher resolution and better
signal-to-noise.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 98 131 Sight line Parameters and the revised column
densities of silicon
table3.dat 110 131 The column densities of hydrogen and calculated
parameters
table4.dat 59 42 *Extinction Parameters
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Note on table4.dat: Extinction parameters from Valencic et al.
(2004ApJ...616..912V 2004ApJ...616..912V).
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See also:
J/ApJS/94/127 : Distribution of H I in the ISM. I. (Fruscione+, 1994)
J/ApJS/163/282 : Molecular hydrogen column densities (Wakker+, 2006)
J/A+A/528/A92 : HERES VI. Galactic chemical evolution of Si and C
(Zhang+, 2011)
J/ApJS/199/8 : A compilation of interstellar column densities
(Gudennavar+, 2012)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Star Target star identifier
13- 18 F6.2 deg GLON [6.01/357.93] Galactic longitude (1)
20- 25 F6.2 deg GLAT [-62.73/65.32] Galactic latitude (1)
27- 47 A21 --- SpType MK spectral type (1)
49- 53 F5.3 kpc Dist [0.032/5] Distance (1)
55- 59 F5.3 mag E(B-V) [0/0.78]? The (B-V) color excess (1)
61- 65 F5.3 mag e_E(B-V) [0.01/0.08]? Uncertainty in E(B-V) (1)
67- 76 E10.4 cm-2 N(SII) ? Revised Si column density (2)
78- 87 E10.4 cm-2 E_N(SII) ? Upper uncertainty in N(SII) (2)
89- 98 E10.4 cm-2 e_N(SII) ? Lower uncertainty in N(SII) (2)
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Note (1): From Gudennavar et al. (2012, J/ApJS/199/8).
Note (2): Revised using latest oscillator strengths taken from NIST
(Kelleher & Podobedova 2008JPCRD..37.1285K 2008JPCRD..37.1285K).
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Star Target star identifier
13- 20 E8.2 cm-2 N(H) Hydrogen column density (1)
22- 29 E8.2 cm-2 E_N(H) ? Upper uncertainty in N(H) (1)
31- 38 E8.2 cm-2 e_N(H) ? Lower uncertainty in N(H) (1)
40- 48 E9.2 [-] logn(H) Logarithm of <n(H)> (2)
50- 58 E9.2 [-] logf(H2) ? Logarithm of f(H2) (3)
60- 68 E9.2 cm-2 NSiDust Column density of silicon in dust (4)
70- 77 E8.2 cm-2 E_NSiDust ? Upper uncertainty in NSiDust
79- 86 E8.2 cm-2 e_NSiDust ? Lower uncertainty
in NSiDust
88- 94 F7.4 --- D(Si) [-2.7515/0.5502] Silicon depletion (5)
96-103 F8.4 --- E_D(Si) ? Upper uncertainty in D(Si)
105-110 F6.4 --- e_D(Si) ? Lower uncertainty in D(Si)
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Note (1): From Gudennavar et al. (2012, J/ApJS/199/8).
Note (2): Where <n(H)≥N(H)/d, where d is the distance to the star.
Note (3): Where f(H2)=2N(H2)/[(N(HI)+2N(H2)].
Note (4): Which is calculated using the equation [N(Si)/N(H)]dust*N(H).
Note (5): Where D(Si)=-0.47 n(H).
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Star Target star identifier
11- 14 F4.2 --- 1/RV [0.17/0.5] Inverse of ratio of total to selective
extinction (1)
16- 19 F4.2 --- e_1/RV [0.01/0.16] Uncertainty in 1/RV
21- 24 F4.2 --- c1/RV [0.4/1.82] Parameter (c1/RV) for the intercept
of the non-linear FUV rise of the extinction
curve (2)
26- 29 F4.2 --- e_c1/RV [0.09/1.05] Uncertainty in c1/RV (2)
31- 34 F4.2 --- c2/RV [0/0.45] Parameter (c2/RV) for the slope of
the non-linear FUV rise of the extinction curve
(2)
36- 39 F4.2 --- e_c2/RV [0/0.15] Uncertainty in c2/RV (2)
41- 44 F4.2 --- c3/RV [0.23/1.87] Parameter (c3/RV) for the 2175Å
bump strength of the non-linear FUV rise of
the extinction curve (2)
46- 49 F4.2 --- e_c3/RV [0.04/0.41] Uncertainty in c3/RV (2)
51- 54 F4.2 --- c4/RV [0.01/0.39] Parameter (c4/RV) for the strength
of the non-linear FUV rise of the extinction
curve (2)
56- 59 F4.2 --- e_c4/RV [0.01/0.1] Uncertainty in c4/RV (2)
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Note (1): Where RV=AV/E(B-V).
Note (2): Parameter from Fitzpatrick & Massa (1988ApJ...328..734F 1988ApJ...328..734F).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 29-Mar-2018