Study of the low-amplitude Z Cam star IX Vel

Katô, Takeo

doi:10.48550/arxiv.2111.15145

Cited by 2 publications

(4 citation statements)

References 17 publications

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“…In figure 14, we show the trend of mean magnitudes (averaged in flux) as we did for IX Vel (Kato 2021b) and ST Cha . The result shows that the 2019-2020 standstill was not brighter than the dwarf nova-type states (IW And-type states) before and after this.…”

Section: Are Standstills Brighter Than Dwarf Nova-type States?mentioning

confidence: 96%

“…The 22.44 d period in apparently referred to these low-amplitude dwarf nova-type variations. Although such low-amplitude dwarf nova-type variations are also seen in IX Vel(Kato 2021b), the cycle length in ASAS J071404+7004.3 is longer compared to IX Vel with 13-20 d and the profile is different in that variations in ASAS J071404+7004.3 tend to have slower rise and steeper decline as seen in the third panel of figure 2. This feature was interpreted as "inside out" (outburst) in.The main reason why reached an inadequate classification was that they only consulted the relatively old literature when referring to IW And stars.…”

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confidence: 87%

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Analysis of the IW And star ASAS J071404+7004.3

Katô¹,

Kasai²,

Павленко³

et al. 2022

Preprint

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We made a time-resolved photometric campaign of the bright cataclysmic variable ASAS J071404+7004.3 in 2020. , arXiv/2109) recently published time-resolved optical spectroscopy, Xray observations and long-and short-term optical variations. Although their results were correct in many parts, they classified ASAS J071404+7004.3 as a VY Scl-type novalike object. By comparing the ASAS-SN data of this object and the IW And-type object HO Pup, we showed that their type classification was incorrect. ASAS J071404+7004.3 showed outbursts from a standstill followed by shallow dips, which is the defining characteristic of an IW And star. This object predominantly showed states with low-amplitude dwarf nova-type oscillations, some of which could be identified as the "heartbeat"-type state as a variety of the IW And-type phenomenon. The low state described by was not a true low state of a VY Scl star, but a dwarf nova-type state with increased outburst amplitudes. Both ground-based (our campaign) and TESS observations detected orbital variations whose periods [0.136589(5) d by the ground-based campaign and 0.1366476(3) d by the TESS data] are in very good agreement with the one obtained by radial-velocity studies by . The standstill in 2019-2020 in ASAS J071404+7004.3 was not brighter than its dwarf nova-type states. The brightest moment of this object occurred when the amplitudes of dwarf novatype variations were large, which challenges the widely accepted interpretation that standstills in Z Cam stars occur when the mass-transfer rates are high.

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Section: Are Standstills Brighter Than Dwarf Nova-type States?mentioning

confidence: 96%

mentioning

confidence: 87%

Analysis of the IW And star ASAS J071404+7004.3

Katô¹,

Kasai²,

Павленко³

et al. 2022

Preprint

Self Cite

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“…The spectra were obtained with slit widths of 1.3 in the UVB arm, 1.2 in the VIS arm, and 1.2 in the NIR arm, using an exposure time of 20 s for each arm. The data were reduced using the Reflex pipeline (Freudling et al 2013) and a telluric correction was performed using molecfit (Smette et al 2015;Kausch et al 2015).…”

Section: X-shootermentioning

confidence: 99%

“…The same light curves were later modelled by Linnell et al (2007), who interpreted the minimum at orbital phase 0.0 as a partial eclipse of the rim of the accretion disc by the secondary. Kato (2021) studied the long-term variability of IX Vel using All-Sky Automated Survey (ASAS-3;Pojmanski 1997) and All-Sky Automated Survey for Supernovae (ASAS-SN; Shappee et al 2014;Kochanek et al 2017) observations, and found that the data show small amplitude variations similar to dwarf novae outbursts and also standstills, suggesting that IX Vel is a low-amplitude Z Cam star, in other words a dwarf nova alternating between states of outbursting activity and states of high constant brightness (standstills) similar to those in NLs.…”

Section: Introductionmentioning

confidence: 99%

Structure of the accretion flow of IX Velorum as revealed by high-resolution spectroscopy

Kára,

Schmidtobreick,

Pala

et al. 2023

A&A

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Context. Several high mass-transfer cataclysmic variables show evidence of outflow from the system, which could play an important role in their evolution. We investigate the system IX Vel, which was proposed to show similar characteristics. Aims. We study the structure of the IX Vel system, particularly the structure of its accretion flow and accretion disc. Methods. We used high-resolution time-resolved spectroscopy to construct radial velocity curves of the components in IX Vel. We computed Doppler maps of the system, which we used to estimate the temperature distribution maps. Results. We have improved the spectroscopic ephemeris of the system and its orbital period Porb = 0.19392793(3) d. We constructed Doppler maps of the system based on hydrogen and helium emission lines and the Bowen blend. The maps show features corresponding to the irradiated face of the secondary star, the outer rim of the accretion disc, and low-velocity components located outside the accretion disc and reaching towards L3. We constructed a temperature distribution map of the system using the Doppler maps of Balmer lines. Apart from the features found in the Doppler maps, the temperature distribution map shows a region of high temperature in the accretion disc connecting the expected position of a bright spot and the inner parts of the disc. Conclusions. We interpret the low-velocity emission found in the Doppler map as emission originating in the accretion disc wind and in an outflow region located in the vicinity of the third Lagrangian point L3. This makes IX Vel a member of the RW Sex class of cataclysmic variables.

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Study of the low-amplitude Z Cam star IX Vel

Cited by 2 publications

References 17 publications

Analysis of the IW And star ASAS J071404+7004.3

Analysis of the IW And star ASAS J071404+7004.3

Structure of the accretion flow of IX Velorum as revealed by high-resolution spectroscopy

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