Nanu!

Az AAVSO-n keresztül a CfA egyik kutatója azt kéri, hogy észleljük az AB
Aur-t és az SU Aur-t a következő napokban, ugyanis az XMM-Newton röntgen
műhold is mégéreset végez e két T Tauri típusú változóról.

További info az AB Aurigaeről:

http://lmv.hu/AB_Aur

* * *

AAVSO Alert Notice 452

Simultaneous observations of SU Aur and AB Aur requested for XMM-Newton
February 8, 2012

Dr. Hans Moritz Guenther, Harvard-Smithsonian Center for Astrophysics,
has requested bracketing and simultaneous observations in support
of XMM-Newton x-ray observations of the classical T Tauri
star SU Aur and the close-by Herbig Ae star AB Aur scheduled for
February 15 - 17, 2012. The targets are too bright to use the XMM
optical monitor for simultaneous monitoring, so your observing
assistance is essential for correlation of the x-ray data.

Dr. Guenther writes, "The scientific goal of the observation is to
study the rise and decay of flares in classical T Tauri stars at
a relatively high time resolution (less than minutes). Because T
Tauri stars are surrounded by an accretion disk and actively accrete
matter from the star, there is reason to believe that flares on T
Tauri stars behave differently compared to flares on older stars
like our sun."

At visual magnitude ~9.5 and ~7.0, respectively, SU Aur and AB Aur
are bright. Thus, this campaign is best suited to observers with
smaller telescopes, as large instruments will saturate very quickly.
AB Aur is located about 3 arcmin from SU Aur, and there is a
magnitude 7.6 comparison nearby that is suitable for both stars.

The XMM-observations are scheduled for UT 20:31:13 2012 February 15 -
01:27:53 February 17. Optical observations starting a few hours before
and lasting a few hours longer would be ideal, but the main focus is
the time of the XMM-Newton observation. SU Aur flares often and Dr.
Guenther expects it will exhibit optical brightening.

Photometry should be carried out with exposure times of 1 minute
or less (and timing of the telescope clock accurate to the same
level). V filter is preferred but any filter is acceptable.
Unfiltered observations are not recommended as both stars are red.
It would be helpful if the filter and zero point were calibrated,
but since Dr. Guenther is most concerned about relative changes,
it is not required.

Nightly observations are also requested from now through February
24 to provide a good context for the simultaneous and bracketing
observations.

Coordinates (2000.0):
SU Aur R.A. 04 55 59.38  Dec. +30 34 01.5
AB Aur R.A. 04 55 45.84  Dec. +30 33 04.3

Charts may be created using VSP (http://www.aavso.org/vsp).

Please report observations to the AAVSO International Database
using the names SU AUR and AB AUR.

Your observations are crucial to the success of this campaign!
Many thanks!

----- End forwarded message -----

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