Sagittarius A* cluster - Misplaced Pages

Star cluster orbiting Sagittarius A*

The Sagittarius A* cluster is the cluster of stars in close orbit around Sagittarius A*, the supermassive black hole at the center of the Milky Way (in the Galactic Center). The individual stars are often listed as "S-stars", but their names and IDs are not formalized, and stars can have different numbers in different catalogues.

One of the most studied stars is S2, a relatively bright star that also passes close by Sgr A*.

As of 2020, S4714 is the current record holder of closest approach to Sagittarius A*, at about 12.6 astronomical units (1.88×10 km), almost as close as Saturn gets to the Sun, traveling at about 8% of the speed of light. These figures given are approximate, the formal uncertainties being 12.6±9.3 au and 23928±8840 km/s. Its orbital period is 12 years, but an extreme eccentricity of 0.985 gives it the close approach and high velocity.

List of stars

The inferred orbits of stars around the supermassive black hole Sagittarius A* at the Milky Way's center are according to Gillessen et al. 2017, with the exception of S2 which is from GRAVITY 2019, S62 which is from Peißker et al. Jan 2020, and S4711 up to S4715, which are also from Peißker et al., Aug 2020.

Here id1 is the star's name in the Gillessen catalog and id2 in the catalog of the University of California, Los Angeles. a, e, i, Ω and ω are standard orbital elements, with a measured in arcseconds. Tp is the epoch of pericenter passage, P is the orbital period in years and Kmag is the K-band apparent magnitude of the star. q and v are the pericenter distance in AU and pericenter speed in percent of the speed of light, and Δ indicates the standard deviation of the associated quantities.

id1	id2	Other name	Spectral class	Mass (Solar masses)	Temperature (K)	a	Δa	e	Δe	i (°)	Δi	Ω (°)	ΔΩ	ω (°)	Δω	Tp (yr)	ΔTp	P (yr)	ΔP	Kmag	q (AU)	Δq	v (%c)	Δv	Radius (Solar radii)
S1	S0-1		B0-2 V			0.5950	0.0240	0.5560	0.0180	119.14	0.21	342.04	0.32	122.30	1.40	2001.800	0.150	166.0	5.8	14.70	2160.7	6.7	0.55	0.03	4.49
S2	S0-2		B0-2 V	14		0.1251	0.0001	0.8843	0.0001	133.91	0.05	228.07	0.04	66.25	0.04	2018.379	0.001	16.0518	0.0	13.95	118.4	0.2	2.56	0.00	6.36
S4	S0-3		B0-2 V			0.3570	0.0037	0.3905	0.0059	80.33	0.08	258.84	0.07	290.80	1.50	1957.400	1.200	77.0	1.0	14.40	1779.7	25.1	0.57	0.01
S6	S0-7		B0-2 V			0.6574	0.0006	0.8400	0.0003	87.24	0.06	85.07	0.12	116.23	0.07	2108.610	0.030	192.0	0.2	15.40	860.3	4.4	0.94	0.00	4.53
S8	S0-4		B0-2 V			0.4047	0.0014	0.8031	0.0075	74.37	0.30	315.43	0.19	346.70	0.41	1983.640	0.240	92.9	0.4	14.50	651.7	22.5	1.07	0.01	4.47
S9	S0-5		B0-2 V			0.2724	0.0041	0.6440	0.0200	82.41	0.24	156.60	0.10	150.60	1.00	1976.710	0.920	51.3	0.7	15.10	793.2	36.9	0.93	0.02
S10	S0-6	12	K5 III																	14.26
S12	S0-19		B4-9 V			0.2987	0.0018	0.8883	0.0017	33.56	0.49	230.10	1.80	317.90	1.50	1995.590	0.040	58.9	0.2	15.50	272.9	2.0	1.69	0.01
S13	S0-20		B4-9 V			0.2641	0.0016	0.4250	0.0023	24.70	0.48	74.50	1.70	245.20	2.40	2004.860	0.040	49.0	0.1	15.80	1242.0	2.4	0.69	0.01
S14	S0-16		B4-9 V			0.2863	0.0036	0.9761	0.0037	100.59	0.87	226.38	0.64	334.59	0.87	2000.120	0.060	55.3	0.5	15.70	56.0	3.8	3.83	0.06	3.1789
S17			K0 III		5,000	0.3559	0.0096	0.3970	0.0110	96.83	0.11	191.62	0.21	326.00	1.90	1991.190	0.410	76.6	1.0	15.30	1755.3	16.4	0.57	0.02	9
S18	S0-18					0.2379	0.0015	0.4710	0.0120	110.67	0.18	49.11	0.18	349.46	0.66	1993.860	0.160	41.9	0.2	16.70	1029.3	3.8	0.77	0.01
S19	S0-28		K-M			0.5200	0.0940	0.7500	0.0430	71.96	0.35	344.60	0.62	155.20	2.30	2005.390	0.160	135.0	14.0	16.00	1063.3	4.5	0.83	0.20
S21						0.2190	0.0017	0.7640	0.0140	58.80	1.00	259.64	0.62	166.40	1.10	2027.400	0.170	37.0	0.3	16.90	422.7	3.6	1.32	0.02
S22						1.3100	0.2800	0.4490	0.0880	105.76	0.95	291.70	1.40	95.00	20.00	1996.900	10.200	540.0	63.0	16.60	5903.7	9.7	0.32	0.10
S23						0.2530	0.0120	0.5600	0.1400	48.00	7.10	249.00	13.00	39.00	6.70	2024.700	3.700	45.8	1.6	17.80	910.5	1.6	0.85	0.06
S24	S0-26					0.9440	0.0480	0.8970	0.0049	103.67	0.42	7.93	0.37	290.00	15.00	2024.500	0.030	331.0	16.0	15.60	795.3	30.8	0.99	0.07
S27	S0-27		K3 III																	15.74
S29						0.4280	0.0190	0.7280	0.0520	105.80	1.70	161.96	0.80	346.50	5.90	2025.960	0.940	101.0	2.0	16.70	952.2	67.4	0.87	0.05
S31	S0-8		B4-9 V			0.4490	0.0100	0.5497	0.0025	109.03	0.27	137.16	0.30	308.00	3.00	2018.070	0.140	108.0	1.2	15.70	1653.7	14.6	0.63	0.02
S33	S0-33					0.6570	0.0260	0.6080	0.0640	60.50	2.50	100.10	5.50	303.70	1.60	1928.000	12.000	192.0	5.2	16.00	2106.5	179.7	0.56	0.03
S38	S0-38		M III	5.9713	3,330	0.1416	0.0002	0.8201	0.0007	171.10	2.10	101.06	0.24	17.99	0.25	2003.190	0.010	19.2	0.0	17.00	208.4	1.5	1.91	0.01	185.84
S39						0.3700	0.0150	0.9236	0.0021	89.36	0.73	159.03	0.10	23.30	3.80	2000.060	0.060	81.1	1.5	16.80	231.2	3.3	1.86	0.09
S42						0.9500	0.1800	0.5670	0.0830	67.16	0.66	196.14	0.75	35.80	3.20	2008.240	0.750	335.0	58.0	17.50	3364.4	24.8	0.44	0.13
S54						1.2000	0.8700	0.8930	0.0780	62.20	1.40	288.35	0.70	140.80	2.30	2004.460	0.070	477.0	199.0	17.50	1050.2	1.9	0.86	0.78
S55	S0-102		B0-2 V			0.1078	0.0010	0.7209	0.0077	150.10	2.20	325.50	4.00	331.50	3.90	2009.340	0.040	12.8	0.1	17.50	246.1	4.1	1.70	0.02
S60						0.3877	0.0070	0.7179	0.0051	126.87	0.30	170.54	0.85	29.37	0.29	2023.890	0.090	87.1	1.4	16.30	894.5	1.7	0.89	0.02
S62			B0-2 V	6.1		0.0897	0.00005	0.9760	0.0020	72.76	4.58	122.61	0.57	42.62	0.40	2003.330	0.010	9.9	0.0	16.10	16.4	1.5	7.03	0.04	3.8
S66	S1-2	GEN-0.06-1.01	O-B			1.5020	0.0950	0.1280	0.0430	128.50	1.60	92.30	3.20	134.00	17.00	1771.000	38.000	664.0	37.0	14.80	10712.4	620.5	0.21	0.02
S67	S1-3		O-B			1.1260	0.0260	0.2930	0.0570	136.00	1.10	96.50	6.40	213.50	1.60	1705.000	22.000	431.0	10.0	12.10	6511.2	360.6	0.29	0.01
S71	S0-71					0.9730	0.0400	0.8990	0.0130	74.00	1.30	35.16	0.86	337.80	4.90	1695.000	21.000	346.0	11.0	16.10	803.8	1.4	0.99	0.06
S83	S0-15	W5	O9-9.5 V		33,000	1.4900	0.1900	0.3650	0.0750	127.20	1.40	87.70	1.20	203.60	6.00	2046.800	6.300	656.0	69.0	13.60	7738.6	22.5	0.27	0.05	7.5
S85			M0 III	9.178	3,800	4.6000	3.3000	0.7800	0.1500	84.78	0.29	107.36	0.43	156.30	6.80	1930.200	9.800	3580.0	2550.0	15.60	8277.1	29.6	0.30	0.33	51.008
S87	S1-12					2.7400	0.1600	0.2240	0.0270	119.54	0.87	106.32	0.99	336.10	7.70	611.000	154.000	1640.0	105.0	13.60	17390.5	2572.9	0.17	0.02
S89						1.0810	0.0550	0.6390	0.0380	87.61	0.16	238.99	0.18	126.40	4.00	1783.000	26.000	406.0	27.0	15.30	3191.8	407.2	0.46	0.04
S91						1.9170	0.0890	0.3030	0.0340	114.49	0.32	105.35	0.74	356.40	1.60	1108.000	69.000	958.0	50.0	12.20	10928.4	74.5	0.22	0.02
S96	S0-96	GCIRS 16C	Ofpe/WN9			1.4990	0.0570	0.1740	0.0220	126.36	0.96	115.66	0.59	233.60	2.40	1646.000	16.000	662.0	29.0	10.00	10127.0	530.0	0.22	0.02
S97 A	S1-16	GCIRS 16SW	Ofpe/WN9	50	24,400	2.3200	0.4600	0.3500	0.1100	113.00	1.30	113.20	1.40	28.00	14.00	2132.000	29.000	1270.0	309.0	10.30	12333.9	305.9	0.21	0.08	54.5 × 58.2 × 62.7
S97 B	S1-16	GCIRS 16SW	Ofpe/WN9	50	23,500	2.3200	0.4600	0.3500	0.1100	113.00	1.30	113.20	1.40	28.00	14.00	2132.000	29.000	1270.0	309.0	10.30	12333.9	305.9	0.21	0.08	54.5 × 58.2 × 62.7
S145			M III	5.1216	3,330	1.1200	0.1800	0.5000	0.2500	83.70	1.60	263.92	0.94	185.00	16.00	1808.000	58.000	426.0	71.0	17.50	4580.2	1471.2	0.37	0.10	179.46
S175						0.4140	0.0390	0.9867	0.0018	88.53	0.60	326.83	0.78	68.52	0.40	2009.510	0.010	96.2	5.0	17.50	45.0	0.8	4.27	0.47
S4711			B8-9 V	2.2	11,587.84	0.0751	0.0015	0.768	0.030	114.71	2.92	20.10	3.72	131.59	3.09	2010.85	0.06	7.6	0.3	18.4	143.7	7.4	2.2	0.2	2.59
S4712			B9-A0 V	2.2	10,000	0.451	0.0025	0.365	0.032	117.28	1.31	166.38	3.20	238.08	3.43	2007.12	0.08	112.0	2.9	18.4	2366	120	0.48	0.02
S4713				2.1		0.2	0.095	0.351	0.059	111.07	1.66	95.06	5.15	301.97	8.02	2000.03	0.22	33.2	2.5	18.5	1073	110	0.71	0.05
S4714				2		0.102	0.0003	0.985	0.011	127.7	0.28	129.28	0.63	357.25	0.08	2017.29	0.02	12.0	0.3	17.7	12.6	9.3	8.0	3
S4715			B9 V	2.8		0.1439	0.011	0.247	0.040	129.8	3.72	282.15	2.92	359.99	5.38	2008.05	0.3	20.2	2.4	17.8	894	83	0.75	0.04	2.37
S4716			B7-8 V		12,417.07	1.9300		0.756		161.24		151.54		0.073				4.0							2.45
R34						1.8100	0.1500	0.6410	0.0980	136.00	8.30	330.00	19.00	57.00	8.00	1522.000	52.000	877.0	83.0	14.00	5314.6	856.3	0.36	0.05
R44						3.9000	1.4000	0.2700	0.2700	131.00	5.20	80.50	7.10	217.00	24.00	1963.000	85.000	2730.0	1350.0	14.00	23285.6	901.5	0.15	0.11
id1	id2					a	Δa	e	Δe	i (°)	Δi	Ω (°)	ΔΩ	ω (°)	Δω	Tp (yr)	ΔTp	P (yr)	ΔP	Kmag	q (AU)	Δq	v (%c)	Δv

References

Eisenhauer, F.; et al. (July 20, 2005). "SINFONI in the Galactic Center: Young Stars and Infrared Flares in the Central Light-Month". The Astrophysical Journal. 628 (1): 246–259. arXiv:astro-ph/0502129. Bibcode:2005ApJ...628..246E. doi:10.1086/430667. S2CID 122485461.
^ Peißker, Florian; Eckart, Andreas; Zajaček, Michal; Basel, Ali; Parsa, Marzieh (August 2020). "S62 and S4711: Indications of a Population of Faint Fast-moving Stars inside the S2 Orbit—S4711 on a 7.6 yr Orbit around Sgr A*". The Astrophysical Journal. 889 (50): 5. arXiv:2008.04764. Bibcode:2020ApJ...899...50P. doi:10.3847/1538-4357/ab9c1c. S2CID 221095771.
Gillessen, S.; et al. (February 2017). "An Update on Monitoring Stellar Orbits in the Galactic Center". The Astrophysical Journal. 837 (1): 30. arXiv:1611.09144. Bibcode:2017ApJ...837...30G. doi:10.3847/1538-4357/aa5c41. S2CID 119087402.
Abuter, R.; Amorim, A.; Bauböck, M.; Berger, J. P.; Bonnet, H.; Brandner, W.; Clénet, Y.; Coudé Du Foresto, V.; De Zeeuw, P. T.; Dexter, J.; Duvert, G.; Eckart, A.; Eisenhauer, F.; Förster Schreiber, N. M.; Garcia, P.; Gao, F.; Gendron, E.; Genzel, R.; Gerhard, O.; Gillessen, S.; Habibi, M.; Haubois, X.; Henning, T.; Hippler, S.; Horrobin, M.; Jiménez-Rosales, A.; Jocou, L.; Kervella, P.; Lacour, S.; et al. (April 2019). "A geometric distance measurement to the Galactic center black hole with 0.3% uncertainty". Astronomy & Astrophysics. 625: L10. arXiv:1904.05721. Bibcode:2019A&A...625L..10G. doi:10.1051/0004-6361/201935656. S2CID 119190574.
Peißker, Florian; Eckart, Andreas; Parsa, Marzieh (January 2020). "S62 on a 9.9 year orbit around SgrA*". The Astrophysical Journal. 889 (1): 61. arXiv:2002.02341. Bibcode:2020ApJ...889...61P. doi:10.3847/1538-4357/ab5afd. S2CID 211043784.
Næss, S. (October 4, 2019). "Galactic center S-star orbital parameters".

Constellation of Sagittarius

Stars

Bayer	α (Rukbat) β (Arkab Prior) β (Arkab Posterior) γ (W) γ (Alnasl) δ (Kaus Media) ε (Kaus Australis) ζ (Ascella) η θ θ ι κ κ λ (Kaus Borealis) μ (Polis) ν (Ainalrami) ν ξ ξ ο π (Albaldah) ρ ρ σ (Nunki) τ υ φ χ χ χ ψ ω (Terebellum)
Flamsteed	1 4 5 6 7 9 12 14 15 16 17 18 21 23 24 25 26 28 29 30 31 33 43 (d) 50 51 (h) 52 (h) 53 54 (e) 55 (e) 56 (f) 57 59 (b) 60 (A) 61 (g) 62 (c) 63 65 63 Oph
Variable	T U X (3) Y RR RS RY RZ VX VY VZ WZ XX XZ YY YZ AQ AS AV BB FN GM GU KW MV V348 V350 V356 V440 V505 V523 V526 V617 V630 V725 V732 V774 V919 V1017 V1059 V1216 V1223 V1647 V1942 V3792 V3795 V3804 V3879 V3885 V3890 V3892 V3894 V3903 (11) V3961 V3984 V4021 V4024 V4028 V4029 V4030 V4046 V4050 V4064 V4072 V4089 V4091 V4138 V4140 V4160 V4169 V4190 V4198 V4199 V4200 V4332 V4333 V4334 V4371 V4375 V4381 V4387 V4405 V4407 V4434 V4444 V4580 V4633 V4641 V4647 (Pistol Star) V4650 V4728 V4743 V4745 V4998 V5112 V5115 V5116 V5125 V5157 V5555 V5558 V5652 V5668 V5856
HR	6617 6679 6680 6691 6692 6693 6704 6716 6739 6748 6762 6766 6769 6777 6780 6788 6798 6835 6836 6838 6842 6864 6874 6889 6907 6909 6914 6919 6933 6936 6944 6960 6972 6988 6990 6998 7026 7029 7035 7038 7072 7104 7126 7128 7151 7159 7164 7166 7168 7182 7186 7195 7203 7205 7211 7230 7239 7240 7246 7265 7276 7277 7282 7316 7317 7327 7330 7334 7350 7355 7360 7367 7378 7380 7392 7398 7410 7433 7443 7454 7473 7491 7496 7507 7532 7538 7585 7616 7627 7629 7630 7631 7639 7643 7652 7658 7659 7703 7706 7725 7765 7799 7801 7808
HD	163296 163758 164604 (Pincoya) 164816 165052 166191 169142 170657 171238 175390 175754 177765 180902 181342 181720 183577 187085 187150 190647 313846 316285
Other	2MASS 19281982-2640123 2MASS J18352154–3123385 2MASS J19513587-3510375 4U 1755-33 4U 1820-30 A1742-294 Ap 1-11 AS 295 BD -18 5550 Bursting Pulsar CWISEP J1935-1546 GCIRS 13E 745 GGD 27 GRO J1744−28 GRS 1758-258 GS 1826-24 GX 3-1 GX 5-1 GX 9-1 GX 13+1 HATS-36 Herschel 36 HETE J1900.1-2455 IRAS 17423-1755 IRAS 18162−2048 GCIRS 3 GCIRS 7 GCIRS 8* GCIRS 16SW Gomez's Hamburger G0.238-0.071 K2-2016-BLG-0005L LBV 1806-20 LS IV -12 111 MACHO 176.18833.411 MACHO-1997-BLG-41 MACHO-98-BLG-35 NGC 6822-WR 12 PSR B1744−24A PSR B1749−28 PSR B1757−24 PSR B1758−23 PSR B1800−21 PSR B1821−24 PSR B1857−26 PSR J1808−2024 PSR J1747−2958 PSR J1748−2446ad S2 S55 S62 S4716 SAX J1747.0−2853 SAX J1808.4−3658 SAX J1810.8−2609 SWEEPS J175853.92−291120.6 SWEEPS J175902.00-291323.7 SWEEPS J175902.67−291153.5 Swift J1745-26 SWIFT J1756.9−2508 Th 4-4 W33A WASP-67 WD 0032−317 WR 102 c ea ka WR 101-2 WR 104 WR 110 WR 111 WR 112 XTE J1748−288 XTE J1807−294 XTE J1810−197 XTE J1814−338

Exoplanets	HATS-36b HD 164604 b HD 181720 b K2-2016-BLG-0005Lb KMT-2022-BLG-0440L b MOA-2007-BLG-192Lb MOA-2007-BLG-400Lb MOA-2009-BLG-387Lb MOA-2010-BLG-477Lb OGLE-2003-BLG-235Lb OGLE-2005-BLG-169Lb OGLE-2018-BLG-1119Lb OGLE-TR-10b OGLE-TR-56b SWIFT J1756.9-2508 b

Star
clusters

NGC	NGC 6440 NGC 6520 NGC 6522 NGC 6528 NGC 6530 NGC 6540 NGC 6544 NGC 6553 NGC 6558 NGC 6569 NGC 6603 NGC 6624 NGC 6638 NGC 6642 NGC 6717 NGC 6723
Other	1806−20 cluster 2MASS-GC02 Arches Cluster CO-0.40-0.22 Messier 18 Messier 21 Messier 22 Messier 23 Messier 25 Messier 28 Messier 54 Messier 55 Messier 69 Messier 70 Messier 75 Quintuplet cluster Small Sagittarius Star Cloud

Nebulae

NGC	NGC 6822 (Bubble Nebula) NGC 6445 NGC 6559 NGC 6563 NGC 6565 NGC 6578 NGC 6589 NGC 6590 NGC 6818
Other	Barnard 92 G1.9+0.3 HCN-0.009-0.044 Lagoon Nebula Large Molecule Heimat M 1-42 M2-42 Omega Nebula Pistol Nebula Red Spider Nebula Ring Nebula Trifid Nebula

Galaxies

NGC	NGC 6822 NGC 6902
Other	MRC 2011-298 PKS 1830-211 PKS 2000-330 PKS 2004-447 Sagittarius Dwarf Irregular Galaxy Sagittarius Dwarf Spheroidal Galaxy

Galaxy clusters	ESO 593-8

Astronomical events	GLEAM-X J162759.5−523504.3 MOA-2007-BLG-192L MOA-2007-BLG-400L MOA-2009-BLG-387L MOA-2010-BLG-477L MOA-2011-BLG-262L OGLE-2003-BLG-235L OGLE-2005-BLG-169L Nova Sagittarii 1982