Astronomy:DW Cancri
File:Cancer constellation map.svg | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Cancer |
| Right ascension | 07h 58m 53.04s[1] |
| Declination | +16° 16′ 45.2″[1] |
| Apparent magnitude (V) | 11.36 - 16.3[2] |
| Characteristics | |
| Evolutionary stage | White dwarf + Red dwarf |
| Variable type | U Gem[2] |
| Astrometry | |
| Radial velocity (Rv) | 38.970486[1] km/s |
| Proper motion (μ) | RA: -25.973[1] mas/yr Dec.: -0.142[1] mas/yr |
| Parallax (π) | 4.8818 ± 0.0395[3] mas |
| Distance | 668 ± 5 ly (205 ± 2 pc) |
| Other designations | |
| Database references | |
| SIMBAD | data |
DW Cancri (DW Cnc) is a cataclysmic variable (CV) star system located in the constellation of Cancer.[1] It is classified as an intermediate polar (IP), a subtype of magnetic CV characterized by a white dwarf primary with a moderately strong magnetic field that channels accretion from a low-mass companion star.[4][5] The system exhibits behaviors typical of VY Scl-type variables, including prolonged low states and occasional brightenings.[6] DW Cnc has an orbital period of approximately 86 minutes, placing it below the period gap for CVs.[4][5]
Discovery
DW Cancri was identified as a potential CV during the Byurakan survey for blue galaxies and quasars, where it appeared as an emission-line object due to strong Balmer series lines in its spectrum.[4] Further spectroscopic confirmation established it as a CV, with initial studies noting its nova-like characteristics and lack of typical dwarf nova outbursts. The system's magnetic nature was inferred from periodic photometric and spectroscopic modulations consistent with an intermediate polar.[4]
Characteristics
DW Cnc is a close binary system consisting of a white dwarf primary and a low-mass main-sequence secondary, likely a red dwarf, from which material is accreted via Roche lobe overflow.[4][5] The white dwarf's magnetic field, estimated to be moderately strong, disrupts the inner accretion disk and funnels material to its magnetic poles, producing characteristic spin-period modulations.[4]
Variability
DW Cnc displays two distinct states: a high state at V ≈ 14.5–15 magnitude and prolonged low states ≈2 magnitudes fainter (V ≈ 16.5–17.5), characteristic of VY Scl stars where reduced mass transfer dims the system.[7][6] In low states, the accretion disk may be depleted, weakening periodic signals like the spin period.[5]
The first observed outburst occurred in 2007, brightening by ≈4 magnitudes to V ≈ 11.36 before fading ≈2.25 magnitudes in 27 hours.[8] More recent observations identified three short high-state outbursts lasting ≈1 day each, with a recurrence time of ≈60 days and amplitude ≈1 magnitude, potentially magnetically gated.[7] These events contrast with the typical quiescence of intermediate polars and suggest episodic mass transfer enhancements.[5]
Kilo-second quasi-periodic oscillations (QPOs) have been detected, with continuous signals over 61 days, interpreted as accretion instabilities or disk modes.[9]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 "DW Cancri". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=DW+Cancri.
- ↑ 2.0 2.1 Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports 61 (1): 80. doi:10.1134/S1063772917010085. Bibcode: 2017ARep...61...80S.
- ↑ European Space Agency; Gaia collaboration (2020), Gaia EDR3, Centre de Donnees Strasbourg (CDS), doi:10.26093/CDS/VIZIER.1350, https://cdsarc.cds.unistra.fr/viz-bin/cat/I/350, retrieved 2026-03-22
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Warner, Brian (2004). "Rapid Oscillations in Cataclysmic Variables". Publications of the Astronomical Society of the Pacific 116 (816): 115. doi:10.1086/381742. Bibcode: 2004PASP..116..115W.
- ↑ 5.0 5.1 5.2 5.3 5.4 Ramírez, S. H.; Segura Montero, O.; Michel, R.; Echevarría, J. (2022). "New Photometry and Spectroscopy of DW Cancri". Revista Mexicana de Astronomia y Astrofisica 58: 47. doi:10.22201/ia.01851101p.2022.58.01.04. Bibcode: 2022RMxAA..58...47R.
- ↑ 6.0 6.1 Rodríguez-Gil, P.; Gänsicke, B. T.; Araujo-Betancor, S.; Casares, J. (2004). "DW Cancri: A magnetic VY SCL star with an orbital period of 86 min". Monthly Notices of the Royal Astronomical Society 349 (1): 367. doi:10.1111/j.1365-2966.2004.07512.x. Bibcode: 2004MNRAS.349..367R.
- ↑ 7.0 7.1 Duffy, C.; Ramsay, G.; Steeghs, D.; Kennedy, M. R.; West, R. G.; Wheatley, P. J.; Dhillon, V. S.; Ackley, K. et al. (2022). "The return of the spin period in DW CNC and evidence of new high state outbursts". Monthly Notices of the Royal Astronomical Society 510 (1): 1002. doi:10.1093/mnras/stab3402. Bibcode: 2022MNRAS.510.1002D.
- ↑ Crawford, T.; Boyd, D.; Gualdoni, C.; Gomez, T.; ((MacDonald, W., II )); Oksanen, A. (2008). "Detection of the First Obeserved Outburst of DW Cancri". Journal of the American Association of Variable Star Observers (Jaavso) 36 (1): 60. Bibcode: 2008JAVSO..36...60C.
- ↑ Uemura, Makoto; Kato, Taichi; Ishioka, Ryoko; Novak, Rudolf; Pietz, Jochen (2002). "Kilo-Second Quasi-Periodic Oscillations in the Cataclysmic Variable DW Cancri". Publications of the Astronomical Society of Japan 54 (2): 299. doi:10.1093/pasj/54.2.299. Bibcode: 2002PASJ...54..299U.
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