31:
1379:
172:
spectral classes (M, C and S) with a poorly expressed periodicity, i.e. with a different duration of individual cycles (which leads to the impossibility of predicting the epochs of maximum and minimum brightness), or with the replacement of periodical changes by slow irregular variations, or even by
140:
spectral classes (M, C and S), which retain periodicity with comparative stability and possess, as a rule, small (less than 2.5) light-variation amplitudes. Amplitudes and forms of light curves are usually liable to strong variations from period to period. Many of these stars differ from Mira Ceti
181:
Semiregular late-type (M, C, S or Me, Ce, Se) giants with poorly defined periodicity (mean cycles in the range of 20 to 2300 days) or with alternating intervals of periodic and slow irregular changes, and even with light constancy intervals. Every star of this type may usually be assigned a certain
149:
Semiregular late-type (M, C, S or Me, Ce, Se) giants displaying persistent periodicity and usually small (<2.5 mag in V) light amplitudes. Amplitudes and light-curve shapes generally vary and periods are in the range of 35–1200 days. Many of these stars differ from Miras only by showing smaller
670:
Soszyński, I.; Udalski, A.; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Wyrzykowski, Ł.; Szewczyk, O.; Ulaczyk, K.; Poleski, R. (2009). "The
Optical Gravitational Lensing Experiment. The OGLE-III Catalog of Variable Stars. IV. Long-Period Variables in the Large Magellanic Cloud".
88:
The semiregular variable stars have been sub-divided into four categories for many decades, with a fifth related group defined more recently. The original definitions of the four main groups were formalised in 1958 at the tenth general assembly of the
708:
Soszynski, I.; Dziembowski, W. A.; Udalski, A.; Kubiak, M.; Szymanski, M. K.; Pietrzynski, G.; Wyrzykowski, L.; Szewczyk, O.; Ulaczyk, K. (2007). "The
Optical Gravitational Lensing Experiment. Period--Luminosity Relations of Variable Red Giant Stars".
248:
Semiregular variable giants and supergiants of F, G, or K spectral types, sometimes with emission lines in their spectra. Amplitudes of light variation are in the range from 0.1 to 4 mag, and the range of periods is from 30 to 1100
329:
events have shown that essentially all cool evolved stars are variable, with the coolest stars showing very large amplitudes and warmer stars showing only micro-variations. The semiregular variable stars fall on one of five main
341:
Many semiregular variables show long secondary periods around ten times the main pulsation period, with amplitudes of a few tenths of a magnitude at visual wavelengths. The cause of the pulsations is not known.
309:
heading. In other situations, the term is expanded to cover almost all cool pulsating stars. The semi-regular giant stars are closely related to the Mira variables: Mira stars generally pulsate in the
68:
showing considerable periodicity in its light changes, accompanied or sometimes interrupted by various irregularities. Periods lie in the range from 20 to more than 2000
182:
mean period (cycle), which is the value given in the
Catalogue. In a number of cases, the simultaneous presence of two or more periods of light variation is observed
269:
218:
Spectral-type (M, C, S or Me, Ce, Se) supergiants with amplitudes of about 1 mag and periods of light variation from 30 days to several thousand days.
587:
845:
265:
257:
443:
288:
261:
475:
154:
186:
392:
by the GCVS, but reported to be of SRb type by later research. These four are all class M giants, although some SRb variables are
97:(GCVS) has updated the definitions with some additional information and provided newer reference stars where old examples such as
334:
sequences identified, differing from the Mira variables only in pulsating in an overtone mode. The closely related OSARG (
17:
173:
the constancy of brightness. Some of them are characterised by a certain mean value of the period, given in the catalogue.
1407:
583:
94:
838:
470:
1317:
90:
76:
may be rather different and variable with each cycle. The amplitudes may be from several hundredths to several
331:
284:
Semiregular pulsating red giants with short period (several days to a month), probably high-overtone pulsators
1280:
1135:
966:
831:
956:
1301:
1097:
923:
1359:
1156:
887:
326:
1188:
1180:
1130:
976:
480:
301:
The semiregular variable stars, particularly the SRa and SRb sub-classes, are often grouped with the
813:
1364:
1125:
407:
Catalogued SRc stars are less numerous, but include some of the brightest stars in the sky such as
1161:
1015:
994:
420:
389:
748:
The
Society for Astronomical Sciences 25th Annual Symposium on Telescope Science. Held May 23–25
1388:
1092:
1045:
1041:
1010:
961:
322:
1236:
1020:
928:
773:
Otero, S. A.; Moon, T. (December 2006). "The
Characteristic Period of Pulsation of β Gruis".
449:
Most SRS variables have been discovered in deep large-scale surveys, but the naked-eye stars
415:. Although SRc stars are defined as being supergiants, a number of them have giant spectral
1341:
442:. Others are classified as giant stars, but the brightest example is the seventh-magnitude
365:
is listed as the next-brightest SRa example, but it is suggested that it may actually be an
1296:
951:
946:
903:
891:
782:
755:
728:
690:
634:
306:
8:
1354:
1327:
1166:
907:
191:
786:
759:
732:
694:
638:
1214:
1102:
718:
680:
652:
624:
77:
1198:
1109:
1053:
918:
911:
862:
647:
612:
439:
366:
656:
1254:
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871:
642:
532:
435:
416:
311:
579:
1064:
898:
450:
431:
1349:
1247:
1058:
882:
412:
537:
520:
1401:
984:
854:
818:
350:
302:
65:
53:
30:
1208:
1071:
377:
253:
98:
1383:
393:
358:
73:
34:
1193:
1151:
458:
454:
427:
408:
397:
385:
381:
362:
61:
38:
1228:
1222:
746:
Watson, C. L. (2006). "The
International Variable Star Index (VSX)".
611:
Nicholls, C. P.; Wood, P. R.; Cioni, M.-R. L.; Soszyński, I. (2009).
401:
373:
354:
222:
57:
45:
803:
315:
226:
808:
775:
The
Journal of the American Association of Variable Star Observers
723:
685:
629:
141:
type stars only owing to the smaller amplitude of light variation.
823:
707:
369:, which would make it by far the brightest member of that class.
338:
small amplitude red giant) variables pulsate in an unknown mode.
819:
OGLE Atlas of
Variable Star Light Curves - Semiregular Variables
1322:
669:
372:
There are numerous naked-eye SRb stars, with third-magnitude
353:
is the brightest SRa variable, and also an eclipsing binary.
1203:
384:
are also third-magnitude SRb stars at maximum brightness.
335:
1378:
610:
69:
804:
EU Delphini and the Small-Amplitude
Pulsating Red Giants
525:
617:Monthly Notices of the Royal Astronomical Society
1399:
588:Sternberg Astronomical Institute, Moscow, Russia
613:"Long Secondary Periods in variable red giants"
839:
238:semi-regular variable giants and super-giants
814:Pulsating variable stars and the H-R diagram
314:; semiregular giants pulsate in one or more
476:Low-dimensional chaos in stellar pulsations
388:is a second magnitude star classified as a
846:
832:
80:(usually 1-2 magnitudes in the V filter).
772:
722:
684:
646:
628:
536:
376:being the brightest listed in the GCVS.
518:
29:
574:
572:
570:
568:
419:and some such as α Her are known to be
14:
1400:
745:
566:
564:
562:
560:
558:
556:
554:
552:
550:
548:
521:"27. Commission des Etoiles Variables"
426:Many SRd stars are extremely luminous
827:
766:
606:
604:
514:
512:
510:
508:
506:
504:
502:
500:
498:
496:
240:belonging to spectral classes F, G, K
663:
584:General Catalogue of Variable Stars
545:
361:with a maximum magnitude of 4.95.
95:General Catalogue of Variable Stars
24:
853:
739:
601:
493:
471:List of semiregular variable stars
345:
204:semi-regular variable super-giants
64:of intermediate and late (cooler)
25:
1419:
797:
701:
83:
1377:
648:10.1111/j.1365-2966.2009.15401.x
91:International Astronomical Union
332:period-luminosity relationship
105:Semiregular variable subtypes
13:
1:
967:Blue large-amplitude pulsator
486:
37:of semiregular variable star
296:
166:semi-regular variable giants
134:semi-regular variable giants
7:
464:
321:Photometric studies in the
10:
1424:
1408:Semiregular variable stars
430:, including the naked-eye
327:gravitational microlensing
72:, while the shapes of the
1373:
1340:
1310:
1289:
1273:
1266:
1179:
1144:
1118:
1083:
1040:
1033:
1003:
975:
937:
870:
861:
538:10.1017/S0251107X00020988
481:Variable star designation
101:have been re-classified.
50:semiregular variable star
580:"GCVS Variability Types"
519:Kukarkin, B. V. (2016).
400:or S-type stars such as
1016:Solar-like oscillations
957:Slowly pulsating B-type
421:asymptotic giant branch
390:slow irregular variable
357:is an SRa variable and
1093:Luminous blue variable
924:Rapidly oscillating Ap
323:Large Magellanic Cloud
41:
33:
27:Type of variable star
1281:Rotating ellipsoidal
1189:AM Canum Venaticorum
1136:RS Canum Venaticorum
307:long-period variable
18:Semiregular variable
1318:α Canum Venaticorum
787:2006JAVSO..34..156O
760:2006SASS...25...47W
733:2007AcA....57..201S
695:2009AcA....59..239S
639:2009MNRAS.399.2063N
106:
1302:FK Comae Berenices
1098:R Coronae Borealis
888:Classical cepheids
461:are also members.
417:luminosity classes
104:
42:
1395:
1394:
1360:Planetary transit
1336:
1335:
1257:
1250:
1231:
1217:
1199:Luminous red nova
1175:
1174:
1157:Gamma Cassiopeiae
1110:Yellow hypergiant
1106:
1074:
1067:
1029:
1028:
915:
895:
367:RV Tauri variable
294:
293:
285:
250:
241:
219:
211:
183:
174:
151:
142:
16:(Redirected from
1415:
1382:
1381:
1271:
1270:
1253:
1246:
1227:
1213:
1131:FS Canis Majoris
1100:
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1063:
1038:
1037:
901:
885:
868:
867:
848:
841:
834:
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824:
791:
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711:Acta Astronomica
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673:Acta Astronomica
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661:
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632:
608:
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576:
543:
542:
540:
516:
312:fundamental mode
283:
247:
236:
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210:spectral classes
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150:light amplitudes
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132:
107:
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21:
1423:
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1413:
1412:
1398:
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1384:Star portal
1376:
1369:
1365:W Ursae Majoris
1332:
1311:Magnetic fields
1306:
1285:
1262:
1171:
1140:
1126:Double periodic
1119:Eruptive binary
1114:
1085:
1079:
1025:
999:
971:
939:
938:Blue-white with
933:
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348:
346:Bright examples
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190:
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123:
119:GCVS definition
86:
28:
23:
22:
15:
12:
11:
5:
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1248:Symbiotic nova
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1196:
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1162:Lambda Eridani
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1128:
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1120:
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995:Slow irregular
992:
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855:Variable stars
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799:
798:External links
796:
793:
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781:(2): 156–164.
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491:
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303:Mira variables
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113:IAU definition
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84:Classification
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1290:Stellar spots
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1274:Non-spherical
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1011:Gamma Doradus
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962:PV Telescopii
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948:
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942:
940:early spectra
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590:. 12 Feb 2009
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66:spectral type
63:
59:
55:
54:variable star
51:
47:
40:
36:
32:
19:
1375:
1255:Z Andromedae
1237:SW Sextantis
1215:Intermediate
1054:Herbig Ae/Be
989:
929:SX Phoenicis
876:cepheid-like
778:
774:
768:
751:
747:
741:
714:
710:
703:
676:
672:
665:
620:
616:
592:. Retrieved
528:
524:
448:
425:
406:
394:carbon stars
371:
349:
340:
325:looking for
320:
300:
237:
207:
203:
169:
165:
137:
133:
93:(IAU). The
87:
74:light curves
52:, a type of
49:
43:
1297:BY Draconis
1181:Cataclysmic
1086:supergiants
1021:White dwarf
990:Semiregular
977:Long-period
952:Beta Cephei
947:Alpha Cygni
904:BL Herculis
892:Delta Scuti
623:(4): 2063.
531:: 398–431.
428:hypergiants
359:S-type star
35:Light curve
1355:Beta Lyrae
1328:SX Arietis
1194:Dwarf nova
1167:Wolf–Rayet
1084:Giants and
1065:FU Orionis
908:W Virginis
679:(3): 239.
594:2010-11-24
487:References
409:Betelgeuse
305:under the
78:magnitudes
62:supergiant
39:Betelgeuse
1342:Eclipsing
1242:Symbiotic
1229:Hypernova
1223:Supernova
1103:DY Persei
1042:Protostar
863:Pulsating
724:0710.2780
686:0910.1354
630:0907.2975
316:overtones
297:Pulsation
116:GCVS code
46:astronomy
1402:Category
1267:Rotating
1034:Eruptive
919:RR Lyrae
912:RV Tauri
872:Cepheids
809:Y Lyncis
657:19019968
465:See also
451:V428 And
436:V509 Cas
396:such as
122:Standard
1072:T Tauri
899:Type II
783:Bibcode
756:Bibcode
729:Bibcode
717:: 201.
691:Bibcode
635:Bibcode
423:stars.
110:Subtype
56:, is a
1323:Pulsar
883:Type I
754:: 47.
655:
459:EL Psc
457:, and
455:AV Ari
444:LU Aqr
438:, and
402:Pi Gru
398:UU Aur
355:GZ Peg
289:AU Ari
270:SV UMa
266:SX Her
262:AG Aur
258:UU Her
227:RW Cyg
192:RR CrB
187:AF Cyg
124:stars
1350:Algol
1209:Polar
1152:Flare
1145:Other
1059:Orion
1004:Other
719:arXiv
681:arXiv
653:S2CID
625:arXiv
440:ο Cen
432:ρ Cas
413:α Her
386:β Gru
382:ρ Per
378:σ Lib
374:L Pup
363:T Cen
351:η Gem
254:S Vul
223:μ Cep
155:Z Aqr
99:S Vul
58:giant
1389:List
1204:Nova
1044:and
985:Mira
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177:SRB
170:late
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129:SRa
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