J/A+A/654/A168ivo://CDS.VizieR/J/A+A/654/A168doi:10.26093/cds/vizier.36540168CDSLiebing F.Jeffers S.V.Reiners A.Zechmeister M.2022-09-21T08:42:04Z2021-10-26T08:04:54ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frdwarf-starsspectroscopyradial-velocityThe detection of earth-mass exoplanets in the habitable zone around solar-mass stars using the radial velocity technique requires extremely high- precision of the order of 10cm/s. This puts the required noise floor below the intrinsic variability of even relatively inactive stars, like the Sun. One such variable is convective blueshift varying temporally, spatially and between spectral lines. We develop a novel approach to measure convective blueshift and determine the strength of convective blueshift for 810 stars observed by the HARPS spectrograph, spanning spectral types from late-F, G, K to early-M. We derive a model to infer blueshift velocity for lines of any depth in later-type stars of any effective temperature. Using a custom list of spectral lines, covering a wide range of absorption depths, we create a model for the line-core shift as a function of line depth, commonly known as the third signature of granulation. For this we utilize an extremely high-resolution solar spectrum (R~1.000.000) to empirically account for the non-linear nature of the third signature. The solar third signature is then scaled to all 810 stars. Through this we obtain a measure of the convective blueshift relative to the Sun as a function of stellar effective temperature. We confirm the general correlation of increasing convective blueshift with effective temperature and establish a tight, cubic relation between the two that strongly increases for stars above ~5800K. For stars between ~4100K and ~4700K we show for the first time a plateau in convective shift and a possible onset of a plateau for stars above 6000K. Stars below ~4000K show neither blue or red shift. We provide a table listing expected blueshift velocities for each spectral subtype in the data set to quickly access the intrinsic noise floor through convective blueshift for the RV technique.2021A&A...654A.168Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/654/A168CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/636/A74 : HARPS radial velocity database (Trifonov+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/654/A168https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/654/A168http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/654/A168https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/654/A168https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/654/A168http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/654/A168GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/654/A168/tablee2 (Stellar parameters and results)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/654/A168/tablee2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/654/A168/tablee2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/654/A168/tablee2?GETtext/xml+votable180.050000true217.4289381-62.67949190.0055555555555555566/60 137 222 413 461 472 4128 4206 4313 4366 4376 4665 4672 5009 8237 8244 8286 8614 8733 8792 12340-12341 12424 12644 12890 12899 12983 13440 16391 16393 16502 16518 16528 16533 16543 16603 16627 16639 16652 16750 16853 16986 16993 16995 17017 17035 17047 17171 17218 17253 17266 17288 17301 17314 17341 17374 17419 17425 17435 17447 17453 17507 17529 17540-17541 17552 17572 17587 17607 17641 17714 17730-17731 17768 17804 17870 17944 17954 17993 18115 18132 18139 18147 18209 18373 18496 18548 18553 18614-18615 18637 18641 18711 18747 18785 18792 18802 18838 18943 19003 19072 19108 19217 19466 19491 19559 20072 20100 20145 20515 20557 20582 20586 20593 20633 20640 20676 20739 20746 20873 20896 21114 21117 21121 21177 21213 21270 21326 21412 21477 21484 21516 21600 21691 21748 21779 21809 21838 21906 21912 21953 22036 22040 22065 22078 22159 22222 22252 22289 22590 22608 22613 22619 22626 22654 22708 22746 22760 22773 22787 22807 22813 22818 22837 23061 23094 23096 23123 23177 23238 23342 23429 23503 23564 23583 23661 23731 23774 23780 23872-23873 24205 24209 24597 24687 24713 24729 24769 24816 24831 24876 24924 24990 25078 25102 25225 25233 25258 25267 25276 25279 25484 25512 25567 25584 25604 25622 25624 25795 25820 25854 25862 25880 25889 25904 25906 25939 25989 26160 26183 26242 26401 26468 26496 26560 26583 26636 26652 26679 26768 26772 26796 26828 26888 26901 26906 26975 27018 27088 27164 27201 27254-27255 27462 27484 27741 27810 28341 28703 28719 28737 28763 28779 28874 28887 28891 28894 28955 28961 28987 29043 29045 29047 29170 29196 29213 29289 29349 29352 29422 29458 29513 29541 29675 29684 29730 29833 29838 29842 29900 29961 30013 30015 30123 30257 30278 30321 30343 30378 30526 30576 30707 30720 30789 30848 30862 30878 30894 30919 30929 30943 30951 30965 31011 31014-31015 31029 31101 31130 31393 31433 31494 31503 31630 31821 31945 32318 32335 32848 32912 32930 32937 32986 33042 33063 33082 33091 33179 33210 33214 33219 33243 33252 33357 33418 33430 33442 33456 33510 33552 33555 33594 33598 33608 33630 33649 33662 33693 33705 33717 33813 33850 33873 33974 34073 34172 34245 34306 34336 34350 34408 34425 34442 34481 34497 34515-34516 34530 34577 34586 34612 34638 34673-34674 34793 34817 34864 34947 34953 34983 35064 35079 35121 35146 35228 35230 35291 35324-35325 35339 35351 35388 35392 35415 35440 35442 35452 35468 35501 35590 35615 35668 35691 35733 35776 35784 35786 35790 35811 35831 35839-35840 35896 35928 35954 35968-35969 36008 36015 36019 36142 36288 36365 36412 36418 36453 36483 36517 36590 36635 36664 36697 36800 36813 36816 36899 36952 36954 37018 37047 37074 37208 37222 37357 37379 37418-37419 37422 37449 37482 37515 37565 37595 37616 37660 37679 37797 37807-37808 37831 37944 37954-37955 38099 38127 38162 38219 38229 38238 38279 38288 38311 38324 38414 38434 38443 38452 38461 38480 38521 38545 38562 38605 38698 38728 38738 38742 38757 38765 38788 38807 38836 38856-38857 38932 38936 38955 38971 38975 38998 39030 39034 39200-39201 39213 39219 39257 39282-39283 39364 39377 39422 39433 39441 39463 39500 39516 39570 39576 39623 39676 39691 39693 39709 39722 39767 39801 39854 39915 39954 40007 40078 40080 40101 40105 40143 40183 40302 40317 40442 40453 40514 40661-40662 40686-40687 40692 40722 40741 40802 40830 40862 40892 40921 40932 40938 40970 40985 41058 41094 41143 41167 41204 41252 41272 41455 41460 41463 41515 41521 41590-41591 41607 41611-41612 41660 41687 41723-41724 41752 41861 41912 41935 41941 41954 41969 42022 42044 42146 42157 42171 42197 42205 42212 42216 42224 42228 42248 42290 42326 42360 42386 42429 42448 42460 42463 42485 42501 42519 42570 42595 42602 42610 42700 42769 42794 42814 42845 42860 42887 42892 42918 42934 43001 43047 43055 43068 43105 43124 43187 43228 43258 43290 43327 43345 43387 43544 43569 43577 43649 43659 43724 43813 43818 43845 43911 43928-43929 43970 43977 43989 44005 44115 44131 44150-44151 44223 44243 44257 44262 44284 44359 44398 44482 44576 44652 44681 44792 44860 44879 44967 45013 45112 45118 45121 45143 45182 45265 45299 45334 45337 45386 45388 45412 45475 45482 45485 45502 45505 45511 45543 45564 45589 45627 45641 45646 45669 45687 45717 45823 45853 45865 45902 46009 46032 46056 46076 46080 46118 46135 46172 46193 46200 46203 46218 46234 46247 46287 46306 46364 46394 46437 46487 46544 46566 46603 46640 46664 46681 46734 46768 46776 46784 46800 46843 46874 46923 46933 46944 46967 46983 46997 47020 47022 47045 47137 47194 47223 47253 47364 47390 47414 47575 47580 47590 47629 47740 47758 47780 47842 47858 47894 47898 47903 47985 47994 48028 48061 48172 48238 48310 48335 48350 48362 48402 48519 48530 48545 48581 48607 48652 48658 48664 48705 48731 48792 48821 48870 48926 48943 48980 49064 49114 49128https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/654/A168?format=asciidefaultJ/A+A/654/A168/tablee1Modeled CBS reference valuesSpTypeSpectral Typesrc.spTypecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTeff[4000/7220] Effective TemperatureKphys.temperature.effectiveintScale[0.21/6.02] Solar-relative CBS scale factorarith.factorfloatConvBS[-2163.1/-77.8] Convective blueshift velocity (1)m/sphys.velocfloatJ/A+A/654/A168/tablee2Stellar parameters and resultsSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameName of the starmeta.id;meta.maincharGaiaDR2Gaia DR2 star ID (1)meta.idTeff[3296/6393] Effective Temperature (1)Kphys.temperature.effectiveintSpTypeSpectral Type (2)src.spTypecharGmag[3.13/13.46] GAIA G Magnitude (1)magphot.mag;em.optfloatvsini? Projected Rotational Velocity (3)m/sphys.veloc.rotatfloatnullableProt[9.4/58.4]? Rotation Period (4)dtime.periodfloatnullablelogR'HK[-5.55/-3.68]? CaII H/K activity indicator (5)phot.flux;arith.ratiofloatnullableNcoadd[3/9735] Number of coadded spectrameta.numberintS/N[28/18823]? Signal-to-Noise ratiostat.snrintnullableNlines[712/1226] Number of lines fitted linesmeta.numberintchi2PPearson Chi-square of 3rd signature fitstat.fit.param;meta.modelleddoubleScale[-38.01/24.19] Solar-relative CBS scale factorarith.factorfloate_Scale[0.01/3.19] Error on CBS scale factorstat.error;instr.scalefloat_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.main