AAVSO: American Association of Variable Star Observers

Proposal #74

Proposer (15617) Barber Observatory University of Illinois Springfield (jmart5@uis.edu) obscode: UIS01
Assigned To(3663) Dirk Terrell
Date SubmittedAug. 4, 2017

Stars classified "Be" are stars with B spectral types AND conspicuous hydrogen and helium emission lines. Many of these stars are main sequence stars that exhibit low level irregular variability (~0.1 mag) and changes in the profiles of their emission lines. Many Be stars a known to unpredictably turn off and then later re-estabilsh their emission. There is some evidence that the phenomenon is associated with binary but it cannot be conclusively stated that all Be stars are binary. The best hypothesis is that the emission lines are produced in circumstellar gas, probably in the form of an excretion disk formed from the radiatively driven stellar wind. Although there have been may theoretical attempts to comprehensively model the Be phenomenon there is no comprehensive theoretical model for the disks or how they form and dissipate.

Be stars have been a popular target among non-professionals doing spectroscopy. See the Be Star Spectra Database (BeSS; http://basebe.obspm.fr/basebe/)
For the last 10+ years the University of Illinois Springfield Barber Observatory has conducted long term spectroscopic monitoring of several Be Stars at high spectroscopic resolution of the full visual range (https://sites.google.com/a/uis.edu/uis-barber-research-observatory/research-programs/be-stars/).
While spectroscopic databases exist covering these stars, the photometry is thin, particularly for the bright Be stars which are easiest for non-pros to take spectra of and are also too bright for most telescopes to monitor photometrically. Photometry is useful because it can give useful information about the change in overall energy output and effective surface temperature of the star, which is more difficult to obtain exclusively from spectroscopy.
At the UIS Barber Observatory we have conducted a PEP photometry program of these stars. But our coverage and sampling of them has been sparse and irregular. The community could benefit from a more uniform dataset that BSM monitoring could provide.
Many Be stars are listed in the BSM Epoch Photometry Database but they have few data points and none more recent than several years ago.

The time scale of changes in Be stars is usually measured in months or years. We propose monthly or bimonthly Johnson B and V photometry from BSM images over an indefinite period going forward. I propose to do this as a public service to the bright Be Star community, making the data immediately available in WebObs (with NO proprietary period) as soon as it is reduced.

Target RA (H.HH) Dec (D.DD) Magnitude Telescope Observation Frequency Expiration Date Proprietary Term
Psi Per 3.608161 48.19264 4.17–4.36 No
11 Cam 5.102347 58.97236 5.08 No
Zeta Tau 5.627414 21.14256 2.8–3.17 No
Kappa Dra 12.558042 69.78822 3.82–4.01 No
Tet CrB 15.548828 31.35914 4.06–4.33 No
V2048 Oph 18.004389 4.36861 4.55–4.85 No
59 Cyg 20.997100 47.52094 4.49–5.07 No
Pi Aqr 22.421278 1.37750 4.42–4.7 No
Beta Psc 23.064611 3.82000 4.51–4.55 No


(3663) Dirk Terrell — Aug. 14, 2017, 11:37 a.m.

The TAC suggests a weekly cadence and UBVRI filters.

(15617) Barber Observatory University of Illinois Springfield — Aug. 14, 2017, 11:56 a.m.

Thanks. I'll take weekly in all filters.
I have a concern though that I may not be able to measure the photometry for U in VPHOT and that there may not be comparison stars/ sequences for U developed for these targets.
The other filters have no such concerns.

(2911) Michael Nicholas — Sept. 13, 2017, 8:23 p.m.

Zeta Tau=123 Tau=000-BBJ-767

(2911) Michael Nicholas — Sept. 13, 2017, 8:27 p.m.

Kap Dra=5 Dra=000-BCV-882

(2911) Michael Nicholas — Sept. 13, 2017, 8:33 p.m.

Beta Psc=4 Psc=000-BCR-153

(15617) Barber Observatory University of Illinois Springfield — June 21, 2018, 11:44 a.m.

Please change the centering of the images for Pi Aqr to 22h24m26s +01d02m21s so that it includes both the target and HD 212318 which is 53.4 arcmin to the SW

(15617) Barber Observatory University of Illinois Springfield — July 10, 2018, 7:42 p.m.

I am now getting two sets of images for Pi Aqr each night. One centered on Pi Aqr (22.4212777778, +1.3775) and the other centered as directed on the comment on June 21 (22h24m26s +01d02m21s). Please discontinue the first one (centered on the star) and continue to image centered on the coordinates 22h24m26s +01d02m21s.

(15617) Barber Observatory University of Illinois Springfield — Jan. 2, 2020, 9:39 p.m.

I need the center for images for Psi Per updated please.
The last two sets of images the comparison (which is normally on the edge of the field with Psi Per centered) was off the edge. Could be rotation of the field or bad pointing the caused it. It happened twice in a row so I want to suggest it will work better to center the field at RA 03:34:30 Dec +48:13:30 putting the image center roughly halfway between the target and the comparison.
Thank you.

Comments on this proposal are closed.