Sam Wormley wrote:
INBOX ASTRONOMY: NEWS ALERT wrote:
FOR RELEASE: 1:00 pm (EDT) August 8, 2006

Ray Villard
Space Telescope Science Institute, Baltimore, Md.
(Phone: 410-338-4514; E-mail: )

David Bennett
University of Notre Dame, Notre Dame, Ind.
(Phone: 574-631-8298; E-mail: or
)

PRESS RELEASE NO.: STScI-PR06-38

HUBBLE IDENTIFIES STELLAR COMPANION TO DISTANT PLANET


Here is an actual preprint--free of the science writer's take.


The First DIRECT Distance Determination to a Detached Eclipsing Binary
in M33
http://xxx.lanl.gov/abs/astro-ph/0606279

Authors: A. Z. Bonanos, K. Z. Stanek, R. P. Kudritzki, L.M. Macri, D.
D. Sasselov,
J. Kaluzny, P. B. Stetson, D. Bersier, F. Bresolin, T. Matheson,
B.J. Mochejska,
N. Przybilla, A.H. Szentgyorgyi, J. Tonry, G. Torres

Comments: 36 pages, 12 figures, accepted for publication in ApJ

We present the first direct distance determination to a detached
eclipsing binary in M33, which was found by the DIRECT Project.
Located in the OB 66 association at coordinates (alpha, delta)=
(01:33:46.17,+30:44:39.9) for J2000.0, it was one of the most
suitable detached eclipsing binaries found by DIRECT for distance
determination, given its apparent magnitude and orbital period.

We obtained follow-up BV time series photometry, JHKs photometry
and optical spectroscopy from which we determined the parameters
of the system. It contains two O7 main sequence stars with masses
of 33.4+/-3.5 Mo and 30.0+/-3.3 Mo and radii of 12.3+/-0.4 Ro and
8.8+/-0.3 Ro, respectively. We derive temperatures of 37000+/-1500 K
and 35600+/-1500 K. Using BVRJHKs photometry for the flux calibration,
we obtain a distance modulus of 24.92+/-0.12 mag (964+/-54 kpc),
which is ~0.3 mag longer than the Key Project distance to M33.
We discuss the implications of our result and the importance of
establishing M33 as an independent rung on the cosmological distance
ladder.

http://xxx.lanl.gov/pdf/astro-ph/0606279




News of the Universe
An Older but Larger Universe?
http://www.astro.ucla.edu/~wright/cosmolog.htm#News
NOTE: URL includes links

Ohio State astronomers have measured a new precise distance to the
nearby galaxy M33 based on a spectroscopic eclipsing binary. Their
value is 15% larger than the old Cepheid based distance. By itself this
says nothing about the Hubble constant because M33 is so close to the
Milky Way that its radial velocity is dominated by random motions, not
the expansion of the Universe. But it could indicate that Cepheid
distances are incorrect by 15%.

If so, the Hubble constant would be smaller: about 62 instead of 72
km/sec/Mpc. But the claim in the OSU press release that "the universe
could be [...] 15 percent older" is incorrect. If the Hubble constant
is lower, then CMB anisotropy data require that OmegaM, the ratio of
the matter density to the critical density, be higher, so the vacuum
energy is lower, and the change in the age of the universe is
considerably smaller, as shown in graph at right [click on the graph to
enlarge] which shows the age vs. Ho for CMB consistent models as the
solid curve, and the 1/Ho behavior assumed by the OSU press release as
the dashed curve. So the Universe would not be 15% older but perhaps 7%
older.

The claim that the Universe would be 15% larger is partially incorrect.
Even though relatively nearby galaxies would be 15% further away the
actual size of the Universe would go from infinite (open) to finite
(closed) but very big, which is a smaller Universe. The distance to
distant quasars at redshift z=6 would increase by only 4%, and the
distance to the last scattering surface changes less than 0.5% because
this is what is fixed by the CMB.

CNN quoting space.com and John Johnson of the LA Times accepted the
press release's claims of a 15% older and larger Universe uncritically.
The real news is that a new method for precision distance measurements
has achieved its first result. It will be averaged in with other
methods used to calibrate the Cepheid period-luminosity relation and
lead to a few percent decrease in the Hubble constant.