Snow at McDonald Observatory

Todd Watson and the 82 inch telescope at McDonald Observatory

Target Stars Summary

Here's a quick summary of our target stars:

1)  HS0507+0434B has proven to be very much like EC14012-1446 and GD358.  We 
have identified multiplets associated with several of the modes, plus we have 
seen power grow as we have been observing:)  Take a look at the figure in the
blog. You can see how HS0507 has evolved during the run.
2) HL Tau 76 is always interesting.  Here we are seeing a wide range of 
pulsation frequencies - from 900 to 2500 microHz, some of which are 
multiplets. Some of these "modes" appear to comprise a series that is 
equally spaced in frequency, which is very interesting.  Many of these
frequencies also appear in Dolez 2005.  Of course, we also find 
numerous combination frequencies. Take a look at the web page under 
"Interesting Plots" to see the latest.  
3)G132-12 - this beginning of night target was chosen because of its 
temperature (reported as 12,800 K) and the fact that it only has one mode of 
pulsation (very low amplitude).  The idea is to gather enough cycles 
(period is about 212 s) to create a pulse shape which we can then use for 
convective light curve fitting.  Many of you might remember the figure 
from the EC14012 paper that shows our latest empirical relation.  We 
definitely need more hot stars, as G117-B15A is currently our only example.  
With the addition of WHT, Hawaii, and KPNO data, G132-12 has proven to be 
interesting.  Its pulsation mode is a multiplet with a splitting of 
around 4.1 microHz.  It may be an l=2 mode, but that is unclear. Of 
course, more data is needed:)
4)EC04207 - We have a beautiful FT of this star, thanks to contributions from 
Mt. John, SAAO, Prompt, and SOAR.  This is a large amplitude DB pulsator 
dominated by a single mode that is surprisingly stable. We are working 
towards an eventual pdot measurement.
5) EC05221 - very little is known about this fairly new DBV.  We now know
that it is the DB example of a type of white dwarf pulsator we like to call
the "soft and squishy" stars.  As we add more data to this star's light 
curve, the amplitudes in the FT continue to decrease.  This is a sign
of instability/amplitude modulation.  This star is very similar to R808
and G38-29.

Watch the Night Sky

Webcam at McDonald Observatory

 http://www.as.utexas.edu/mcdonald/webcams/monet-n-sky.jpg

Greetings from Hawaii from Judi Provencal

Thorsten Nagel at Tuebingen in Germany

Simon Jeffery at the William Herschel Telescope. The WHT is a 4 m telescope located in the Canary Islands.

New Member of the WET Team

Congratulations to Susan and Fergal --

Patrick Paul Mullally was born Thanksgiving morning, 24th November
2011 at  1:05 Pacific Time in Kaiser Permanente Hospital of Santa
Clara, California.

Weighing at 4.18 kg (over 9 lbs for you old fashioned types) and
measuring 52 cm from top to tail, it took 38 hours of labour to
convince him that exploring the outside world was not just a
suggestion from his mother.

Mother and baby are doing well, father is an emotional wreck.

SAAO, in South Africa

WET Headquarters

                                      Aiying and James at HQ, talking about reducing data!

XCOV28 Part II

Hello everyone!

We are gearing up for XCOV28 Part II.  The first part of the run has
shown us some exciting data for HS0507+0434B and
HLTau 76.  Both are very interesting targets.  HS0507 is showing signs
of multiplet structure and HL Tau 76's light curves
are looking very nonlinear.  I am looking forward to seeing the FTs of
these stars (and the southern targets) evolve as
the run goes on.

We have a list of preliminary contact times for the different
observatories, which I am enclosing.  These times are simply
approximately one hour before sunset at each observatory.  If you
would prefer a different contact time, or if I have made
a mistake in converting, please let us know.

We will be setting up a "Google Hangout", where anyone who is
observing and/or is just interested, will be able to
chat about the data and the run.  You will need a webcam for this to
work.  We will send more details when everything is
ready to go.  Also, we have a blog at
http://www.wholeearthtelescope.blogspot.com/  If you would like to
send any pictures
of your observatory, we will put them on the blog. Most of the
pictures there now are from the DAMP04 run last May.

Cheers,
Judi

XCOV28

Hello everyone,

Just a quick update on the progress of XCOV28.  I just updated the
website (www.physics.udel.edu/darc) with the latest information that I
have.  If there are any changes, please let me know.

It looks like XCOV28 will start on Nov 1 with the UH 2.2m.  The most
intense coverage will be between Nov 20 - Dec 16.  We still have a few
telescopes with upcoming deadlines, and a few that
will definitely be participating, but we do not have exact dates yet.
Right now, we have 19 telescopes.

We have spent some time considering secondary targets, and I think we
have arrived at a good mix.  The primary target is HS0507+0434B
proposed by Gerard Vauclair.  This is a multiperiodic star with a high
amplitude and a nonlinear light curve.  Its temperature of about 11500
K puts it in a currently unsampled region of space on our convection
plot.  So this is a very interesting target from both an
asteroseismology and convective light curve fitting view.

We have two additional southern targets.  EC04027 is a very large
amplitude DB pulsator that is dominated by a single mode.  Our goals
are to obtain a convective light curve fit of this star, as well as
study its stability for possibly measuring its rate of period change.
BPM31594 is a DA pulsator that looks a lot like PG1351, with a single
mode and subharmonics.  We are planning on folding this star's light
curve to obtain a convective light curve fit.

Finally, we have two additional northern targets.  HL Tau 76 is a well
known multiperiodic DA star with a nonlinear light curve.  G191-16 has
a similar light curve.  We are including these stars to examine
their potential for convective light curve fitting.  If the weather is
great everywhere, we may be able to obtain these goals with this run:)

We are also putting together our Headquarters crew.  If you are
interested in coming to HQ for part of the run, let me know.

Cheers,
Judi

Sad News

Hello everyone, A few days ago, we received the sad news that Carl Hansen passed away last week.  For those of you who never met him, Carl was a very special person.  He was one of the "founding fathers" of stellar seismology.  I remember him from my days at Texas.  He was always so enthusiastic and full of energy.  I particularly remember one time he saved us by producing an FT program that took advantage of the "chunk" nature of WET data.  Remember, this is back in the day when 386 desktop machines were the state of the art, and we had to use the UT Cray to do dfts of WET datasets.  It would take hours to so a single dft.  Carl produced an FT code that would compute a FFT of each night of observations, and then combine these chunks to produced the equivalent of a DFT, but in much less time:)  I was one graduate student who was very, very grateful!  Many of our codes from that time are named after him, such as shapecarl (which produces a pulse shape from data in "Carl's" format) and sumcarl, which sums data written in Carl's format. Carl was Don Winget's co-advisor at the University of Rochester.  I asked him to write a bit about Carl, and he produced a beautiful tribute to Carl that he would like to share with everyone..... From Don: On the 3rd of July, 2011, we lost Carl J. Hansen.  Carl was a dear friend, mentor and colleague to many of us, he influenced was and is felt across the entire field of astrophysics.  I am sure no one is fully aware of all of Carl's many contributions to the fields of physics and astronomy: they were many and varied.  Carl was a very humble man and never took the credit he deserved.  Professionally, Carl was an excellent theoretical astrophysicist with wide and varied interests.  He did pioneering work in nucleosynthesis, astro-particle physics of the production of neutrinos in stars, hydrodynamics, and stellar pulsations.  He led the way in these fields with major contributions in the areas of analytical theory and in numerical simulations.   He also was justifiably proud of his experimental work on laboratory constraints to our understanding of nuclear reactions in astrophysics, the perspective he gained from this work was an asset in his theoretical work in other areas. One of Carl's great scientific legacies is represented by the many codes he wrote from the 1970's and 1980's that are still being used today; many new codes have their roots in Carl's work.  Carl freely gave away--"with both hands,"as Ed Nather liked to remark--these codes to his students and colleagues; in this way he was one of the scientific co-founders of the concept of open source. His major scientific legacy was as a person.  His unbridled and boundless enthusiasm for life and for science quickly infected all he came into contact with.  After working, or even talking, with him, you always came away excited and energized.  This quality made him a one-man social network: everyone loved working with him so much that they encouraged others to do the same.   This made his scientific and personal influence as broad as any scientist I have every known.  You couldn't work with him without being transformed, becoming--at least a little bit--like him.  This was a great thing.  For this reason, Carl will always be present in each of our lives. Some personal recollections: Carl treated all people, always, with respect.  He was oblivious to social hierarchy, real or imagined, in any form.  He made it a point to get to know everyone he interacted with as an equal.  I will never forget when I first met him in person.  I was a new grad student at the University of Rochester and my thesis advisor there, Hugh Van Horn--having worked with Carl while on sabbatical at University of Colorado--recommended him to me as a co-advisor.  I was elated and quickly agreed.  Following tradition at the U of R, Hugh introduced Carl as "Professor Hansen."  Carl simply added, with a slight air of correction, "I'm Carl."  Hugh, taken slightly aback, said, "Are you sure?"  To which Carl responded, "Last I checked..."  I knew right away I was going to like him! I was in the final year or so of my Ph.D. work under the joint supervision of Carl and Hugh and in collaboration with Gilles Fontaine.  I was very worried by the fact that a formidable figure in stellar pulsation theory, Wojtek Dziembowski, was collaborating with another leading astrophysicist, Detlev Koester, in direct competition with us to solve the problem of the excitation of pulsations in DA white dwarf stars.  One day, I was particularly discouraged, sitting at my desk with my head in my hands.  The phone rang.  The voice on the other end said, "Beat Wojtek! Beat Wojtek! Beat Wojtek!" then the phone went dead without introduction or closing.  You can guess who's voice it was on the other end of the phone.  After his call I was buoyed and returned to working hard on our problem.  This phone call was repeated several times during the "home stretch" of this work and the project ended in success.  Carl made you feel anything was possible.  This is but one of the many ways I am personally indebted to Carl for my career in astronomy. Carl was an incredibly loyal person.  He was co-supervising my first graduate student, Steve Kawaler, with me when our talk turned to baseball--not surprising for either Steve or me.  We asked Carl how interested he was in baseball and in what team, if any.  Carl said, "Baseball died for me when the Dodgers left Brooklyn!"  No more need be said. Carl and Camille were kind enough to welcome me into their home when I visited Boulder.  They always made me feel comfortable.  Their home was filled with the bustle of chores, until the dinner conversations wound down, usually after the dishes were done.   Starting and ending each day in quiet conversation with Carl and Camille is a memory I will always treasure.  It was an oasis of beauty, peace and tranquility.

Town near the observatory in Croatia.

Aleksandr Sergeev and his cat

One More

The hard working observers at Meyer Observatory (PJMO)

Damp04 Update

  Hello everyone,

Damp04 is moving right along!  We have been dealing with clouds, fog,
thunderstorms, telescope issues, ccd problems, and even some injuries!
But the data are still coming, and our targets are looking very
interesting.

We are now getting ready to enter the second busy part of Damp04.  We
have some very interesting data so far.  GD358 continues to be very
challenging.  If you go to the website and click on "Interesting
Plots" you will see our most recent GD358 light curves and FTs.  There
is a plot that compares the GD358 FT for the first part of the run
(until ~May 12) to the newer data (May 16-19).  We had two days with
clouds and no new GD358 data.  The peak at 1735.7 microhz is mostly
unchanged (1735.783 on May 12 vs 1735.987 on May 21) but we can see
several differences.  The 954 microHz peak has increased from 2 mma to
15 mma.  The 1247 microhz peak has behaved similarly (2mm on May 12 to
15 on May 21).

EC14012-1446 is also very interesting.  This star was a 2008 XCOV27
target.  The main frequency is 1633 microhz, one of the two largest
frequencies observed in 2008.  However, its amplitude is now a
whooping 54 mma, over twice as large as observed in 2008.

Aleksandr has sent some wonderful pictures from Terskol, which I've
attached. Peak Terskol is a very beautiful place.  We also have a
story from Willie Strickland at PJMO in Texas.  I don't if everyone
remembers, but last year Willie had some surprise visitors to PJMO
(see Unwanted Guests).  The guests were fortunately more interested in
the baby birds.  This year Willie removed that tempation by placing a
styrofoam cup to keep the birds away:)

We have started a blog for this run.  If you go to the run page and
click on "WET BLOG"  it will take you there.  It is still under
construction, but please check it out:)

Cheers,
Judi

DAMP04

Hello everyone,

We've completed the first stage of Damp04.  Things are fairly quiet
right now, with only two sites observing.  Things will start to pick
up again in a few days as more telescopes come on line in the middle
of May.

We have a very nice light curve of GD358, along with some preliminary
data on WDJ1524, EC14012, and the KIC10139564.  Take a look at the
website (https://ms10.nss.udel.edu/wm/mail/fetch.html?urlid=0523e2a48046fdfab00361f80566c426b&url=http%3A%2F%2Fdarc.physics.udel.edu%2Fwet%2Fdamp04%2Fphptools%2Findex.php)
under "Interesting Plots" to see the current light curve, FT, and a
few other interesting plots.  We have filled nearly every gap at a
least once, especially at the beginning of the run, so the spectral
window is decent, although the one day aliases have been growing back
in.

One of our goals with GD358 is to resolve the k=8 and 9 multiplets,
the only two of GD358's modes that are always triplets. We have
achieved this goal, and the resulting figure is given on the website.
This figure monitors the width of the k=8 triplet, and the m=(0,1) and
m=(0,-1) splittings since 1990.  The asymmetric splitting can change,
as it did during the 1996 "event" known as the whoopsie.  This year,
both splittings are nearly symmetric.  The physical reasons are
unclear, but the k=9 and 8 modes do seem to be behaving in interesting
ways, as shown in the travelling FT figures also on the website.

We will continue monitoring GD358 as the run continues, as well as
obtaining more observations of EC14012 and WDJ1524.

Cheers,
Judi