2024ApJ...974..232O

Query : 2024ApJ...974..232O

2024ApJ...974..232O - Astrophys. J., 974, 232 (2024/October-3)

The Rise of the r-process in the Gaia-Sausage/Enceladus Dwarf Galaxy.

OU X., JI A.P., FREBEL A., NAIDU R.P. and LIMBERG G.

Abstract (from CDS):

Neutron star mergers (NSMs) produce r-process elements after a time-delayed inspiral process. Once a significant number of NSMs are present in a galaxy, r-process elements, such as Eu, are expected to significantly increase with time. Yet, there have been limited observational data in support of Eu increasing within Local Group galaxies. We have obtained high-resolution Magellan/MIKE observations of 43 metal-poor stars in the Gaia-Sausage/Enceladus (GSE) tidally disrupted galaxy with -2.5 < [Fe/H] < -1. For the first time, we find a clear rise in [Eu/Mg] with increasing [Mg/H] within one galaxy. We use a simple chemical evolution model to study how such a rise can result from the interplay of prompt and delayed r-process enrichment events. Delayed r-process sources are required to explain the rise and subsequent leveling off of [Eu/Mg] in this disrupted galaxy. However, the rise may be explained by delayed r-process sources with either short (∼10 Myr) or long (∼500 Myr) minimum delay times. Future studies on the nature of r-process sources and their enrichment processes in the GSE will require additional stars in the GSE at even lower metallicities than the present study.

Abstract Copyright: © 2024. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): R-process - Galactic archaeology - Chemical enrichment

Simbad objects: 51

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Number of rows : 51
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 LAMOST J002517.55+160238.4 * 00 25 17.5560363603 +16 02 38.432374676           ~ 2 0
2 UCAC4 456-000862 Pe* 00 40 00.3099085448 +01 01 36.679536784   13.937 13.058 12.896   ~ 6 0
3 Gaia DR3 2472646349146818816 * 00 59 31.4358677334 -10 58 15.880511929           ~ 1 0
4 UCAC4 457-001461 RG* 01 07 27.0268727773 +01 19 27.556004636   13.933 12.932 12.897   ~ 12 0
5 LAMOST J012425.38+064339.8 * 01 24 25.3819825235 +06 43 39.878687416           ~ 2 0
6 UCAC4 461-002049 Pe* 01 30 13.9109377192 +02 07 07.697154527   14.423 13.500 13.420   ~ 7 0
7 UCAC4 207-001420 Pe* 01 31 18.4410252264 -48 45 35.200819728   14.311 13.462 13.366   ~ 4 0
8 UCAC4 196-001702 Pe* 01 51 29.1100277919 -50 49 12.641450839   14.748 13.842 13.873   ~ 3 0
9 UCAC2 31097957 RG* 01 56 29.6181796200 -01 50 45.796263972   13.192 12.045 11.85 10.85 ~ 17 0
10 TYC 4686-777-1 RG* 01 59 39.1517379960 -02 42 49.548203460   12.698 11.697     ~ 17 0
11 2MASS J02324042-3708110 Pe* 02 32 40.4232587568 -37 08 11.028982632   14.624 13.702 12.9 12.547 CEMP 11 0
12 Gaia DR3 31707926776039680 * 02 53 00.0625978906 +13 07 45.491854817           ~ 1 0
13 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 7988 0
14 Gaia DR3 5152929864265512448 * 03 08 52.1011490941 -16 49 16.284564468           ~ 1 0
15 UCAC4 214-003011 Pe* 03 10 38.9010857640 -47 17 25.274876820   14.247 13.453 13.291   ~ 10 0
16 UCAC4 417-004313 Pe* 03 32 15.6932211361 -06 44 29.695891613   14.480 13.544 13.423   ~ 8 0
17 Gaia DR3 3257948717988018304 * 03 59 35.0639463311 +00 57 10.646914612           ~ 1 0
18 UCAC4 189-004229 Pe* 04 21 29.2407219536 -52 19 57.774323254   13.967 12.966 12.630   ~ 3 0
19 UCAC4 139-003877 Pe* 04 25 15.2140297262 -62 13 20.929821504   13.862 13.040 12.932   ~ 8 0
20 2MASS J04322842-2544487 Pe* 04 32 28.4285851972 -25 44 48.726204916           ~ 2 0
21 UCAC4 181-004567 Pe* 04 35 43.1548608044 -53 55 09.285559745   13.363 12.514 12.345   ~ 7 0
22 UCAC4 250-005434 Pe* 04 52 59.1381250331 -40 08 56.920238692   13.900 12.966 12.817   ~ 8 0
23 UCAC4 215-005421 Pe* 05 00 17.5576858417 -47 06 59.578046313   14.336 13.341 13.149   ~ 4 0
24 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 19090 0
25 2MASS J05290344-6105446 Pe* 05 29 03.4594705274 -61 05 44.562620625           ~ 4 0
26 UCAC4 321-008277 Pe* 05 45 52.4890124631 -25 56 38.297622205   13.624   12.777   ~ 4 0
27 UCAC4 315-009257 Pe* 05 59 47.3738878076 -27 08 14.000807423   13.923 12.892 12.794   ~ 4 0
28 UCAC4 187-007212 Pe* 06 07 08.1718105800 -52 46 00.089060700   13.917 13.032 12.966   ~ 4 0
29 2MASS J08263144-7955131 Pe* 08 26 31.4510386163 -79 55 13.011538736           ~ 2 0
30 2MASS J08382975-7114407 Pe* 08 38 29.7654969936 -71 14 40.757297604           ~ 3 0
31 GrW 170817 GWE 13 09 48.0850 -23 22 53.343           ~ 2683 0
32 NAME LMS-1 Stream St* 13 14.5 +17 56           ~ 63 0
33 UCAC4 424-059793 Pe* 14 23 13.7824460304 -05 20 16.518214932   14.107 12.664 12.584   ~ 10 0
34 TYC 1478-659-1 RG* 14 53 08.7214462824 +16 11 04.053153840   12.26 11.30     ~ 16 0
35 Z 318-18 G 15 09 08.0 +67 13 21   13.60 10.6     ~ 1459 0
36 2MASS J15185770+0134483 Pe* 15 18 57.7024466843 +01 34 48.275571084           ~ 7 0
37 UCAC4 346-078965 Pe* 16 07 06.2236525292 -20 50 00.198943116   15.231 13.659 13.306   ~ 4 0
38 UCAC4 433-068785 Pe* 16 57 51.4337673910 -03 33 20.297847027   14.536 13.181 12.941   ~ 7 0
39 Z 300-12 G 17 20 14.335 +57 55 16.39   12.40 10.6     ~ 1428 1
40 2MASS J18202018-3218139 Pe* 18 20 20.1881021464 -32 18 13.931923550           ~ 4 0
41 2MASS J19144623-2211377 * 19 14 46.2374244747 -22 11 37.757193455           ~ 4 0
42 2MASS J20551529-0054163 Pe* 20 55 15.3018251315 -00 54 16.080458894           ~ 6 0
43 2MASS J21201351-3354026 Pe* 21 20 13.5160430010 -33 54 02.597692358           ~ 4 0
44 Gaia DR3 2733469542550276352 * 22 39 25.1694454500 +15 48 44.288771856           ~ 1 0
45 2MASS J23152484+1216037 RG* 23 15 24.8390837184 +12 16 03.773717904           ~ 10 0
46 2MASS J23172466+1119023 RG* 23 17 24.6625071984 +11 19 02.307987156           ~ 7 0
47 LAMOST J232724.54+042637.7 * 23 27 24.5415461929 +04 26 37.811698675           ~ 2 0
48 Gaia DR3 2632995998205049216 * 23 30 29.3124099446 -05 23 43.729146013           ~ 1 0
49 Gaia DR3 2765074076578453760 * 23 37 14.1750411268 +13 21 56.975293549           ~ 1 0
50 NAME Local Group GrG ~ ~           ~ 9325 0
51 NAME Gaia Enceladus-Sausage St* ~ ~           ~ 860 0

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