Raman-scattered He II λ6545 line in the symbiotic star V1016 Cygni

Hee Won Lee, Young Jong Sohn, Young Woon Kang, Ho Il Kim

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

We present a spectrum of the symbiotic star V1016 Cyg observed with the 3. 6 m Canada-France-Hawaii Telescope, in order to illustrate a method to measure the covering factor of the neutral scattering region around the giant component with respect to the hot emission region around the white dwarf component. In the spectrum, we find broad wings around Hα and a broad emission feature around 6545 Å that is blended with the [N II] λ6548 line. These two features are proposed to be formed by Raman scattering by atomic hydrogen, where the incident radiation is proposed to be UV continuum radiation around Lyβ in the former case and the He II λ1025 emission line arising from n = 6 → n = 2 transitions for the latter feature. We remove the Hα wings by a template Raman scattering wing profile and subtract the [N II] λ6548 line using the 3 times stronger [N II] λ6583 feature in order to isolate the He II Raman-scattered. 6545 Å line. We obtain the flux ratio F6545/F6560 = 0.24 of the He II λ6560 emission line and the 6545 Å feature for V1016 Cyg. Under the assumption that the He II emission from this object is isotropic, this ratio is converted to the ratio Φ65451025 = 0.17 of the number of the incident photons and that of the scattered photons. This implies that the scattering region with H I column density NH I ≥ 1020 cm-2 covers 17% of the emission region. By combining the presumed binary period of ∼100 yr for this system we infer that a significant fraction of the slow stellar wind from the Mira component is ionized and that the scattering region around the Mira extends a few tens of AU, which is closely associated with the mass loss process of the Mira component. It is argued that the Raman-scattered He II λ6545 line is an important and useful tool to investigate the mass-loss process occurring in the late stage of stellar evolution.

Original languageEnglish
Pages (from-to)553-559
Number of pages7
JournalAstrophysical Journal
Volume598
Issue number1 I
DOIs
Publication statusPublished - 2003 Nov 20

Fingerprint

symbiotic stars
scattering
wings
wing profiles
Raman spectra
incident radiation
stellar evolution
stellar winds
photons
France
Canada
coverings
templates
telescopes
hydrogen
continuums
radiation

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Lee, Hee Won ; Sohn, Young Jong ; Kang, Young Woon ; Kim, Ho Il. / Raman-scattered He II λ6545 line in the symbiotic star V1016 Cygni. In: Astrophysical Journal. 2003 ; Vol. 598, No. 1 I. pp. 553-559.
@article{e4266fdf0bfb4443af7f776db201ae36,
title = "Raman-scattered He II λ6545 line in the symbiotic star V1016 Cygni",
abstract = "We present a spectrum of the symbiotic star V1016 Cyg observed with the 3. 6 m Canada-France-Hawaii Telescope, in order to illustrate a method to measure the covering factor of the neutral scattering region around the giant component with respect to the hot emission region around the white dwarf component. In the spectrum, we find broad wings around Hα and a broad emission feature around 6545 {\AA} that is blended with the [N II] λ6548 line. These two features are proposed to be formed by Raman scattering by atomic hydrogen, where the incident radiation is proposed to be UV continuum radiation around Lyβ in the former case and the He II λ1025 emission line arising from n = 6 → n = 2 transitions for the latter feature. We remove the Hα wings by a template Raman scattering wing profile and subtract the [N II] λ6548 line using the 3 times stronger [N II] λ6583 feature in order to isolate the He II Raman-scattered. 6545 {\AA} line. We obtain the flux ratio F6545/F6560 = 0.24 of the He II λ6560 emission line and the 6545 {\AA} feature for V1016 Cyg. Under the assumption that the He II emission from this object is isotropic, this ratio is converted to the ratio Φ6545/Φ1025 = 0.17 of the number of the incident photons and that of the scattered photons. This implies that the scattering region with H I column density NH I ≥ 1020 cm-2 covers 17{\%} of the emission region. By combining the presumed binary period of ∼100 yr for this system we infer that a significant fraction of the slow stellar wind from the Mira component is ionized and that the scattering region around the Mira extends a few tens of AU, which is closely associated with the mass loss process of the Mira component. It is argued that the Raman-scattered He II λ6545 line is an important and useful tool to investigate the mass-loss process occurring in the late stage of stellar evolution.",
author = "Lee, {Hee Won} and Sohn, {Young Jong} and Kang, {Young Woon} and Kim, {Ho Il}",
year = "2003",
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Raman-scattered He II λ6545 line in the symbiotic star V1016 Cygni. / Lee, Hee Won; Sohn, Young Jong; Kang, Young Woon; Kim, Ho Il.

In: Astrophysical Journal, Vol. 598, No. 1 I, 20.11.2003, p. 553-559.

Research output: Contribution to journalArticle

TY - JOUR

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N2 - We present a spectrum of the symbiotic star V1016 Cyg observed with the 3. 6 m Canada-France-Hawaii Telescope, in order to illustrate a method to measure the covering factor of the neutral scattering region around the giant component with respect to the hot emission region around the white dwarf component. In the spectrum, we find broad wings around Hα and a broad emission feature around 6545 Å that is blended with the [N II] λ6548 line. These two features are proposed to be formed by Raman scattering by atomic hydrogen, where the incident radiation is proposed to be UV continuum radiation around Lyβ in the former case and the He II λ1025 emission line arising from n = 6 → n = 2 transitions for the latter feature. We remove the Hα wings by a template Raman scattering wing profile and subtract the [N II] λ6548 line using the 3 times stronger [N II] λ6583 feature in order to isolate the He II Raman-scattered. 6545 Å line. We obtain the flux ratio F6545/F6560 = 0.24 of the He II λ6560 emission line and the 6545 Å feature for V1016 Cyg. Under the assumption that the He II emission from this object is isotropic, this ratio is converted to the ratio Φ6545/Φ1025 = 0.17 of the number of the incident photons and that of the scattered photons. This implies that the scattering region with H I column density NH I ≥ 1020 cm-2 covers 17% of the emission region. By combining the presumed binary period of ∼100 yr for this system we infer that a significant fraction of the slow stellar wind from the Mira component is ionized and that the scattering region around the Mira extends a few tens of AU, which is closely associated with the mass loss process of the Mira component. It is argued that the Raman-scattered He II λ6545 line is an important and useful tool to investigate the mass-loss process occurring in the late stage of stellar evolution.

AB - We present a spectrum of the symbiotic star V1016 Cyg observed with the 3. 6 m Canada-France-Hawaii Telescope, in order to illustrate a method to measure the covering factor of the neutral scattering region around the giant component with respect to the hot emission region around the white dwarf component. In the spectrum, we find broad wings around Hα and a broad emission feature around 6545 Å that is blended with the [N II] λ6548 line. These two features are proposed to be formed by Raman scattering by atomic hydrogen, where the incident radiation is proposed to be UV continuum radiation around Lyβ in the former case and the He II λ1025 emission line arising from n = 6 → n = 2 transitions for the latter feature. We remove the Hα wings by a template Raman scattering wing profile and subtract the [N II] λ6548 line using the 3 times stronger [N II] λ6583 feature in order to isolate the He II Raman-scattered. 6545 Å line. We obtain the flux ratio F6545/F6560 = 0.24 of the He II λ6560 emission line and the 6545 Å feature for V1016 Cyg. Under the assumption that the He II emission from this object is isotropic, this ratio is converted to the ratio Φ6545/Φ1025 = 0.17 of the number of the incident photons and that of the scattered photons. This implies that the scattering region with H I column density NH I ≥ 1020 cm-2 covers 17% of the emission region. By combining the presumed binary period of ∼100 yr for this system we infer that a significant fraction of the slow stellar wind from the Mira component is ionized and that the scattering region around the Mira extends a few tens of AU, which is closely associated with the mass loss process of the Mira component. It is argued that the Raman-scattered He II λ6545 line is an important and useful tool to investigate the mass-loss process occurring in the late stage of stellar evolution.

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