1636:
124:
zone. No standard pulsation model can be made to excite oscillations of the roAp type using the opacity mechanism. As the magnetic field appears to be important, research has taken this into account in deriving non-standard pulsation models. It has been suggested that the modes are driven by the
102:
amplitude of the pulsation, depending on the orientation of the axis to the line of sight, as it varies with rotation. The apparent link between the magnetic axis and the pulsation axis gives clues to the nature of the driving mechanism of the pulsations. As the roAp stars seem to occupy the
101:
The roAp stars oscillate in high-overtone, low-degree, non-radial pressure modes. The usual model that is used to explain the behavior of these pulsations is the oblique pulsator model. In this model the axis of pulsation is aligned with the magnetic axis, which can lead to modulation of the
125:
suppression of convection by the strong magnetic field near the magnetic poles of these stars, which would account for the alignment of the pulsation axis with the magnetic axis. An instability strip for the roAp stars has been calculated, which agreed with the positions on the
133:
Most roAp stars have been discovered using small telescopes to observe the small changes in amplitude caused by the pulsation of the star. However, it is also possible to observe such pulsations by measuring the variations in radial velocity of sensitive lines, such as
129:
of the roAp stars discovered up to that point, but predicted the existence of longer-period pulsators among the more evolved roAp stars. Such a pulsator was discovered in HD 177765, which has the longest pulsation period of any roAp star at 23.6 minutes.
824:
Shibahashi, Hiromoto; Takata, Masao (1993). "Theory for the
Distorted Dipole Modes of the Rapidly Oscillating AP Stars: A Refinement of the Oblique Pulsator Model".
1102:
154:
that are radiatively levitated high in the atmosphere are likely to be most sensitive to measuring the pulsation, whereas the lines of elements such as
146:. It is thought that the pulsations are of highest amplitude high in the atmospheres of these stars, where the density is lower. As a result, the
70:
1664:
756:
Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data
Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)".
1095:
1574:
86:
126:
85:
The roAp stars are sometimes referred to as rapidly oscillating α Canum
Venaticorum variables. Both the roAp stars and some
1537:
1392:
1223:
1088:
1213:
1354:
1616:
1413:
1144:
1445:
1437:
1387:
1246:
1233:
1621:
1382:
90:
1418:
1272:
1251:
1645:
1349:
1302:
1298:
1267:
1218:
35:
1669:
1493:
1277:
1185:
478:
1553:
1208:
1203:
1160:
1148:
1056:
997:
946:
905:
864:
833:
796:
765:
738:
388:
62:
43:
1423:
1611:
1584:
1164:
1471:
1359:
1046:
1015:
987:
1455:
1366:
1310:
1175:
1168:
1119:
110:
46:
1511:
1498:
1128:
1064:
1005:
954:
913:
872:
868:
804:
151:
114:
1321:
1155:
39:
1060:
1035:"Rapidly oscillating TESS A-F main-sequence stars: Are the roAp stars a distinct class?"
1001:
974:
Alentiev, D.; Kochukhov, O.; Ryabchikova, T.; Cunha, M.; Tsymbal, V.; Weiss, W. (2012).
950:
909:
837:
800:
769:
742:
158:, which gravitationally settle, are not expected to exhibit radial velocity variations.
1606:
1504:
1315:
1139:
147:
729:
Kurtz, D. W. (1978). "12.15 Minute Light
Variations in Przybylski's Star, HD 101065".
1658:
1558:
1241:
1111:
1019:
1010:
975:
959:
934:
918:
893:
641:
447:
103:
50:
1465:
1328:
495:
139:
66:
877:
852:
758:
VizieR On-line Data
Catalog: B/GCVS. Originally Published in: 2009yCat....102025S
1640:
1598:
107:
74:
1450:
1408:
892:
Balmforth, N. J.; Cunha, M. S.; Dolez, N.; Gough, D. O.; Vauclair, S. (2001).
809:
784:
568:
121:
42:
variations. The known periods range between 5 and 23 minutes. They lie in the
1485:
1479:
1069:
1034:
135:
113:, it has been suggested that the driving mechanism may be similar, i.e. the
118:
976:"Discovery of the longest period rapidly oscillating Ap star HD 177765★"
17:
273:
31:
1579:
1635:
1051:
992:
935:"A theoretical instability strip for rapidly oscillating Ap stars"
1080:
1460:
155:
143:
93:, but the roAp stars have very short periods less than an hour.
1084:
980:
Monthly
Notices of the Royal Astronomical Society: Letters
89:
lie on the δ Scuti instability strip and are magnetic
61:
The first roAp star to be discovered was HD 101065 (
1597:
1567:
1546:
1530:
1523:
1436:
1401:
1375:
1340:
1297:
1290:
1260:
1232:
1194:
1127:
1118:
1039:Monthly Notices of the Royal Astronomical Society
939:Monthly Notices of the Royal Astronomical Society
898:Monthly Notices of the Royal Astronomical Society
826:Publications of the Astronomical Society of Japan
789:Monthly Notices of the Royal Astronomical Society
73:, who saw 10–20-millimagnitude variations in the
69:using the 20-inch (510 mm) telescope at the
65:) in 1961. The oscillations were discovered by
142:. Some lines are not seen to pulsate, such as
1096:
8:
77:of the star with a period of 12.15 minutes.
894:"On the excitation mechanism in roAp stars"
1527:
1294:
1124:
1103:
1089:
1081:
165:
1068:
1050:
1009:
991:
958:
917:
876:
808:
28:Rapidly oscillating Ap stars (roAp stars)
721:
853:"The oblique pulsator model revisited"
851:Bigot, L.; Dziembowski, W. A. (2002).
731:Information Bulletin on Variable Stars
71:South African Astronomical Observatory
7:
34:that exhibit short-timescale rapid
25:
1634:
1011:10.1111/j.1745-3933.2011.01211.x
960:10.1046/j.1365-8711.2002.05377.x
919:10.1046/j.1365-8711.2001.04182.x
785:"Rapidly oscillating AP stars"
1:
1224:Blue large-amplitude pulsator
162:List of identified roAp stars
1665:Rapidly oscillating Ap stars
933:Cunha, Margarida S. (2002).
127:Hertzsprung–Russell diagram
117:mechanism operating in the
1686:
878:10.1051/0004-6361:20020824
857:Astronomy and Astrophysics
1630:
91:chemically peculiar stars
1273:Solar-like oscillations
1214:Slowly pulsating B-type
869:2002A&A...391..235B
810:10.1093/mnras/200.3.807
1350:Luminous blue variable
1181:Rapidly oscillating Ap
1033:Balona, L. A. (2022).
1070:10.1093/mnras/stac011
783:Kurtz, D. W. (1982).
30:are a subtype of the
1538:Rotating ellipsoidal
1446:AM Canum Venaticorum
1393:RS Canum Venaticorum
1575:α Canum Venaticorum
1061:2022MNRAS.510.5743B
1002:2012MNRAS.421L..82A
951:2002MNRAS.333...47C
910:2001MNRAS.323..362B
838:1993PASJ...45..617S
801:1982MNRAS.200..807K
770:2009yCat....102025S
743:1978IBVS.1436....1K
168:
150:that are formed by
1559:FK Comae Berenices
1355:R Coronae Borealis
1145:Classical cepheids
700:CN Tuc, HD 218495
686:BP Gru, HD 217522
672:MM Aqr, HD 213637
658:BI Mic, HD 203932
627:AW Cap, HD 196470
613:QR Tel, HD 193756
599:CK Oct, HD 190290
464:HI Lib, HD 134214
433:PP Vir, HD 122970
419:LZ Hya, HD 119027
166:
1652:
1651:
1617:Planetary transit
1593:
1592:
1514:
1507:
1488:
1474:
1456:Luminous red nova
1432:
1431:
1414:Gamma Cassiopeiae
1367:Yellow hypergiant
1363:
1331:
1324:
1286:
1285:
1172:
1152:
713:
712:
389:Przybylski's Star
346:AI Ant, HD 84041
332:IM Vel, HD 83368
318:LX Hya, HD 80316
290:UV Lep, HD 42659
259:BT Hyi, HD 19918
231:BN Cet, HD 12098
184:Period (minutes)
111:instability strip
63:Przybylski's Star
47:instability strip
16:(Redirected from
1677:
1639:
1638:
1528:
1510:
1503:
1484:
1470:
1388:FS Canis Majoris
1357:
1327:
1320:
1295:
1158:
1142:
1125:
1105:
1098:
1091:
1082:
1075:
1074:
1072:
1054:
1030:
1024:
1023:
1013:
995:
971:
965:
964:
962:
930:
924:
923:
921:
889:
883:
882:
880:
848:
842:
841:
821:
815:
814:
812:
780:
774:
773:
753:
747:
746:
726:
217:BW Cet, HD 9289
203:AP Scl, HD 6532
169:
21:
1685:
1684:
1680:
1679:
1678:
1676:
1675:
1674:
1655:
1654:
1653:
1648:
1641:Star portal
1633:
1626:
1622:W Ursae Majoris
1589:
1568:Magnetic fields
1563:
1542:
1519:
1428:
1397:
1383:Double periodic
1376:Eruptive binary
1371:
1342:
1336:
1282:
1256:
1228:
1196:
1195:Blue-white with
1190:
1132:
1114:
1109:
1079:
1078:
1032:
1031:
1027:
973:
972:
968:
932:
931:
927:
891:
890:
886:
850:
849:
845:
823:
822:
818:
782:
781:
777:
755:
754:
750:
728:
727:
723:
718:
164:
99:
87:α CVn variables
83:
59:
40:radial velocity
23:
22:
15:
12:
11:
5:
1683:
1681:
1673:
1672:
1667:
1657:
1656:
1650:
1649:
1631:
1628:
1627:
1625:
1624:
1619:
1614:
1609:
1603:
1601:
1595:
1594:
1591:
1590:
1588:
1587:
1582:
1577:
1571:
1569:
1565:
1564:
1562:
1561:
1556:
1550:
1548:
1544:
1543:
1541:
1540:
1534:
1532:
1525:
1521:
1520:
1518:
1517:
1516:
1515:
1508:
1505:Symbiotic nova
1496:
1491:
1490:
1489:
1477:
1476:
1475:
1463:
1458:
1453:
1448:
1442:
1440:
1434:
1433:
1430:
1429:
1427:
1426:
1421:
1419:Lambda Eridani
1416:
1411:
1405:
1403:
1399:
1398:
1396:
1395:
1390:
1385:
1379:
1377:
1373:
1372:
1370:
1369:
1364:
1352:
1346:
1344:
1338:
1337:
1335:
1334:
1333:
1332:
1325:
1313:
1307:
1305:
1292:
1288:
1287:
1284:
1283:
1281:
1280:
1275:
1270:
1264:
1262:
1258:
1257:
1255:
1254:
1252:Slow irregular
1249:
1244:
1238:
1236:
1230:
1229:
1227:
1226:
1221:
1216:
1211:
1206:
1200:
1198:
1192:
1191:
1189:
1188:
1183:
1178:
1173:
1153:
1136:
1134:
1122:
1116:
1115:
1112:Variable stars
1110:
1108:
1107:
1100:
1093:
1085:
1077:
1076:
1025:
986:(1): L82–L86.
966:
925:
884:
843:
816:
775:
748:
720:
719:
717:
714:
711:
710:
707:
704:
701:
697:
696:
693:
690:
687:
683:
682:
679:
676:
673:
669:
668:
665:
662:
659:
655:
654:
651:
648:
645:
638:
637:
634:
631:
628:
624:
623:
620:
617:
614:
610:
609:
606:
603:
600:
596:
595:
592:
589:
586:
582:
581:
578:
575:
572:
565:
564:
561:
558:
555:
551:
550:
547:
544:
541:
537:
536:
533:
530:
527:
523:
522:
519:
516:
513:
509:
508:
505:
502:
499:
492:
491:
488:
485:
482:
475:
474:
471:
468:
465:
461:
460:
457:
454:
451:
444:
443:
440:
437:
434:
430:
429:
426:
423:
420:
416:
415:
412:
409:
406:
402:
401:
398:
397:controversial
395:
392:
385:
384:
381:
378:
375:
371:
370:
367:
364:
361:
357:
356:
353:
350:
347:
343:
342:
339:
336:
333:
329:
328:
325:
322:
319:
315:
314:
311:
308:
305:
301:
300:
297:
294:
291:
287:
286:
283:
280:
277:
270:
269:
266:
263:
260:
256:
255:
252:
249:
246:
242:
241:
238:
235:
232:
228:
227:
224:
221:
218:
214:
213:
210:
207:
204:
200:
199:
196:
193:
190:
186:
185:
182:
181:Spectral type
179:
173:
163:
160:
148:spectral lines
98:
95:
82:
81:Classification
79:
58:
55:
24:
14:
13:
10:
9:
6:
4:
3:
2:
1682:
1671:
1668:
1666:
1663:
1662:
1660:
1647:
1643:
1642:
1637:
1629:
1623:
1620:
1618:
1615:
1613:
1610:
1608:
1605:
1604:
1602:
1600:
1596:
1586:
1583:
1581:
1578:
1576:
1573:
1572:
1570:
1566:
1560:
1557:
1555:
1552:
1551:
1549:
1547:Stellar spots
1545:
1539:
1536:
1535:
1533:
1531:Non-spherical
1529:
1526:
1522:
1513:
1509:
1506:
1502:
1501:
1500:
1497:
1495:
1492:
1487:
1483:
1482:
1481:
1478:
1473:
1469:
1468:
1467:
1464:
1462:
1459:
1457:
1454:
1452:
1449:
1447:
1444:
1443:
1441:
1439:
1435:
1425:
1422:
1420:
1417:
1415:
1412:
1410:
1407:
1406:
1404:
1400:
1394:
1391:
1389:
1386:
1384:
1381:
1380:
1378:
1374:
1368:
1365:
1361:
1356:
1353:
1351:
1348:
1347:
1345:
1339:
1330:
1326:
1323:
1319:
1318:
1317:
1314:
1312:
1309:
1308:
1306:
1304:
1300:
1296:
1293:
1289:
1279:
1276:
1274:
1271:
1269:
1268:Gamma Doradus
1266:
1265:
1263:
1259:
1253:
1250:
1248:
1245:
1243:
1240:
1239:
1237:
1235:
1231:
1225:
1222:
1220:
1219:PV Telescopii
1217:
1215:
1212:
1210:
1207:
1205:
1202:
1201:
1199:
1197:early spectra
1193:
1187:
1184:
1182:
1179:
1177:
1174:
1170:
1166:
1162:
1157:
1154:
1150:
1146:
1141:
1138:
1137:
1135:
1130:
1126:
1123:
1121:
1117:
1113:
1106:
1101:
1099:
1094:
1092:
1087:
1086:
1083:
1071:
1066:
1062:
1058:
1053:
1048:
1044:
1040:
1036:
1029:
1026:
1021:
1017:
1012:
1007:
1003:
999:
994:
989:
985:
981:
977:
970:
967:
961:
956:
952:
948:
944:
940:
936:
929:
926:
920:
915:
911:
907:
903:
899:
895:
888:
885:
879:
874:
870:
866:
862:
858:
854:
847:
844:
839:
835:
831:
827:
820:
817:
811:
806:
802:
798:
794:
790:
786:
779:
776:
771:
767:
763:
759:
752:
749:
744:
740:
736:
732:
725:
722:
715:
708:
705:
702:
699:
698:
694:
691:
688:
685:
684:
680:
677:
674:
671:
670:
666:
663:
660:
657:
656:
652:
649:
646:
643:
640:
639:
635:
632:
629:
626:
625:
621:
618:
615:
612:
611:
607:
604:
601:
598:
597:
593:
590:
587:
584:
583:
579:
576:
573:
570:
567:
566:
562:
559:
556:
553:
552:
548:
545:
542:
539:
538:
534:
531:
528:
525:
524:
520:
517:
514:
511:
510:
506:
503:
500:
497:
494:
493:
489:
486:
483:
480:
477:
476:
472:
469:
466:
463:
462:
458:
455:
452:
449:
446:
445:
441:
438:
435:
432:
431:
427:
424:
421:
418:
417:
413:
410:
407:
404:
403:
399:
396:
393:
390:
387:
386:
382:
379:
376:
373:
372:
368:
365:
362:
359:
358:
354:
351:
348:
345:
344:
340:
337:
334:
331:
330:
326:
323:
320:
317:
316:
312:
309:
306:
303:
302:
298:
295:
292:
289:
288:
284:
281:
278:
275:
272:
271:
267:
264:
261:
258:
257:
253:
250:
247:
244:
243:
239:
236:
233:
230:
229:
225:
222:
219:
216:
215:
211:
208:
205:
202:
201:
197:
194:
191:
188:
187:
183:
180:
177:
174:
171:
170:
161:
159:
157:
153:
149:
145:
141:
137:
131:
128:
123:
120:
116:
112:
109:
105:
104:main sequence
96:
94:
92:
88:
80:
78:
76:
72:
68:
64:
56:
54:
52:
51:main sequence
48:
45:
41:
37:
33:
32:Ap star class
29:
19:
1670:A-type stars
1632:
1512:Z Andromedae
1494:SW Sextantis
1472:Intermediate
1311:Herbig Ae/Be
1186:SX Phoenicis
1180:
1133:cepheid-like
1042:
1038:
1028:
983:
979:
969:
942:
938:
928:
901:
897:
887:
860:
856:
846:
829:
825:
819:
792:
788:
778:
761:
757:
751:
734:
730:
724:
678:A(p EuSrCr)
644:, HD 201601
633:Ap SrEu(Cr)
591:Ap Sr(EuCr)
571:, HD 176232
498:, HD 137949
481:, HD 137909
470:Ap SrEu(Cr)
456:Ap SrEu(Cr)
450:, HD 128898
425:Ap SrEu(Cr)
391:, HD 101065
282:Ap SrEu(Cr)
175:
140:praseodymium
132:
100:
97:Oscillations
84:
67:Donald Kurtz
60:
27:
26:
1554:BY Draconis
1438:Cataclysmic
1343:supergiants
1278:White dwarf
1247:Semiregular
1234:Long-period
1209:Beta Cephei
1204:Alpha Cygni
1161:BL Herculis
1149:Delta Scuti
1045:(4): 5743.
276:, HD 24712
167:roAp stars
106:end of the
75:light curve
36:photometric
1659:Categories
1612:Beta Lyrae
1585:SX Arietis
1451:Dwarf nova
1424:Wolf–Rayet
1341:Giants and
1322:FU Orionis
1165:W Virginis
1052:2109.02246
904:(2): 362.
795:(3): 807.
716:References
692:Ap (Si)Cr
619:Ap SrCrEu
585:HD 185256
560:Ap SrEuCr
554:HD 166473
546:Ap EuSrCr
540:HD 161459
526:HD 154708
518:A/F(p Eu)
512:HD 150562
504:Ap SrEuCr
405:HD 116114
352:Ap SrEuCr
338:Ap SrEuCr
327:11.4–23.5
324:Ap Sr(Eu)
310:Ap Sr(Eu)
296:Ap SrCrEu
265:Ap SrEuCr
251:Ap SrEuCr
209:Ap SrEuCr
189:HD 177765
178:magnitude
172:Star name
122:ionization
1599:Eclipsing
1499:Symbiotic
1486:Hypernova
1480:Supernova
1360:DY Persei
1299:Protostar
1120:Pulsating
1020:117092062
993:1112.4473
945:(1): 47.
577:F0p SrEu
374:HD 99563
360:HD 86181
304:HD 60435
245:HD 12932
136:neodymium
57:Discovery
1524:Rotating
1291:Eruptive
1176:RR Lyrae
1169:RV Tauri
1129:Cepheids
706:Ap EuSr
664:Ap SrEu
605:Ap EuSr
439:unknown
223:Ap SrCr
152:elements
119:hydrogen
18:BT Hydri
1329:T Tauri
1156:Type II
1057:Bibcode
998:Bibcode
947:Bibcode
906:Bibcode
865:Bibcode
863:: 235.
834:Bibcode
832:: 617.
797:Bibcode
766:Bibcode
739:Bibcode
115:opacity
108:δ Scuti
49:on the
44:δ Scuti
1580:Pulsar
1140:Type I
1018:
569:10 Aql
543:10.33
496:GZ Lib
422:10.02
366:Ap Sr
274:DO Eri
248:10.25
1607:Algol
1466:Polar
1409:Flare
1402:Other
1316:Orion
1261:Other
1047:arXiv
1016:S2CID
988:arXiv
737:: 1.
703:9.36
695:13.9
689:7.53
681:11.5
675:9.61
661:8.82
653:12.4
647:4.68
642:γ Equ
636:10.8
630:9.72
622:13.0
616:9.20
602:9.91
594:10.2
588:9.94
580:11.6
574:5.89
557:7.92
549:12.0
529:8.76
521:10.8
515:9.82
501:6.67
490:16.2
484:3.68
479:β CrB
467:7.46
453:3.20
448:α Cir
442:11.1
436:8.31
414:21.3
408:7.02
400:12.1
394:7.99
383:10.7
377:8.16
363:9.32
355:15.0
349:9.33
341:11.6
335:6.17
321:7.78
307:8.89
293:6.77
279:6.00
268:14.5
262:9.34
254:11.6
240:7.61
234:8.07
226:10.5
220:9.38
206:8.45
198:23.6
1646:List
1461:Nova
1301:and
1242:Mira
735:1436
709:7.4
667:5.9
650:F0p
608:7.3
563:8.8
535:8.0
507:8.3
487:F0p
473:5.6
459:6.8
428:8.7
369:6.2
313:9.7
299:9.7
285:6.2
212:7.1
192:9.1
156:iron
144:iron
1303:PMS
1131:and
1065:doi
1043:510
1006:doi
984:421
955:doi
943:333
914:doi
902:323
873:doi
861:391
805:doi
793:200
532:Ap
411:Ap
380:F0
237:F0
195:Ap
138:or
38:or
1661::
1644:*
1167:,
1163:,
1147:,
1063:.
1055:.
1041:.
1037:.
1014:.
1004:.
996:.
982:.
978:.
953:.
941:.
937:.
912:.
900:.
896:.
871:.
859:.
855:.
830:45
828:.
803:.
791:.
787:.
764:.
760:.
733:.
53:.
1362:)
1358:(
1171:)
1159:(
1151:)
1143:(
1104:e
1097:t
1090:v
1073:.
1067::
1059::
1049::
1022:.
1008::
1000::
990::
963:.
957::
949::
922:.
916::
908::
881:.
875::
867::
840:.
836::
813:.
807::
799::
772:.
768::
762:1
745:.
741::
176:V
20:)
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