Double periodic variable

A Double Periodic Variable (DPV) is a type of binary star. As the name implies, the systems vary in brightness not only due to eclipses of one star by the other, but also on a cycle of roughly 33 times longer than the orbit. The star gaining mass from the other has a thick disk of material surrounding it, and the systems apparently lose mass cyclically into the interstellar medium over time. The cause for the secondary longer variability still is not established, but it has been proposed to be linked to a magnetic dynamo in the donor (mass transferring) star. A famous example is β Lyrae. The stars are rare, with 21 systems found in the Galaxy and more than 170 in the Magellanic Clouds (Abril 2016).

List

Catalogues of Double Periodic Variables are given by Mennickent, Otero and Kołaczkowski (2016), Pawlak et al. (2013) and Poleski et al. (2010). Some few examples are given below.

This list is incomplete; you can help by adding missing items. (April 2016)

The following list contains selected double periodic variables that are of interest to amateur or professional astronomy. Unless otherwise noted, the given magnitudes are in the V-band.

Star	Maximum magnitude	Minimum magnitude	Eclipse period (in days)	Spectral type
V393 Scorpii	7.39	8.31	7.72	B3III
AU Monocerotis	8.20	9.16	11.11	B5IV+F8-G0II-III

References

Mennickent, R.E., 2017, Long Photometric Cycles in Hot Algols, Serbian Astronomical Journal 194, 1
Schleicher, D., Mennickent, R.E., 2017, A dynamo mechanism as the potential origin of the long cycle in double periodic variables, Astronomy and Astrophysics, 602, A109.
Mennickent, R.E., Otero, S., Kolaczkowski, Z., 2016, Interacting binaries W Serpentids and double periodic variables, Monthly Notices of the Royal Astronomical Society, Volume 455, Issue 2, p. 1728-1745.
Otero, S.A., Watson, C., Wils, P., Variable Star Type Designations in the VSX. AAVSO Website. American Association of Variable Star Observers. Retrieved 11 May 2014.
Pawlak, M., et al. 2013, Eclipsing Binary Stars in the OGLE-III Fields of the Small Magellanic Cloud, Acta Astronomica, vol 63, no 3, p. 323-338.
Poleski, R. et al. 2010, The Optical Gravitational Lensing Experiment. The OGLE-III Catalog of Variable Stars. X. Enigmatic Class of Double Periodic Variables in the Large Magellanic Cloud, Acta Astronomica, vol 60, no 3, p. 179-196.
Mennickent, R.E., Pietrzynski, G., Diaz, M, Gieren, W., 2003, Double-periodic blue variables in the Magellanic Clouds, Astronomy and Astrophysics, v.399, p. L47-L50. (Discovery paper).

Variable stars

Pulsating

Cepheids and cepheid-like	Type I (Classical cepheids, Delta Scuti) Type II (BL Herculis, W Virginis, RV Tauri) RR Lyrae Rapidly oscillating Ap SX Phoenicis
Blue-white with early spectra	Alpha Cygni Beta Cephei Slowly pulsating B-type PV Telescopii Blue large-amplitude pulsator
Long-period	Mira Semiregular Slow irregular
Other	Gamma Doradus Solar-like oscillations White dwarf

Eruptive

Protostar and PMS	Herbig Ae/Be Orion FU Orionis T Tauri
Giants and supergiants	Luminous blue variable R Coronae Borealis (DY Persei) Yellow hypergiant
Eruptive binary	Double periodic FS Canis Majoris RS Canum Venaticorum
Other	Flare Gamma Cassiopeiae Lambda Eridani Wolf–Rayet