AAVSO Alert Notice 473

T Tauri stars observing campaign
November 6, 2012

Darryl Sergison (University of Exeter) has requested AAVSO
assistance with a campaign he is organizing on six T Tauri stars.
He writes: "In Autumn 2013 I [and my PhD supervisor Tim Naylor of
Exeter University are] undertaking a new study into the nature of
pre-main-sequence low mass stars, using time series optical
spectroscopy and UV-Visual-IR photometry...to build a clearer
picture of the environment around young solar-type stars and
characterise their various disc, accretion, and outflow structures.

"This study offers a great opportunity for professional-amateur
collaboration as the objects (with V magnitudes of 10 - 13) are
well within the reach of photometry by small telescopes. Amateur
observations are uniquely useful to us in the study of chaotically
variable young stars as they offer crucial datapoints in the
lightcurve between observations made by professional telescopes.

"We would be very keen to recruit(!) AAVSO observers who are
interested in being part of this study and able to contribute
visual or (V and Rc band) filtered CCD photometry. All contributing
observers will be acknowledged in the published papers, significant
contributors may also be co-authors. I do have one spare 1.25"
V band filter that I could lend to any interested observer who may
wish to borrow it for the duration of this programme. [If you are
interested in borrowing it please email eowaagen@aavso.org].

***"In preparation for the main data collection next autumn, we would
like to start monitoring targets immediately. The first 3 targets
that we will be studying are RY Tau, DN Tau, and DR Tau [the other
3 targets will be announced later]... ***

"As far as observations go, almost anything is useful. We are
hoping to investigate periodicity for a range of phenomena on
timescales of months to hours, so visual estimates ranging from
monthly to twice in a night would be great.

"Filtered CCD measurements in any of B, V, Ic, or Rc would be
great, again low cadence is useful, higher cadence (hourly or
long time series) is better! Unfiltered is probably of less use
to us due to the difficulties with system response and changing

"Spectroscopy would be very welcome, particularly around H-alpha
(6563A) if the resolution is greater than a few thousand.
Alternatively, low resolution right across the optical would be
great (for example with a diffraction grating in the converging
beam), particularly if a nearby main sequence star of similar
spectral type can be captured at a similar time and air-mass so
that we can characterise the system and atmosphere response at
the time of the observation."

Coordinates (2000) and Range and B-V:
RY Tau  RA 04 21 57.41 Dec +28 26 35.6   9.3-13.0 p   1.0
DN Tau  RA 04 35 27.38 Dec +24 14 58.9  11.5-14.7 p   1.4
DR Tau  RA 04 47 06.22 Dec +16 58 42.8  10.5-16 B     1.2

Charts for these stars may be created using the AAVSO Variable
Star Plotter (www.aavso.org/vsp). Photometrists should use the
photometry table provided in VSP for each star.

Please report all observations to the AAVSO International Database
using the names RY TAU, DN TAU, and DR TAU, respectively.

This campaign is being followed on the AAVSO Observing Campaigns
page (www.aavso.org/observing-campaigns).

This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.


Première observation hier soir, soirée trés venteuse, le signal avait du mal à rentrer dans la fibre. Je pense qu'on peut faire deux fois mieux et que ça reste à la portée d'un Lhires2400.




autre observation:





Spectres disponibles:



Observation 2013

AAVSO Alert notice 494








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