Monitoring requested for developing planetary systems dust p

[PTS]

Monitoring requested for developing planetary systems dust production study

Dr. George Rieke (University of Arizona) and colleagues have
requested AAVSO assistance in monitoring four stars with developing
planetary systems. The targets are RZ Psc, HD 15407A, V488 Per, and
HD 23514. This campaign is similar to the one conducted in 2013 (see
AAVSO Alert Notice 482).

Dr. Rieke writes: "We have obtained 130 hours of time on the Spitzer
Space Telescope to continue monitoring planetary debris disks for
variability. We are asking for help from AAVSO for this program.

"Debris disks - systems of dust and particles associated with
planetary systems - are most easily observed from the infrared
emission of their dust when it is warmed by the star, although a
small number have also been observed in scattered emission, mostly
by HST. They are a powerful approach to understanding planetary
systems and their evolution because they can be detected at all
phases of the development of a planetary system, and to large
distances. Hundreds of them are known from IRAS, ISO, Spitzer,
WISE, and Herschel. Among these hundreds, there are about a dozen
where there is evidence that massive collisions are occurring right
now, collisions that are building planets in much the same way that
a large body added most of its mass to that of the Earth and created
the Moon as a byproduct when the Solar System was young... A paper
from Science describing the most thoroughly studied such system [may
be found at the link given at the end of this notice]. A second
paper on a larger number of variable debris disks has been submitted
and we have received the referee report; the necessary revisions
will be complete soon for final publication.

"A key part of our program is to obtain optical photometry of the
same stars that we are observing in the infrared under the Spitzer
program. The optical data are needed to verify that any changes we
see in the infrared are not just driven by changes in the brightness
of the star, but are truly due to changes in the structure or dust
content of the debris disk. AAVSO observers provided this support
for our previous program, as summarized in the paper about to go
back to the journal after refereeing; all of those who contributed
data are co-authors of the paper.

"We request AAVSO to take similar observations for the new program.
The table below lists the stars we are observing and basic
information about them, and the two visibility windows for Spitzer
(all observations will be obtained within the range of dates
indicated)."

This campaign begins immediately and runs in two segments, now
through May and September through December.

Target SpT Age Vmag R.A. (2000) Dec. (2000) Spitzer visibility windows in 2015
(Myr) First segment Second segment
RZ Psc KOIV 35 11.29 01 09 42.06 +27 57 01.95 Mar 14-Apr 24 Oct 10-Nov 20
HD 15407A F5V 80 6.95 02 30 50.66 +55 32 54.2 Apr 5-May 24 Nov 7-Dec 28
V488 Per KOIV 60 12.83 03 28 18.68 +48 39 48.2 Apr 17-May 30 Nov 15-Dec 31
HD 23514 F5V 150 9.43 03 46 38.40 +22 55 11.2 Apr 18-May 26 Nov 13-Dec 23

Dr. Rieke and we recognize that all of these targets will be very
near conjunction between now and the end of May, and so may be
extremely difficult if not impossible to observe from the ground
until nearly the end of the first segment. However, they are all
observable with Spitzer during the first segment because of its
orbit. Any morning observations that you are able to make will be
greatly appreciated! During the second segment, the stars will be
much better placed for observations from the ground; these
observations will also be greatly appreciated. We will issue a
Special Notice to remind observers before the second segment begins.

Observations in V are requested, with a S/N of about 100 so that the
accuracy will be 1-2%. Observations should begin at least one week
before the visibility window opens and finish one week after the
window closes.

No specific comparison stars are assigned for each target, but
observers are requested to use only those in the sequences available
via the AAVSO Variable Star Plotter (VSP, http://www.aavso.org/vsp).
It is essential that observers report the comparison stars used when
submitting their observations to the AAVSO.

Observations should be submitted to the AAVSO International Database
using the names RZ PSC, HD 15407A, HD 23514, and V488 PER, respectively.

The paper from Science may be found at:
http://www.aavso.org/sites/default/file ... mpacts.pdf

This campaign is being followed on the AAVSO Observing Campaigns page
(http://www.aavso.org/observing-campaigns).

This AAVSO Alert Notice was compiled by Elizabeth Waagen.

----------------------------------
SUBMIT OBSERVATIONS TO THE AAVSO

Information on submitting observations to the AAVSO may be found at:
http://www.aavso.org/webobs

ALERT NOTICE ARCHIVE AND SUBSCRIPTION INFORMATION

An Alert Notice archive is available at the following URL:
http://www.aavso.org/alert-notice-archive

Subscribing and Unsubscribing may be done at the following URL:
http://www.aavso.org/observation-notifi ... ertnotices