Publications
as
co-author
Observations
of
the first confirmed superoutburst of SDSS J080434.20+510349.2 in 2006
March
By J.Shears, G.
Klingenberg and P. de Ponthière
http://arxiv.org/abs/0705.4616
Journal of British Astronomical Association (May 2007)
Abstract :
During 2006
March the first confirmed superoutburst of the dwarf nova SDSS
J080434.20+510349.2 was observed using unfiltered CCD photometry.
Time-series photometry revealed superhumps with a period of 0.0597 +/-
0.0011 d and an amplitude of 0.2 magnitude, thereby independently
establishing its UGSU classification. Following the decline from a peak
magnitude of 13.1, at least two rebrightening events were observed.
Evidence is presented which is consistent with the star being a member
of the UGWZ sub-class.
Discovery
of Very
Bright, Nearby Gravitational Microlensing Event
By J. Patterson
and others
http://arxiv.org/abs/astro-ph/0703125
March 2007
Abstract :
We report the
serendipitous detection of a very bright, very nearby microlensing
event. In late October 2006, an otherwise unremarkable A0 star at a
distance ~1 kpc (GSC 3656-1328) brightened achromatically by a factor
of nearly 40 over the span of several days and then decayed in an
apparently symmetrical way. We present a light curve of the event based
on optical photometry from the Center for Backyard Astrophysics and the
All Sky Automatic Survey, as well as near-infrared photometry from the
Peters Automated Infrared Imaging Telescope. This light curve is
well-fit by a generic microlensing model. We also report optical
spectra, and Swift X-ray and UV observations that are consistent with
the microlensing interpretation. We discuss and reject alternative
explanations for this variability. The lens star is probably a low-mass
star or brown dwarf, with a relatively high proper motion of >20
mas/yr, and may be visible using precise optical/infrared imaging taken
several years from now. We demonstrate that a modest, all-sky survey
telescope could detect ~10 such events per year, which would enable
searches for very low-mass planetary companions to relatively nearby
stars.
The
detection of
the WZ Sge-type nature of the dwarf novae ASAS 023322-1047.0 and ASAS
102522-1542.4 by the Center for Backyard Astrophysics.
By T. Vanmunster
and others
http://www.socastrosci.org/2006%20papers/Vanmunster_WZSgeDwarfNovae.pdf
Proceedings for the 25th Annual Conference of the Society for
Astronomical Siemces (May 2006)
Abstract :
We present the
results of a detailed analysis of 13,116 time-series CCD photometry
observations of the cataclysmic variable stars ASAS 023322-1047.0 and
ASAS 102522-1542.4, collected during 175.1 hours over 23 nights early
2006, by 9 observers. We report a/o the detection of outburst orbital
humps and common superhumps, establishing the variables as genuine new
members of the rare class of WZ Sge-type dwarf novae. Our observations
furthermore provide an excellent basis to illustrate how the pro-am
partnership of the Center for Backyard Astrophysics is implemented in
practice. © 2006 Society for Astronomical Science.
Other
contributions
Late-Type
Near-Contact Eclipsing Binary [HH97] FS Aur-79
By S.J. Austin, J.W. Robertson and others
http://www.arxiv.org/PS_cache/astro-ph/pdf/0702/0702171.pdf
Abstract:
The secondary photometric standard star #79 for the FS Aur field
(Henden & Honeycutt 1997) designated as [HH97] FS Aur-79 (GSC 1874
399) is a short period (0.2508 days) eclipsing binary whose light curve
is a combination of the beta Lyr and BY Dra type variables. High
signal-to-noise multi-color photometry were obtained using the USNO 1-m
telescope. These light curves show asymmetry at quadrature phases
(O'Connell effect), which can be modeled with the presence of star
spots. A low resolution spectrum obtained with the 3.5-m WIYN telescope
at orbital phase 0.76 is consistent with a spectral type of dK7e and
dM3e. A radial velocity curve for the primary star was constructed
using twenty-four high resolution spectra from the 9.2 m HET. Spectra
show H-alpha and H-beta in emission confirming chromospheric activity
and possibly the presence of circumstellar material. Binary star models
that simultaneously fit the U, B, V, R and RV curves are those with a
primary star of mass 0.59+-0.02 Msun, temperature 4100+-25 K, mean
radius of 0.67 Rsun, just filling its Roche lobe and a secondary star
of mass 0.31+-0.09 Msun, temperature 3425+-25 K, mean radius of 0.48
Rsun, just within its Roche lobe. An inclination angle of 83+-2 degrees
with a center of mass separation of 1.62 Rsun is also derived. Star
spots, expected for a rotation period of less than a day, had to be
included in the modeling to fit the O'Connell effect.