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SRG/eROSITA X-ray selected cataclysmic variable candidates observed in SDSS-V DR20
J. Brink, A. D. Schwope, K. G. Pradeep +35
We report on the spectroscopic observations obtained during SDSS-V DR20 of accreting compact binaries (ACB), specifically the cataclysmic variables (CVs), that were identified as l…
Unveiling the period-bounce population of cataclysmic variables: Spectroscopic and time-domain follow-up of eROSITA-selected candidates
S. Hernández-Díaz, B. Stelzer, A. Schwope +9
During their secular evolution, cataclysmic variable stars (CVs) evolve toward shorter orbital periods () until reaching a minimum near min, after…
A modest change in magnetic braking at the fully convective boundary explains cataclysmic variable evolution
Joaquín A. Barraza-Jorquera, Matthias R. Schreiber, Stuart Littlefair +2
Context. For decades, reproducing the orbital period distribution of non-magnetic Cataclysmic Variables (CVs) seemed to require a drastic decrease, usually termed disruption, of an…
A Catalogue of Orbital Periods of Cataclysmic Variables and Candidates from TESS Observations
Meryem K. Dağ, Simone Scaringi, Kieran O'Brien +21
We present a systematic analysis of 2544 cataclysmic variable systems and related candidates observed by the Transiting Exoplanet Survey Satellite (TESS), with the aim of compiling…
The optical photometric and spectroscopic periodicities of the cataclysmic variable SRGt 062340.2-265751
J. Brink, D. A. H. Buckley, M. Veresvarska +10
We report on optical spectroscopic and photometric follow-up observations of the eROSITA discovered transient SRGt 062340.2-265751 and show that it displays the characteristics of…
A systematic search for orbital periods of polars with TESS. Methods, detection limits, and results
Santiago Hernández-Díaz, Beate Stelzer, Axel Schwope +1
Context. Determining the orbital periods of cataclysmic variable stars (CVs) is essential for confirming candidates and for the understanding of their evolutionary state. The Trans…
eROSITA-selection of new period-bounce Cataclysmic Variables: First follow-up confirmation using TESS and SDSS
Daniela Muñoz-Giraldo, Beate Stelzer, Axel Schwope +3
Between 40 and 80 of cataclysmic variables (CVs) are expected to have evolved past the period-minimum and contain a degenerate donor. However, observational surveys for CVs…
A star-by-star correspondence between X-ray activity and rotation in the young open cluster NGC 2516 with eROSITA
Dario J. Fritzewski, Sydney A. Barnes, Samet Ok +2
The coronal soft X-ray emission of cool stars, especially when taken in combination with their measured rotation periods, offers insights into their levels of magnetic activity and…
Double White Dwarf Binaries in SDSS-V DR19 : A catalog of DA white dwarf binaries and constraints on the binary population
Gautham Adamane Pallathadka, Vedant Chandra, Nadia L. Zakamska +17
The fifth-generation Sloan Digital Sky Survey (SDSS-V) includes the first large-scale spectroscopic survey of white dwarfs (WDs) in the era of Gaia parallaxes. SDSS-V collects mult…
A Large Catalog of DA White Dwarf Characteristics Using SDSS and Gaia Observations
Nicole R. Crumpler, Vedant Chandra, Nadia L. Zakamska +12
We present a catalog of 8545 and 19,257 unique DA white dwarfs observed in SDSS Data Release 19 and previous SDSS data releases, respectively. This is the largest catalog of both s…
Double White Dwarf Binaries in SDSS-V DR19 : The discovery of a rare DA+DQ white dwarf binary with 31 hour orbital period
Gautham Adamane Pallathadka, Vedant Chandra, Boris T. Gansicke +13
Binaries of two white dwarfs (WDs) are an important class of astrophysical objects that are theorized to lead to Type Ia supernovae and are also used to gain insight into complex p…
X-ray and Optical Analysis of the Prototype Polar AN UMa
S. Ok, M. Yardimci, B. Kalomeni +1
We present a long-term optical and X-ray photometric study of AN UMa, one of the prototypical polar-type cataclysmic variables, tracing more than 34 years of its accretion history.…
PolarCat: Catalog of polars, low-accretion rate polars, and candidate objects
Axel D. Schwope
Polars and low-accretion rate polars (LARPs) are strongly magnetic cataclysmic variables. Mediated by the magnetic field of the white dwarf, their spin and binary orbit are (mostly…
A first systematic characterization of cataclysmic variables in SRG/eROSITA surveys
Axel Schwope, Kira Knauff, Jan Kurpas +4
(abridged) We present an account of known cataclysmic variables (CVs) that were detected as X-ray sources in eROSITA X-ray surveys and have Gaia DR3 counterparts. We address standa…
Unveiling the nature of two dwarf novae: CRTS J080846.2+313106 and V416 Dra
Arti Joshi, Márcio Catelan, Simone Scaringi +8
We present the analysis of optical photometric and spectroscopic observations of two non-magnetic cataclysmic variables, namely CRTS J080846.2+313106 and V416 Dra. CRTS J080846.2+3…
Cataclysmic variables from Sloan Digital Sky Survey -- V (2020-2023) identified using machine learning
Keith Inight, Boris T. Gänsicke, Axel Schwope +16
SDSS-V is carrying out a dedicated survey for white dwarfs, single and in binaries, and we report the analysis of the spectroscopy of 504 cataclysmic variables (CVs) and CV candida…
The cataclysmic variable orbital period gap: More evident than ever
Matthias R. Schreiber, Diogo Belloni, Axel D. Schwope
Recently, large and homogeneous samples of cataclysmic variables (CVs) identified by the Sloan Digital Sky Survey (SDSS) were published. In these samples, the famous orbital period…
Cataclysmic variables around the period-bounce: An eROSITA-enhanced multi-wavelength catalog
Daniela Muñoz-Giraldo, Beate Stelzer, Axel Schwope
Context. Cataclysmic variables with degenerate donors which have evolved past the period minimum, also known as period-bouncers, are predicted to make up a great portion of the cat…
MACHO 311.37557.169: A VY Scl star
H. Worpel, A. D. Schwope, I. Traulsen +1
Optical surveys, such as the MACHO project, often uncover variable stars whose classification requires followup observations by other instruments. We performed X-ray spectroscopy a…
IGR J19552+0044: A new asynchronous short period polar: "Filling the gap between intermediate and ordinary polars"
G. Tovmassian, D. Gonzalez-Buitrago, J. Thorstensen +23
Based on XMM--Newton X-ray observations IGR J19552+0044 appears to be either a pre-polar or an asynchronous polar. We conducted follow-up optical observations to identify the sourc…
Probing the accretion processes in soft X-ray selected polars
I. Traulsen, K. Reinsch, A. D. Schwope
High-energy data of accreting white dwarfs give access to the regime of the primary accretion-induced energy release and the different proposed accretion scenarios. We perform XMM-…
On the ephemeris of the eclipsing polar HU Aquarii
A. D. Schwope, B. D. Thinius
The magnetic cataclysmic variable HU Aquarii displayed pronounced quasi-periodic modulations of its eclipse timing. These were interpreted in terms of the light-travel time (LTT) e…
The giant planet orbiting the cataclysmic binary DP Leonis
K. Beuermann, J. Buhlmann, J. Diese +13
Planets orbiting post-common envelope binaries provide fundamental information on planet formation and evolution, especially for the yet nearly unexplored class of circumbinary pla…
A long-term optical and X-ray ephemeris of the polar EK Ursae Majoris
K. Beuermann, J. Diese, S. Paik +4
We searched for long-term period changes in the polar EK UMa using new optical data and archival X-ray/EUV data. An optical ephemeris was derived from data taken remotely with the…