Towards an understanding of the Of?p star HD 191612: Optical spectroscopy

Ian D. Howarth; Nolan R. Walborn; Danny J. Lennon; Joachim Puls; Yaël Nazé; K. Annuk; I. Antokhin; D. Bohlender; H. Bond; J. F. Donati; L. Georgiev; D. Gies; D. Harmer; A. Herrero; I. Kolka; D. McDavid; T. Morel; I. Negueruela; G. Rauw; P. Reig

doi:10.1111/j.1365-2966.2007.12178.x

Towards an understanding of the Of?p star HD 191612: Optical spectroscopy

Ian D. Howarth, Nolan R. Walborn, Danny J. Lennon, Joachim Puls, Yaël Nazé, K. Annuk, I. Antokhin, D. Bohlender, H. Bond, J. F. Donati, L. Georgiev, D. Gies, D. Harmer, A. Herrero, I. Kolka, D. McDavid, T. Morel, I. Negueruela, G. Rauw, P. Reig

Astronomy & Astrophysics

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Abstract

We present extensive optical spectroscopy of the early-type magnetic star HD 191612 (O6.5f?pe-O8fp). The Balmer and He i lines show strongly variable emission which is highly reproducible on a well-determined 538-d period. He ii absorptions and metal lines (including many selective emission lines but excluding He ii λ4686 Å emission) are essentially constant in line strength, but are variable in velocity, establishing a double-lined binary orbit with P_orb = 1542 d, e = 0.45. We conduct a model-atmosphere analysis of the spectrum, and find that the system is consistent with a ∼O8 giant with a ∼B1 main-sequence secondary. Since the periodic 538-d changes are unrelated to orbital motion, rotational modulation of a magnetically constrained plasma is strongly favoured as the most likely underlying 'clock'. An upper limit on the equatorial rotation is consistent with this hypothesis, but is too weak to provide a strong constraint.

Original language	English (US)
Pages (from-to)	433-446
Number of pages	14
Journal	Monthly Notices of the Royal Astronomical Society
Volume	381
Issue number	2
DOIs	https://doi.org/10.1111/j.1365-2966.2007.12178.x
State	Published - Oct 2007

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

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10.1111/j.1365-2966.2007.12178.x

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Howarth, I. D., Walborn, N. R., Lennon, D. J., Puls, J., Nazé, Y., Annuk, K., Antokhin, I., Bohlender, D., Bond, H., Donati, J. F., Georgiev, L., Gies, D., Harmer, D., Herrero, A., Kolka, I., McDavid, D., Morel, T., Negueruela, I., Rauw, G., & Reig, P. (2007). Towards an understanding of the Of?p star HD 191612: Optical spectroscopy. Monthly Notices of the Royal Astronomical Society, 381(2), 433-446. https://doi.org/10.1111/j.1365-2966.2007.12178.x

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title = "Towards an understanding of the Of?p star HD 191612: Optical spectroscopy",

abstract = "We present extensive optical spectroscopy of the early-type magnetic star HD 191612 (O6.5f?pe-O8fp). The Balmer and He i lines show strongly variable emission which is highly reproducible on a well-determined 538-d period. He ii absorptions and metal lines (including many selective emission lines but excluding He ii λ4686 {\AA} emission) are essentially constant in line strength, but are variable in velocity, establishing a double-lined binary orbit with Porb = 1542 d, e = 0.45. We conduct a model-atmosphere analysis of the spectrum, and find that the system is consistent with a ∼O8 giant with a ∼B1 main-sequence secondary. Since the periodic 538-d changes are unrelated to orbital motion, rotational modulation of a magnetically constrained plasma is strongly favoured as the most likely underlying 'clock'. An upper limit on the equatorial rotation is consistent with this hypothesis, but is too weak to provide a strong constraint.",

author = "Howarth, {Ian D.} and Walborn, {Nolan R.} and Lennon, {Danny J.} and Joachim Puls and Ya{\"e}l Naz{\'e} and K. Annuk and I. Antokhin and D. Bohlender and H. Bond and Donati, {J. F.} and L. Georgiev and D. Gies and D. Harmer and A. Herrero and I. Kolka and D. McDavid and T. Morel and I. Negueruela and G. Rauw and P. Reig",

year = "2007",

month = oct,

doi = "10.1111/j.1365-2966.2007.12178.x",

language = "English (US)",

volume = "381",

pages = "433--446",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

publisher = "Oxford University Press",

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Howarth, ID, Walborn, NR, Lennon, DJ, Puls, J, Nazé, Y, Annuk, K, Antokhin, I, Bohlender, D, Bond, H, Donati, JF, Georgiev, L, Gies, D, Harmer, D, Herrero, A, Kolka, I, McDavid, D, Morel, T, Negueruela, I, Rauw, G & Reig, P 2007, 'Towards an understanding of the Of?p star HD 191612: Optical spectroscopy', Monthly Notices of the Royal Astronomical Society, vol. 381, no. 2, pp. 433-446. https://doi.org/10.1111/j.1365-2966.2007.12178.x

TY - JOUR

T1 - Towards an understanding of the Of?p star HD 191612

T2 - Optical spectroscopy

AU - Howarth, Ian D.

AU - Walborn, Nolan R.

AU - Lennon, Danny J.

AU - Puls, Joachim

AU - Nazé, Yaël

AU - Annuk, K.

AU - Antokhin, I.

AU - Bohlender, D.

AU - Bond, H.

AU - Donati, J. F.

AU - Georgiev, L.

AU - Gies, D.

AU - Harmer, D.

AU - Herrero, A.

AU - Kolka, I.

AU - McDavid, D.

AU - Morel, T.

AU - Negueruela, I.

AU - Rauw, G.

AU - Reig, P.

PY - 2007/10

Y1 - 2007/10

N2 - We present extensive optical spectroscopy of the early-type magnetic star HD 191612 (O6.5f?pe-O8fp). The Balmer and He i lines show strongly variable emission which is highly reproducible on a well-determined 538-d period. He ii absorptions and metal lines (including many selective emission lines but excluding He ii λ4686 Å emission) are essentially constant in line strength, but are variable in velocity, establishing a double-lined binary orbit with Porb = 1542 d, e = 0.45. We conduct a model-atmosphere analysis of the spectrum, and find that the system is consistent with a ∼O8 giant with a ∼B1 main-sequence secondary. Since the periodic 538-d changes are unrelated to orbital motion, rotational modulation of a magnetically constrained plasma is strongly favoured as the most likely underlying 'clock'. An upper limit on the equatorial rotation is consistent with this hypothesis, but is too weak to provide a strong constraint.

AB - We present extensive optical spectroscopy of the early-type magnetic star HD 191612 (O6.5f?pe-O8fp). The Balmer and He i lines show strongly variable emission which is highly reproducible on a well-determined 538-d period. He ii absorptions and metal lines (including many selective emission lines but excluding He ii λ4686 Å emission) are essentially constant in line strength, but are variable in velocity, establishing a double-lined binary orbit with Porb = 1542 d, e = 0.45. We conduct a model-atmosphere analysis of the spectrum, and find that the system is consistent with a ∼O8 giant with a ∼B1 main-sequence secondary. Since the periodic 538-d changes are unrelated to orbital motion, rotational modulation of a magnetically constrained plasma is strongly favoured as the most likely underlying 'clock'. An upper limit on the equatorial rotation is consistent with this hypothesis, but is too weak to provide a strong constraint.

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DO - 10.1111/j.1365-2966.2007.12178.x

M3 - Article

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VL - 381

SP - 433

EP - 446

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 2

ER -

Towards an understanding of the Of?p star HD 191612: Optical spectroscopy

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