2020MNRAS.491.2465K


Query : 2020MNRAS.491.2465K

2020MNRAS.491.2465K - Mon. Not. R. Astron. Soc., 491, 2465-2480 (2020/January-2)

Discovery of a nearby 1700 km s-1 star ejected from the Milky Way by Sgr A*.

KOPOSOV S.E., BOUBERT D., LI T.S., ERKAL D., DA COSTA G.S., ZUCKER D.B., JI A.P., KUEHN K., LEWIS G.F., MACKEY D., SIMPSON J.D., SHIPP N., WAN Z., BELOKUROV V., BLAND-HAWTHORN J., MARTELL S.L., NORDLANDER T., PACE A.B., DE SILVA G.M., WANG M.-Y. (The S5 Collaboration)

Abstract (from CDS):

We present the serendipitous discovery of the fastest main-sequence hyper-velocity star (HVS) by the Southern Stellar Stream Spectroscopic Survey (S5). The star S5-HVS1 is a ∼2.35 M☉ A-type star located at a distance of ∼9 kpc from the Sun and has a heliocentric radial velocity of 1017 ± 2.7 km s^{-1} without any signature of velocity variability. The current 3D velocity of the star in the Galactic frame is 1755 ± 50 km s^{-1}. When integrated backwards in time, the orbit of the star points unambiguously to the Galactic Centre, implying that S5-HVS1 was kicked away from Sgr A* with a velocity of ∼1800 km s^{-1} and travelled for 4.8 Myr to its current location. This is so far the only HVS confidently associated with the Galactic Centre. S5-HVS1 is also the first hyper-velocity star to provide constraints on the geometry and kinematics of the Galaxy, such as the Solar motion Vy,☉ = 246.1 ± 5.3 km s^{-1} or position R0 = 8.12 ± 0.23 kpc. The ejection trajectory and transit time of S5-HVS1 coincide with the orbital plane and age of the annular disc of young stars at the Galactic Centre, and thus may be linked to its formation. With the S5-HVS1 ejection velocity being almost twice the velocity of other hyper-velocity stars previously associated with the Galactic Centre, we question whether they have been generated by the same mechanism or whether the ejection velocity distribution has been constant over time.

Abstract Copyright: © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): stars: kinematics and dynamics - Galaxy: centre - Galaxy: fundamental parameters

Simbad objects: 23

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Number of rows : 23
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 M 31 AGN 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 12678 1
2 UCAC2 1342515 sg? 01 02 01.0044431640 -71 22 20.831166984   14.76 13.63 13.48 12.56 ~ 8 0
3 LAMOST-HVS3 HV* 03 21 17.0742443232 +19 07 36.229223964   16.63 16.69     B7V 4 0
4 HE 0437-5439 HS* 04 38 12.7828168224 -54 33 11.834984736 15.37 16.18 16.42     sdB+F 77 0
5 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 17478 0
6 HD 271791 HV* 06 02 27.8785167216 -66 47 28.695328404   12.17 12.28     B2(III) 69 0
7 LAMOST-HVS1 Em* 09 12 06.5238309096 +09 16 21.890911908   12.96 13.06     B1IV/V 19 0
8 [BGK2006] HV 4 HS* 09 13 01.0031830944 +30 51 19.878673752   18.1 18.5     sdB/sdO 21 0
9 [BGK2006] HV 5 HV* 09 17 59.4745317960 +67 22 38.377645896     17.70     B 20 0
10 US 708 HS* 09 33 20.8631859264 +44 17 05.495440452   18.5 18.8     sdOHe 94 0
11 [BGK2006] HV 6 HV* 11 05 57.4506801480 +09 34 39.493679160     19.11     B 16 0
12 2QZ J111136.4+005855 HV* 11 11 36.4436777976 +00 58 56.430744600           B 7 0
13 SDSS J113312.12+010824.8 HS* 11 33 12.1225194672 +01 08 24.841717008   17.2 17.80 17.7   sdB 31 0
14 SDSS J113637.13+033106.8 HV* 11 36 37.1370991368 +03 31 06.933976356           B 6 0
15 [BGK2006] HV 10 HV* 12 03 37.8548727096 +18 02 50.385104700     19.36     B 14 0
16 PG 1618+379 HB* 16 20 20.7665215056 +37 47 39.989826492   14.98 15.10     B2V 14 0
17 NAME Fermi Bubbles bub 17 45 -29.0           ~ 440 0
18 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 14463 0
19 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 4400 3
20 NAME SDG G 18 55 19.0 -30 32 43   4.5 3.6     ~ 2195 2
21 HE 2251-5127 HV* 22 54 51.6245437488 -51 11 44.195809848   16.0 16.1     ~ 33 0
22 LAMOST-HVS4 HV* 22 58 37.5583345464 +40 00 05.413913136           ~ 6 0
23 NAME Local Group GrG ~ ~           ~ 8415 0

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