On the Nature of X Persei: Evidence from the 1957 Outburst

Wackerling, Lloyd R.

doi:10.1086/129388

Cited by 5 publications

(3 citation statements)

References 21 publications

(39 reference statements)

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“…Significant variations in the Violet (V ) and Red (R) peak ratios of the Balmer and Fe ii emission lines were noted by Mc Laughlin in 1929, 1934and 1936(1937Cowley et al 1972), a pattern which continued between November 1957-January 1961, when Wackerling (1972) describes abrupt changes in the V/R ratio of the Balmer and metallic emission lines -the ratio changing from ∼1.5 in Feb. 1957 to ∼0.6 by the autumn of that year. Systematic, cyclic variability was again observed in late 1959-early 1960 with the V/R ratio plot of Hβ shown in Cowley et al (1972) clearly showing the onset of cyclic V/R variability around 1960, with a possible period of around 10 years.…”

Section: Previous Photometric and Spectroscopic Behaviour: 1913-1982mentioning

confidence: 94%

Phase changes of the Be/X-ray binary X Persei

Clark

Tarasov

Okazaki

et al. 2001

A&A

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Abstract. We present high resolution optical spectroscopy and V band photometry obtained during the period 1987-2001 for the Be star X Persei/HD 24534, the counterpart to the X-ray pulsar 4U 0352+30. We find that throughout this interval X Per is highly active, with significant photometric and spectroscopic variability. We identify one episode of complete disc loss during this period (1988 May-1989, characterised by significant ∆V = 0.6 mag optical fading and the presence of purely photospheric Hα and He i 6678Å lines. Two further episodes of pronounced optical fading which did not result in the complete dispersal of the circumstellar disc were also identified October-1995 October and 1999. The emission line profiles of both Hα and He i 6678Å also show significant variability. Cyclic changes in the strength of the peaks in both emission lines are observed, with periods ranging from 0.6-2 yrs -we attribute these to the presence of a one armed density wave in the inner circumstellar disc. Additional structure at large projected velocities is also present in the He i line -suggesting the presence of a significant density enhancement in the disc near the stellar surface (the "double disc" of Tarasov & Roche). The evolution of the outer edge of the Hα emitting region of the circumstellar disc is followed during disc formation, and is found to increase rather slowly. This observation, combined with the presence of the one armed density wave and the rate of disc formation and loss all provide strong evidence for the hypothesis that the circumstellar disc of X Per is a viscous decretion disc, with angular momentum being supplied by an as yet unknown physical mechanism near the stellar surface.

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Section: Previous Photometric and Spectroscopic Behaviour: 1913-1982mentioning

confidence: 94%

Phase changes of the Be/X-ray binary X Persei

Clark

Tarasov

Okazaki

et al. 2001

A&A

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“…We confirm only 8 of them, among which ζ Per (HIP18246, B1Ib), 40 Per (HIP17313, B0.5V), and AG Per (HIP19201, B5V:p; but see Giménez & Clausen 1994). Three of the 9 rejected classical proper motion members have unreliable or insignificant astrometric parameters: HIP17631 (B3IV...), X Per (HIP18350, O9.5pe; also known as 'non-conventional member' [e.g., Borgman & Blaauw 1964;Wackerling 1972;Sargent 1979]), and BD+31 643 7 (HIP17465, B5V; brightest member of IC348, of which Gingrich 12 [HIP17468, A2] is another member). Another three were already suspected to be peculiar or even non members: o Per (HIP17448, B1III; see e.g., Delhaye & Blaauw 1953;Fredrick 1954Fredrick , 1956Sargent 1979;Snow et al 1994), HD21483 (HIP16203, B3III; cf.…”

Section: Perseus Ob2mentioning

confidence: 99%

A [ITAL]Hipparcos[/ITAL] Census of the Nearby OB Associations

Zeeuw¹,

Hoogerwerf²,

Bruijne³

et al. 1999

The Astronomical Journal

1,205

118

1,616

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A comprehensive census of the stellar content of the OB associations within 1 kpc from the Sun is presented, based on Hipparcos positions, proper motions, and parallaxes. It is a key part of a long-term project to study the formation, structure, and evolution of nearby young stellar groups and related star-forming regions.OB associations are unbound 'moving groups', which can be detected kinematically because of their small internal velocity dispersion. The nearby associations have a large extent on the sky, which traditionally has limited astrometric membership determination to bright stars (V ∼ < 6 m ), with spectral types earlier than ∼B5. The Hipparcos measurements allow a major improvement in this situation. Moving groups are identified in the Hipparcos Catalogue by combining de Bruijne's refurbished convergent point method with the 'Spaghetti method' of Hoogerwerf & Aguilar. Astrometric members are listed for 12 young stellar groups, out to a distance of ∼650 pc. These are the 3 subgroups Upper Scorpius, Upper Centaurus Lupus and Lower Centaurus Crux of Sco OB2, as well as Vel OB2, Tr 10, Col 121, Per OB2, α Persei (Per OB3), Cas-Tau, Lac OB1, Cep OB2, and a new group in Cepheus, designated as Cep OB6. The selection procedure corrects the list of previously known astrometric and photometric B-and A-type members in these groups, and identifies many new members, including a significant number of F stars, as well as evolved stars, e.g., the Wolf-Rayet stars γ 2 Vel (WR11) in Vel OB2 and EZ CMa (WR6) in Col 121, and the classical Cepheid δ Cep in Cep OB6. Membership probabilities are given for all selected stars. Monte Carlo simulations are used to estimate the expected number of interloper field stars. In the nearest associations, notably in Sco OB2, the later-type members include T Tauri objects and other stars in the final pre-main sequence phase. This provides a firm link between the classical high-mass stellar content and ongoing low-mass star formation. Detailed studies of these 12 groups, and their relation to the surrounding interstellar medium, will be presented elsewhere.Astrometric evidence for moving groups in the fields of R CrA, CMa OB1, Mon OB1, Ori OB1, Cam OB1, Cep OB3, Cep OB4, Cyg OB4, Cyg OB7, and Sct OB2, is inconclusive. OB associations do exist in many of these regions, but they are either at distances beyond ∼500 pc where the Hipparcos parallaxes are of limited use, or they have unfavorable kinematics, so that the group proper motion does not distinguish it from the field stars in the Galactic disk.The mean distances of the well-established groups are systematically smaller than the pre-Hipparcos photometric estimates. While part of this may be caused by the improved membership lists, a recalibration of the upper main sequence in the Hertzsprung-Russell diagram may be called for. The mean motions display a systematic pattern, which is discussed in relation to the Gould Belt.Six of the 12 detected moving groups do not appear in the classical list of nearby OB associations. This is sometim...

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“…Z99 did not consider it because the Hipparcos proper motion was of insufficient quality, and for this reason we did not observe it. The reported systemic radial velocity is uncertain at the level of 50 km s −1 (B52; Wackerling 1972;Hutchings et al 1975;Duflot et al 1995), so membership remains uncertain.…”

Section: Blaauw 1952 (B52)mentioning

confidence: 99%

Radial velocities of early-type stars in the Perseus OB2 association

Steenbrugge

Bruijne

Hoogerwerf

et al. 2003

A&A

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Abstract. We present radial velocities for 29 B-and A-type stars in the field of the nearby association Perseus OB2. The velocities are derived from spectra obtained with AURELIE, via cross correlation with radial velocity standards matched as closely as possible in spectral type. The resulting accuracy is ∼2-3 km s −1 . We use these measurements, together with published values for a few other early-type stars, to study membership of the association. The mean radial velocity (and measured velocity dispersion) of Per OB2 is 23.5 ± 3.9 km s −1 , and lies ∼15 km s −1 away from the mean velocity of the local disk field stars. We identify a number of interlopers in the list of possible late-B-and A-type members which was based on Hipparcos parallaxes and proper motions, and discuss the colour-magnitude diagram of the association.

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On the Nature of X Persei: Evidence from the 1957 Outburst

Cited by 5 publications

References 21 publications

Phase changes of the Be/X-ray binary X Persei

Phase changes of the Be/X-ray binary X Persei

A [ITAL]Hipparcos[/ITAL] Census of the Nearby OB Associations

Radial velocities of early-type stars in the Perseus OB2 association

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