Sziasztok!
Az orosz MASTER csapat talalt egy valoszinuleg RCB tipusu valtozot az RZ
LMi kozeleben. A csillag 10-14,3V között változik.
A MASTER OT J095310.04+335352.8 közelében található az NGC 3021,
valamint az NGC 3003 galaxis is.
Hamarosan készítünk hozzá összehasonlítókat is.
Jó észlelést!
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ATEL #4784 ATEL #4784
Title: Optical "anti-transient" detected by MASTER
Author: D. Denisenko et. al.
MASTER OT J095310.04+335352.8 - fading of TYC 2505-672-1
We have started the search for the disappearing stars (optical
"anti-transients", OATs) in the MASTER database. The first result is
the detection of a deep (~3.5 magnitudes) fading of the bright star
TYC 2505-672-1 whose variability was previously unknown. This star has
the coordinates 09 53 10.00 +33 53 52.7 and magnitudes V=10.71,
B=12.51 in Tycho2 catalogue and J=7.61, H=6.78, K=6.57 in 2MASS. It
was bright (unfiltered magnitude about 10.5) in 2010 and January-April
2011, but was found fading from R=13.0 to R=14.1 in November 2011 -
March 2012 after the seasonal gap in observations due to the
conjunction with the Sun. Since then it resides at a low state for
almost a year.
The light curve from MASTER-Amur observations is posted at
http://master.sai.msu.ru/static/OT/TYC2505-672-1-MASTER-Amur-LC.gif
and selected magnitudes are listed in the table below.
2011-02-03 15:15:47 10.34W MASTER-Amur
2011-03-14 10:43:18 10.03V MASTER-Amur
2011-04-07 12:30:22 10.44W MASTER-Amur
--- seasonal gap due to solar conjunction ---
2011-11-03 23:44:28 12.62W MASTER-Kislovodsk
2011-11-04 00:17:08 12.64W MASTER-Kislovodsk
2011-11-09 17:42:27 12.99R MASTER-Amur
2011-11-20 16:58:19 13.10R MASTER-Amur
2011-11-29 16:47:27 13.27R MASTER-Amur
2011-12-09 16:14:25 13.44R MASTER-Amur
2012-01-08 13:37:51 13.85R MASTER-Amur
2012-03-01 12:50:18 14.06R MASTER-Amur
2012-03-17 14:40:17 14.31V MASTER-Amur
2012-04-02 18:09:36 13.81W MASTER-Amur
--- seasonal gap due to solar conjunction ---
2012-09-29 20:02:30 13.98W MASTER-Amur
2012-10-25 19:23:53 14.03W MASTER-Amur
2012-12-19 15:46:57 14.01W MASTER-Amur
2013-01-07 16:46:19 13.77W MASTER-Amur
2013-02-01 16:51:19 13.82W MASTER-Amur
The spectral class of TYC 2505-672-1 is reported as M2III in Pickles
et al., 2010 with the estimated distance 1179 pc. Combined with the
proper motion (3.5, -7.4) mas/yr from UCAC4 catalogue (Zacharias et
al., 2012) this corresponds to the tangential velocity 46 km/s which
is reasonable. Galactic coordinates are (191.7, +51.3).
In general, the object´s behavior is similar to that of R CrB
variables (red supergiants forming clouds of carbon at irregular
intervals of time). However, the typical dimming phase of R CrB stars
is lasting from 1 week to 1 month while TYC 2505-672-1 took more than
3 months to fade from 10m to 14m. The star was nearly constant in
1999-2000 during the observations by NSVS (ROTSE-I) project, see
href="http://skydot.lanl.gov/nsvs/star.php?num=7507001&mask=32004">light
curve of NSVS 7507001. No previous fadings were detected on 9
Palomar plates taken from 1955 to 1996 and on 31 Palomar/NEAT images
taken during 9 different nights in 2001-2003. The object was not
detected in 1RXS and IRAS bright source catalogs.
We encourage the spectroscopic and photometric observations of TYC
2505-672-1. We also note that the new variable is located 21.5´ SE of
the cataclysmic variable RZ LMi (of ER UMa type) which is extensively
monitored by CV researchers. Observers are requested to check their
images of RZ LMi obtained in April-June 2011 and especially in
September-October 2011 to localize the beginning of fading episode.
Archival searches for the historical fadings are also requested.
MASTER-Amur discovery and reference images are posted at
http://master.sai.msu.ru/static/OT/J095310+335353-MASTER.jpg
List of
optical transients discovered by MASTER
Global MASTER Net: http://observ.pereplet.ru
----- End forwarded message -----
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Fidusz (FIDRICH Robert)
drotlevel:fidusz@zpok.hu
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