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J/A+A/520/A79   Nearby FGK stars chromospheric activity (Martinez-Arnaiz+, 2010)

Chromospheric activity and rotation of FGK stars in the solar vicinity. An estimation of the radial velocity jitter. Martinez-Arnaiz R., Maldonado J., Montes D., Eiroa C., Montesinos B. <Astron. Astrophys. 520, A79 (2010)> =2010A&A...520A..79M
ADC_Keywords: Stars, late-type ; Radial velocities ; Rotational velocities ; Equivalent widths Keywords: solar neighbourhood - stars: late-type - stars: activity - stars: chromospheres - stars: rotation - stars: planetary systems Abstract: Chromospheric activity produces both photometric and spectroscopic variations that can be mistaken as planets. Large spots crossing the stellar disc can produce planet-like periodic variations in the light curve of a star. Moreover, spots clearly affect the spectral line profiles. Such perturbations will in turn affect the line centroids creating a radial velocity jitter that might "contaminate" the variations induced by a planet. Precise chromospheric activity measurements are needed to estimate the activity-induced noise that should be expected for a given star. The purpose of this paper is to obtain precise chromospheric activity measurements and projected rotational velocities for nearby (d<25pc) cool (spectral types F to K) stars, in order to estimate the activity-related jitter that should be expected for them. As a complementary objective, in this paper we aim to obtain relationships between fluxes in different activity indicator lines, which will permit a transformation of traditional activity indicators, i.e, CaII H & K lines, to other which hold noteworthy advantages. We used high resolution (∼50000) echelle optical spectra. Standard data reduction was performed using the IRAF echelle package. To reveal the chromospheric emission of the stars in the sample we used the spectral subtraction technique. We measured equivalent widths of the chromospheric emission lines in the subtracted spectrum and transformed them into fluxes by applying empirical equivalent width-flux relationships. Rotational velocities were determined using the cross-correlation technique. To infer activity-related radial velocity (RV) jitter we used empirical relationships between this and the R'HK index. We have measured chromospheric activity, as given by different indicators throughout the optical spectra, and projected rotational velocities for 371 nearby cool stars. We have built empirical relationships among the most important chromospheric emission lines. Finally, we have used the measured chromospheric activity to estimate the expected RV jitter for the active stars in the sample. Description: Rotation, excess chromospheric emission (equivalent widths and fluxes) and estimated radial velocity jitter for 371 F, G and K stars in the solar vicinity (d<25pc). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tablea1.dat 88 423 Stellar parameters of the stars tablea2.dat 98 182 Excess emission (equivalent widths) tablea3.dat 92 182 Excess emission (Flux) & logR'HK tablea4.dat 56 181 Estimated radial velocity jitter
See also: J/A+A/331/581 : Rotation and activity in field M dwarfs (Delfosse+ 1998) J/A+A/469/309 : Chromospheric activity in late-type stars (Cincunegui+, 2007) Byte-by-byte Description of file: tablea1.dat
Bytes Format Units Label Explanations
1- 6 I6 --- HIP HIP number of the star 8- 9 A2 --- n_HIP [+* ] Notes (1) 11- 18 A8 --- Spect Spectrograph used 20- 29 F10.4 d MJD Modified Julian Date 31- 32 I2 h RAh Right ascension (J2000.0) 34- 35 I2 min RAm Right ascension (J2000.0) 37- 41 F5.2 s RAs Right ascension (J2000.0) 43 A1 --- DE- Declination sign (J2000) 44- 45 I2 deg DEd Declination (J2000) 47- 48 I2 arcmin DEm Declination (J2000) 50- 53 F4.1 arcsec DEs Declination (J2000) 55- 59 F5.3 mag B-V B-V colour index 61- 69 A9 --- SpType MK spectral type 71- 72 A2 --- l_vsini [≥ ] Limit flag on vsini 73- 77 F5.2 km/s vsini ?=- Projected rotational velocities 79- 88 A10 --- Activ Activity of the star
Note (1): Notes as follows: + = stars with known exoplanets * = stars with chromospheric variation during our observations
Byte-by-byte Description of file: tablea2.dat
Bytes Format Units Label Explanations
1- 6 I6 --- HIP HIP number of the star 8- 15 A8 --- Spect Spectrograph used 17- 26 F10.4 d MJD Modified Julian Date of observation 28- 32 F5.3 0.1nm W(K) ?=- CaII K excess emission equivalent width 34- 38 F5.3 0.1nm e_W(K) ? Error in W(K) 40- 44 F5.3 0.1nm W(H) ?=- CaII H excess emission equivalent width 46- 50 F5.3 0.1nm e_W(H) ? Error in W(H) 52- 56 F5.3 0.1nm W(Ha) ?=- Hα excess emission equivalent width 58- 62 F5.3 0.1nm e_W(Ha) ? Error in W(Hα) 64- 68 F5.3 0.1nm W(IRT1) ?=- CaII IRT1 excess emission equivalent width 70- 74 F5.3 0.1nm e_W(IRT1) ? Error in W(IRT1) 76- 80 F5.3 0.1nm W(IRT2) ?=- CaII IRT2 excess emission equivalent width 82- 86 F5.3 0.1nm e_W(IRT2) ? Error in W(IRT2) 88- 92 F5.3 0.1nm W(IRT3) ?=- CaII IRT3 excess emission equivalent width 94- 98 F5.3 0.1nm e_W(IRT3) ? Error in W(IRT3)
Byte-by-byte Description of file: tablea3.dat
Bytes Format Units Label Explanations
1- 6 I6 --- HIP HIP number of the star 8- 15 A8 --- Spect Spectrograph used 17- 26 F10.4 d MJD Modified Julian Date of observation 28- 32 F5.3 [mW/m2] F(K) ?=- CaII K excess emission flux (log) 33- 37 F5.3 [mW/m2] e_F(K) ? Error logF(K) 38- 42 F5.3 [mW/m2] F(H) ?=- CaII H excess emission flux (log) 43- 47 F5.3 [mW/m2] e_F(H) ? Error logF(H) 48- 52 F5.3 [mW/m2] F(Ha) ?=- Hα excess emission flux (log) 53- 57 F5.3 [mW/m2] e_F(Ha) ? Error logF(Hα) 58- 62 F5.3 [mW/m2] F(IRT1) ?=- CaII IRT1 excess emission flux (log) 63- 67 F5.3 [mW/m2] e_F(IRT1) ? Error logF(IRT1) 68- 72 F5.3 [mW/m2] F(IRT2) ?=- CaII IRT2 excess emission flux (log) 73- 77 F5.3 [mW/m2] e_F(IRT2) ? Error logF(IRT2) 78- 82 F5.3 [mW/m2] F(IRT3) ?=- CaII IRT3 excess emission flux (log) 83- 87 F5.3 [mW/m2] e_F(IRT3) ? Error logF(IRT3) 88- 92 F5.2 --- log(R'HK) ?=- Activity index derived from the CaII H+K lines
Byte-by-byte Description of file: tablea4.dat
Bytes Format Units Label Explanations
1- 6 I6 --- HIP HIP number of the star 8 A1 --- f_HIP [d] d for stars with log(R'HK)←4.9 10- 17 A8 --- Spect Spectrograph used 19- 28 F10.4 d MJD Modified Julian Date 30- 35 A6 --- SpType MK spectral type 39- 43 F5.2 --- log(R'HK) Activity index derived from CaII H+K lines 45- 46 I2 m/s sigRV1.l Lower value of estimated RV jitter from Saar et al., 1998ApJ...498L.153S 47 A1 --- --- [-] 48- 50 I3 m/s sigRV1.u Upper value of estimated RV jitter from Saar et al., 1998ApJ...498L.153S 52- 53 I2 m/s sigRV2.l Lower value of estimated RV jitter from Santos et al., 2000A&A...361..265S 54 A1 --- --- [-] 55- 56 I2 m/s sigRV2.u Upper value of estimated RV jitter from Santos et al., 2000A&A...361..265S
Acknowledgements: Raquel Martinez-Arnaiz, rma(at)astrax.fis.ucm.es
(End) Patricia Vannier [CDS] 04-Feb-2010
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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