2012AJ....143...92G


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.22CEST22:26:26

2012AJ....143...92G - Astron. J., 143, 92 (2012/April-0)

The third signature of granulation in bright-giant and supergiant stars.

GRAY D.F. and PUGH T.

Abstract (from CDS):

We investigated third-signature granulation plots for 18 bright giants and supergiants and one giant of spectral classes G0 to M3. These plots reveal the net granulation velocities, averaged over the stellar disk, as a function of depth. Supergiants show significant differences from the "standard" shape seen for lower-luminosity stars. Most notable is a striking reversal of slope seen for three of the nine supergiants, i.e., stronger lines are more blueshifted than weaker lines, opposite the solar case. Changes in the third-signature plot of α Sco (M1.5 Iab) with time imply granulation cells that penetrate only the lower portion of the photosphere. For those stars showing the standard shape, we derive scaling factors relative to the Sun that serve as a first-order measure of the strength of the granulation relative to the Sun. For G-type stars, the third-signature scale of the bright giants and supergiants is approximately 1.5 times as strong as in dwarfs, but for K stars, there in no discernible difference between higher-luminosity stars and dwarfs. Classical macroturbulence, a measure of the velocity dispersion of the granulation, increases with the third-signature-plot scale factors, but at different rates for different luminosity classes.

Abstract Copyright:

Journal keyword(s): convection - line: profiles - stars: atmospheres - stars: late-type - Sun: granulation - techniques: spectroscopic

CDS comments: Table 1: HR 2296 is a misprint for HR 2286.

Simbad objects: 28

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Number of rows : 28

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 * eta Cas PM* 00 49 06.2907161 +57 48 54.675740 4.04 4.02 3.44 2.94 2.58 F9V+M0-V 588 0
2 * tau Cet PM* 01 44 04.0834226 -15 56 14.926552 4.43 4.22 3.50 2.88 2.41 G8V 1064 1
3 * gam01 And SB* 02 03 53.9531 +42 19 47.009 4.22 3.30 2.10 1.16 0.47 K2+IIb 319 0
4 * alf Ari PM* 02 07 10.40570 +23 27 44.7032 4.29 3.17 2.01 1.15 0.54 K2-IIIbCa-1 599 1
5 * eps Eri BY* 03 32 55.8449634 -09 27 29.731165 5.19 4.61 3.73 3.00 2.54 K2V 1658 1
6 * iot Aur V* 04 56 59.6210887 +33 09 57.958479 6.00 4.22 2.69 1.63 0.81 K3II-III 262 0
7 * bet Cam * 05 03 25.0896309 +60 26 32.089527 5.57 4.95 4.02 3.33 2.86 G1Ib 161 0
8 * alf Ori s*r 05 55 10.30536 +07 24 25.4304 4.38 2.27 0.42 -1.17 -2.45 M1-M2Ia-Iab 1443 0
9 * mu. Gem LP* 06 22 57.62686 +22 30 48.8979 6.37 4.51 2.87 1.30 -0.08 M3IIIab 362 1
10 * eps Gem V* 06 43 55.9262590 +25 07 52.051484 5.85 4.39 2.98 2.01 1.40 G8Ib 378 0
11 * zet Mon * 08 08 35.6466280 -02 59 01.636060 6.02 5.30 4.33 3.60 3.11 G2Ib 136 0
12 * zet Cnc ** 08 12 12.72637 +17 38 51.9615   5.20   4.9   F8V+G0V 167 0
13 * zet01 Cnc ** 08 12 12.72637 +17 38 51.9615           F8V 155 0
14 * iot Cnc PM* 08 46 41.8219658710 +28 45 35.617935005   4.996 4.018     G8IIIaBa0.2 154 0
15 * eps Leo V* 09 45 51.0733004 +23 46 27.320834 4.23 3.79 2.98 2.36 1.93 G1IIIa 317 0
16 * 37 LMi * 10 38 43.2126896 +31 58 34.460669   5.494 4.677     G2.5IIIa 140 0
17 * eta Dra PM* 16 23 59.48594 +61 30 51.1699 4.35 3.65 2.74 2.12 1.66 G8-IIIab 275 0
18 * alf Sco ** 16 29 24.45970 -26 25 55.2094 4.08 2.75 0.91 -0.64 -1.87 M0.5Iab+B3V: 681 1
19 * bet Dra * 17 30 25.9616959 +52 18 04.999351 4.43 3.79 2.81 2.12 1.64 G2Ib-IIa 386 0
20 * tet Lyr * 19 16 22.0948728 +38 08 01.423443 6.87 5.64 4.38 3.51 2.93 K0II 184 0
21 * gam Aql * 19 46 15.5802908 +10 36 47.740788 5.93 4.23 2.72 1.65 0.87 K3II 416 0
22 * omi02 Cyg Al* 20 15 28.3216287393 +47 42 51.221859715 6.54 5.50 3.98 2.78 1.86 K7Ib-II+B1V 318 0
23 * 22 Vul Al* 20 15 30.2380607842 +23 30 32.032946807   6.192 5.176     G3Ib-II 194 0
24 * gam Cyg V* 20 22 13.7018357 +40 15 24.044963 3.44 2.90 2.23 1.74 1.40 F8Ib 541 0
25 * 41 Cyg V* 20 29 23.7356120 +30 22 06.796777 4.69 4.42 4.01 3.65 3.42 F5Ib-II 180 0
26 * 47 Cyg SB* 20 33 54.1882057656 +35 15 03.028103621   6.145 4.636     K6:Ib+B2.5: 95 1
27 * bet Aqr * 21 31 33.5317148 -05 34 16.232006 4.27 3.71 2.89 2.29 1.84 G0Ib 425 0
28 * alf Aqr * 22 05 47.0359315 -00 19 11.456766 4.65 3.90 2.94 2.27 1.76 G2Ib 416 0

    Equat.    Gal    SGal    Ecl

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2019.10.22-22:26:26

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