Sziasztok!

Egy érdekes cikk az Arxivról: A VERA-val megmérték az RX Boo
parallaxisát (egy távoli kvazár segítségével), és a távolságára 136
+10/-9 parszek jött ki.

"VLBI Astrometry of the Semiregular Variable RX Bootis"
http://arxiv.org/abs/1201.3721

"We present distance measurement of the semiregular variable RX Bootis
(RX Boo) with its annual parallax. Using the unique dual-beam system
of the VLBI Exploration of Radio Astrometry (VERA) telescope, we
conducted astrometric observations of a water maser spot accompanying
RX Boo referred to the quasar J1419+2706 separated by 1.69 degrees
from RX Boo. We have measured the annual parallax of RX Boo to be 7.31
+/- 0.50 mas, corresponding to a distance of 136 +10/-9 pc, from the
one-year monitoring observation data of one maser spot at VLSR = 3.2
km/s. The distance itself is consistent with the one obtained with
Hipparcos. The distance uncertainty is reduced by a factor of two,
allowing us to determine the stellar properties more accurately. Using
our distance, we discuss the location of RX Boo in various sequences
of Period-Luminosity (PL) relations. We found RX Boo is located in the
Mira sequence of PL relation. In addition, we calculated the radius of
photosphere and the mass limitation of RX Boo and discussed its
evolutionary status."

--
Fidusz (FIDRICH Robert)
drotlevel:fidusz@zpok.hu
#jabber/gtalk: fidusz@jabber.hu
#skype: fidusz