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Alert Notice 687: LPV Maser campaign extended through October 2020

December 4, 2019

AAVSO Forum threads (scroll to the bottom of a thread for latest posts):
- Campaigns and Observation Reports:
https://www.aavso.org/lpv-maser-2018-campaign
- Long Period Variables: https://www.aavso.org/lpv-maser-2018-campaign-01

Further to AAVSO Alert Notices 645 and 660, Dr. Michael Stroh (Northwestern University) informs us that his SiO maser study on long period variables is being extended through October 2020.

The Mira variable V Cas has been added to the list of targets, bringing the total to 20. Below is a revised list of the targets for this campaign.

Name R.A. (2000) Dec. (2000) Range Spec Type Var Type
TY Cas 00:36:59.42 +63:08:01.7 10.1 - 19.0 V M6-M8 Mira
FI Per 03:54:56.75 +48:36:01.9 14.0 - 17.8 p M7 Mira
SY Mon 06:37:31.34 -01:23:43.0 7.0 - 14.6 V M6e-M9 Mira
FX Mon 06:45:05.60 +09:02:18.5 11.0 - 18.0 p M1-M8 Mira
NSVS 12572573 06:45:14.95 -2:26:35.1 13.5 - <17.0 V M10 Mira
V349 Vul 19:31:10.47 +23:30:33.5 11.4 - 15.2 V M8 Mira
RT Aql 19:38:01.60 +11:43:18.2 7.6 - 14.5 V M6e-M8e(S) Mira
V353 Vul 19:49:22.06 +22:37:39.8 13 - <15.5 V --- Mira
SX Cyg 20:15:33.53 +31:04:20.1 8.2 - 15.2 V M7e Mira
AU Cyg 20:18:32.77 +34:23:20.5 9.5 - 15.3 p M6e-M7e Mira
V1655 Cyg 20:25:24.02 +38:42:35.6 12 - 14.8 I --- Mira
NSVS J2041274+511326 20:41:27.45 +51:13:29.9 11.0 - 13.3 R1 --- Mira
DR Cyg 20:43:41.01 +38:09:56.1 9.3 - <15.5 p M5e Mira
V750 Cyg 20:49:21.17 +50:31:51.3 11.2 - 16.4 V M5ea Mira
W Cep 22:36:27.56 +58:25:34.0 7.02 - 8.5 V M0-M2Iaep+B0/B1 SR supergiant
AL Cep 22:49:16.89 +58:35:07.1 10.9 - 14.5 p M5-M6.5e Mira
VX Cep 22:50:49.45 +64:15:04.7 111.4 - <15.5 p M8 Mira
V Cas 23 11 40.72 +59 41 59.0 6.9 - 13.4 V M5e-M8.5e Mira
V850 Cas 23 37 39.76 +58 50 46.2 12.9 - 15.2 V M5/7e Semiregular
V657 Cas 23 52 04.92 +61 48 12.5 13.9 - <19 V M8.9-10.4III Mira

Dr. Stroh writes: "Our approved Karl G. Jansky Very Large Array (VLA) monitoring campaign [that began] in October of 2018 is continuing through October 2020 and observations from AAVSO would be invaluable. In particular, we believe that the strengths of the SiO maser lines we observe at 43 GHz in the radio are correlated with the phase of the stars in our sample and may allow us to probe the density in the stellar envelopes. Our VLA observations will likely occur about once every 3 weeks, thus AAVSO sampling of targets ranging from 2 to 4 weeks through October 2020] will guide our interpretation of the radio observations."

However, the usual cadence for LPVs is one observation every 10 days, and this cadence is requested by the AAVSO. It is asked that more frequent observations not be made.

Stroh continues: "We prefer Johnson V photometry for all stars to standardize our measurements. If this is not possible, redder filters are preferred (if possible), and are considered a bonus if performed in addition to observations in V since these are very red stars." Visual observations are welcomed and encouraged.

Please see Alert Notice 645 for more details on the campaign.

Charts with comparison stars for each of the targets above may be created using the AAVSO Variable Star Plotter (VSP).

Please submit observations to the AAVSO International Database using the names given in the table.

This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.

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