J/MNRAS/449/1380 Optical chromospheric activity of V711 Tau (Cao+, 2015)
Chromospheric activity and rotational modulation of the RS Canum Venaticorum
binary V711 Tauri during 1998-2004.
Cao D., Gu S.
<Mon. Not. R. Astron. Soc., 449, 1380-1390 (2015)>
=2015MNRAS.449.1380C 2015MNRAS.449.1380C (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Binaries, spectroscopic ; Spectra, optical ;
Equivalent widths
Keywords: stars: activity - binaries: spectroscopic - stars: chromospheres -
stars: individual: V711 Tau - stars: late-type
Abstract:
We present long-term high-resolution spectroscopic observations of the
very active RS Canum Venaticorum-type star V711 Tau, obtained during
several observing runs from 1998 to 2004, and study its chromospheric
activity. Using the spectral subtraction technique, several optical
chromospheric activity indicators [including the He I D3, Na I D1,
D2, Hα and Ca II infrared triplet (IRT) lines] formed at different
atmospheric heights are analysed. Strong chromospheric emission supports
earlier results that indicate that V711 Tau is a very active system.
Two large optical flares were detected during our observations. The results
suggest that the main part of chromospheric emission is attributed to
the primary star of the system. The secondary also presents weak emission
but is less active. The ratios of EW8542/EW8498 indicate that
CaII IRT emission arises predominantly from plage-like regions. We have
found rotational modulation of chromospheric activity in the Hα and
CaII IRT lines, which suggests the presence of the chromospheric active
longitudes over the surface of V711 Tau. Two active longitudes separated
by about 180° were observed to dominate the activity, and the so-called
flip-flop phenomenon was seen during our observations. Moreover, the
chromospheric activity level shows a long-term variation that gradually
increases from a deep minimum near the year 2002. A close spatial
connection of photospheric spots and chromospheric active regions in both
short and long timescales was found for V711 Tau.
Description:
Spectroscopic observations of V711 Tau were performed during several
observing seasons from 1998 to 2004. The observations were carried out
with the 2.16-m telescope at the Xinglong station of the National
Astronomical Observatories, China. The Coude echelle spectrograph with
a resolving power of about 37000 and a 1024x1024-pixel Tektronix CCD
detector were used (Zhao & Li 2001ChJAA...1..555Z 2001ChJAA...1..555Z). The reciprocal
dispersions are 0.082 Å/pixel for the NaI D1, D2, HeI D3
spectral region, 0.091 Å/pixel for the Hα spectral region,
0.118 Å/pixel for the CaII λλ8498, 8542 spectral
region, and 0.120 Å/pixel for the CaII λ8662 spectral region.
Correspondingly, the spectral resolution determined as the full width
at half-maximum of the arc comparison lines is 0.152, 0.167, 0.211 and
0.216 Å, respectively. In total, 67 spectra of V711 Tau were obtained.
Objects:
-------------------------------------------------
RA (ICRS) DE Designation(s)
-------------------------------------------------
03 36 47.29 +00 35 15.9 V711 Tau = HD 22468
-------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 33 67 Observing log of V711 Tau
table2.dat 73 67 Measurements for excess emission of the CaII
infrared triplet (IRT) and Hα lines in
the subtracted spectra
--------------------------------------------------------------------------------
See also:
J/A+A/469/309 : Chromospheric activity in late-type stars (Cincunegui+, 2007)
J/A+A/521/A36 : BV differential photometry of V711 Tau (Muneer+, 2010)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 "date" Date Date of observation
13- 21 F9.4 d HJD [885.964/3339.3] Heliocentric Julian Date
(HJD-2450000)
23- 28 F6.4 --- Phase [0.0818/0.991] Orbital phase
30- 33 I4 s ExpTime [600/3600] Exposure time
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Year [1998/2004] Year of observation
6- 12 A7 --- Month Month(s) of observation
14- 19 F6.4 --- Phase [0.0818/0.991] Orbital phase
21- 25 F5.3 0.1nm EW(8498) [0.609/0.868]? Equivalent width for the
CaII IRT λ8498 (Å)
27- 31 F5.3 0.1nm e_EW(8498) [0.001/0.031]? Uncertainty in EW(8498)
(Å)
33- 37 F5.3 0.1nm EW(8542) [0.86/1.237] Equivalent width for the
CaII IRT λ8542 (Å)
39- 43 F5.3 0.1nm e_EW(8542) [0.001/0.035] Uncertainty in EW(8542)
(Å)
45- 49 F5.3 0.1nm EW(8662) [0.768/1.093] Equivalent width for the
CaII IRT λ8662 (Å)
51- 55 F5.3 0.1nm e_EW(8662) [0.001/0.039] Uncertainty in EW(8662)
(Å)
57- 61 F5.3 0.1nm EW(Ha) [1.866/3.989] Hα equivalent width
(Å)
63- 67 F5.3 0.1nm e_EW(Ha) [0.003/0.035] Uncertainty in EW(Ha) (Å)
69- 73 F5.3 0.1nm EW(8542/8498) [1.244/1.607]? Ratio of excess emission,
EW8542/EW8498
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 08-Nov-2019