TY - JOUR

T1 - Optical linear polarization of helium-rich white dwarfs sample with the RoboPol polarimeter

AU - Słowikowska, Aga

AU - Krzeszowski, Krzysztof

AU - Zejmo, Michał

AU - Blinov, Dmitry

AU - Reig, Pablo

PY - 2018/10/1

Y1 - 2018/10/1

N2 - We performed observations of 28 white dwarfs (WDs) as the second part of our WD optical linear polarimetric survey. Our study shows that highly linear polarized WDs are very rare. However, three systems,WD1336+123 (DB+dM4), WD1415+234 (DBA) and WD1619+123 (DA+dG0), show linear polarization degree higher than 1 per cent. In particular,WD1415+234 with polarization degree ~2.6 per cent is the strongest polarizedWDin our total sample of 101 objects. We found that the median polarization degree of isolated DA WDs and DB WDs is similar but lower than the median polarization of isolated DC WDs. The DB WDs in binaries seem to be more polarized than binaries containing DA+dM or double-degenerated systems (DDSs) with DA component. Additionally, we present for the first time, the measurements of optical linear polarization of both components in two common proper motion binary systems (CPMB) systems: WD1336+123 and the Sirius-like system WD2129+000. Because the vast majority of WDs have very low polarization degree (<0.5 per cent), they can be used as faint linear polarization standards. Our sample covers SDSS r magnitude range from 13 to 17 and right ascension range from 13h to 24h, with the extension from 1h to 3h.

AB - We performed observations of 28 white dwarfs (WDs) as the second part of our WD optical linear polarimetric survey. Our study shows that highly linear polarized WDs are very rare. However, three systems,WD1336+123 (DB+dM4), WD1415+234 (DBA) and WD1619+123 (DA+dG0), show linear polarization degree higher than 1 per cent. In particular,WD1415+234 with polarization degree ~2.6 per cent is the strongest polarizedWDin our total sample of 101 objects. We found that the median polarization degree of isolated DA WDs and DB WDs is similar but lower than the median polarization of isolated DC WDs. The DB WDs in binaries seem to be more polarized than binaries containing DA+dM or double-degenerated systems (DDSs) with DA component. Additionally, we present for the first time, the measurements of optical linear polarization of both components in two common proper motion binary systems (CPMB) systems: WD1336+123 and the Sirius-like system WD2129+000. Because the vast majority of WDs have very low polarization degree (<0.5 per cent), they can be used as faint linear polarization standards. Our sample covers SDSS r magnitude range from 13 to 17 and right ascension range from 13h to 24h, with the extension from 1h to 3h.

KW - Polarization

KW - Stars: individual: WD1336+123

KW - Stars: individual: WD1415+234

KW - Stars: individual: WD1619+123

KW - Stars: individual: WD2129+000

KW - White dwarfs

UR - http://www.scopus.com/inward/record.url?scp=85051510006&partnerID=8YFLogxK

U2 - 10.1093/mnras/sty1745

DO - 10.1093/mnras/sty1745

M3 - Article

AN - SCOPUS:85051510006

VL - 479

SP - 5312

EP - 5324

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 4

ER -