Zero polarisation standards
NEW:
Highly accurate DIPOL measurements of low-polarisation stars are found in
Piirola et al. 2020, A&A 635, A46
High-precision polarimetry of nearby stars (d < 50 pc)
A selection is to be added to our ZP standard star list (TBD) and a few are listed below in the format of TCS catalogs. Note the high proper motions and the bright V magnitude.
HD4813 00 50 07.59 -10 38 39.6 2000.0 -0.2269 -0.2298 5.19 P=0.0006%
HD18144 02 55 17.41 +16 18 33.1 2000.0 0.2043 -0.0466 6.9 P=0.0008%
HD42182 06 09 35.91 +05 40 08.1 2000.0 0.0588 0.0465 8.38 P=0.0028%
HD65629 07 59 53.39 +09 53 55.3 2000.0 0.1239 -0.1510 7.8 P=0.0014%
HD191195 20 06 13.85 +53 09 56.5 2000.0 0.2133 0.2551 5.7 P=0.0039%
New and fainter (13 mag < R < 17 mag) zero-pol standards may be found from the source list of
white dwarfs observed with RoboPol by Zejmo et al. 2017, MNRAS 464, 1294. See
online table .
The below catalogue can be loaded to the TCS by typing read-cat zpol.cat in the TCS terminal.
Name
TCSTGT |
RA (2000) |
DEC (2000) |
V |
B-V |
Sp. Type |
PB (%) |
Comment |
HD 12021
HD12021
|
01 57 56.11 |
-02 05 58.2 |
8.86 |
-0.10 |
B7 |
0.112 ± 0.025 |
|
HD 14069
HD14069
|
02 16 45.16 |
07 41 11.1 |
9.00 |
|
A0 |
0.111 ± 0.036 |
|
HD 21447
HD21447
|
03 30 00.21 |
55 27 07.0 |
5.10 |
+0.04 |
A1 IV |
0.017 ± 0.030 |
ND filter #5 (1 % transmission) |
G191B2B
G191B2B
|
05 05 30.62 |
52 49 54.0 |
11.78 |
-0.30 |
DA1 |
0.090 ± 0.048 |
Faint. More than 1 cycle a 15 min
needed on Turpol. |
HD 64299
HD64299
|
07 52 25.55 |
-23 17 45.9 |
10.15 |
+0.09 |
A2 V |
0.151 ± 0.032 |
|
HD 94851
HD94851
|
10 56 44.17 |
-20 39 51.6 |
9.10 |
|
B9 |
0.057 ± 0.018 |
ND filter #6 (open) |
GD 319
GD319
|
12 50 04.49 |
55 06 02.5 |
12.32 |
+0.04 |
DA |
0.045 ± 0.047 |
Faint. More than 1 cycle a 15 min
needed on Turpol.
NB Binary, separation ~2.6" |
BD +33 2642
BDp33_2642
|
15 51 59.86 |
32 56 54.8 |
10.84 |
-0.17 |
B2 IV |
0.145 ± 0.029 |
ND filter #6 (open) |
HD 154892
HD154892
|
17 07 41.38 |
15 12 37.6 |
8.00 |
|
F8 V |
0.050 ± 0.030 |
|
BD +32 3739
BDp32_3739
|
20 12 02.11 |
32 47 43.5 |
9.31 |
+0.20 |
A6 V |
0.039 ± 0.021 |
ND filter #6 (open) |
BD +28 4211
BDp28_4211
|
21 51 11.07 |
28 51 51.8 |
10.53 |
-0.34 |
Op |
0.063 ± 0.023 |
ND filter #6 (open) |
HD 212311
HD212311
|
22 21 58.55 |
56 31 52.8 |
8.10 |
+0.08 |
A0 V |
0.028 ± 0.025 |
ND filter #1 (50% transmission) |
Stars suitable for the NOT, taken from The Hubble Space Telescope atlas, see Turnshek et al. 1990, AJ 99, 1243.
Finding charts from the Digital Sky Survey are obtained by clicking on the star names. These have North up and East left, are centred on the star, and the field size is 6.5 arc minutes (i.e. ALFOSC field with no calcite plate in the beam).
Additional standard stars
- Blinov, D, et al. 2023 The RoboPol sample of optical polarimetric standards ,
2023, A&A 677, 144
The visibility plot of today:
Minimum observing altitude when lower hatch closed: 35 degrees. 
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