DY Persei variable

DY Persei variables are a subclass of R Coronae Borealis (R CrB) variables. They are carbon-rich asymptotic giant branch (AGB) stars that exhibit pulsational variability of AGB stars and irregular fades similar to R CrB stars.

The star DY Persei is the prototype of this tiny class of variable stars. Only DY Persei itself was known in out galaxy until 2008 when systematic catalogue searches for R CrB variables discovered a 17th magnitude (at maximum) example.^[1] Since then automated searches have confirmed another four, including one of magnitude 5.9 at maximum.^[2] There are also several candidates that have not yet been observed to fade, and several DY Per stars in the Large Magellanic Cloud.^[3]

Although DY Persei variables have been considered a subset of the R CrB variables because of their irregular fades and carbon-rich spectra, they may simply be an unusual type of Carbon star unrelated to the more massive and more luminous R CrB variables. The fades may be caused by obscuring ejection events rather than carbon condensation in the atmospheres of the stars.^[2]

References

↑ Tisserand, P.; Marquette, J. B.; Wood, P. R.; Lesquoy, É.; Beaulieu, J. P.; Milsztajn, A.; Hamadache, C.; Afonso, C.; Albert, J. N.; Andersen, J.; Ansari, R.; Aubourg, É.; Bareyre, P.; Charlot, X.; Coutures, C.; Ferlet, R.; Fouqué, P.; Glicenstein, J. F.; Goldman, B.; Gould, A.; Gros, M.; Haissinski, J.; De Kat, J.; Le Guillou, L.; Loup, C.; Magneville, C.; Maurice, É.; Maury, A.; Moniez, M.; et al. (2008). "R Coronae Borealis stars in the Galactic bulge discovered by EROS-2". Astronomy and Astrophysics. 481 (3): 673. arXiv:0801.1680. Bibcode:2008A&A...481..673T. doi:10.1051/0004-6361:20078814.
1 2 Miller, A. A.; Richards, J. W.; Bloom, J. S.; Cenko, S. B.; Silverman, J. M.; Starr, D. L.; Stassun, K. G. (2012). "Discovery of Bright Galactic R Coronae Borealis and Dy Persei Variables: Rare Gems Mined from Acvs". The Astrophysical Journal. 755 (2): 98. arXiv:1204.4181. Bibcode:2012ApJ...755...98M. doi:10.1088/0004-637X/755/2/98.
↑ Tisserand, P.; Wood, P. R.; Marquette, J. B.; Afonso, C.; Albert, J. N.; Andersen, J.; Ansari, R.; Aubourg, É.; Bareyre, P.; Beaulieu, J. P.; Charlot, X.; Coutures, C.; Ferlet, R.; Fouqué, P.; Glicenstein, J. F.; Goldman, B.; Gould, A.; Gros, M.; De Kat, J.; Lesquoy, É.; Loup, C.; Magneville, C.; Maurice, É.; Maury, A.; Milsztajn, A.; Moniez, M.; Palanque-Delabrouille, N.; Perdereau, O.; Rich, J.; et al. (2009). "New Magellanic Cloud R Coronae Borealis and DY Persei type stars from the EROS-2 database: The connection between RCBs, DYPers, and ordinary carbon stars". Astronomy and Astrophysics. 501 (3): 985. arXiv:0905.3224. Bibcode:2009A&A...501..985T. doi:10.1051/0004-6361/200911808.

Variable stars

Pulsating

Cepheids and cepheid-like	Classical Type II (BL Herculis, W Virginis) RR Lyrae Delta Scuti Rapidly oscillating Ap SX Phoenicis

Blue-white with early spectra	Alpha Cygni Beta Cephei Slowly pulsating B PV Telescopii

Long-period and semiregular	Mira Semiregular Slow irregular

Other	Gamma Doradus RV Tauri Solar-like oscillations White dwarf

Eruptive

Protostar	FU Orionis Herbig Ae/Be Orion

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

Cataclysmic

Rotating

Non-spherical	Rotating ellipsoidal

Stellar spots	BY Draconis FK Comae Berenices

Magnetic fields	Alpha² Canum Venaticorum Pulsar SX Arietis

Eclipsing

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