2018A&A...617A..56S


Query : 2018A&A...617A..56S

2018A&A...617A..56S - Astronomy and Astrophysics, volume 617A, 56-56 (2018/9-1)

A CEMP-no star in the ultra-faint dwarf galaxy Pisces II.

SPITE M., SPITE F., FRANCOIS P., BONIFACIO P., CAFFAU E. and SALVADORI S.

Abstract (from CDS):


Aims. A probable carbon enhanced metal-poor (CEMP) star, PiscesII 10694, was discovered recently in the ultra-faint (UFD) galaxy PiscesII. This galaxy is supposed to be very old, suspected to include dark matter, and likely formed the bulk of its stars before the reionisation of the Universe.
Methods. New abundances have been obtained from observations of PiscesII 10694 at the Kueyen ESO VLT telescope, using the high-efficiency spectrograph: X-shooter.
Results. We found that PiscesII 10694 is a CEMP-no star with [Fe/H]=-2.60dex. Careful measurements of the CH and C2 bands confirm the enhancement of the C abundance ([C/Fe]=+1.23). This cool giant has very probably undergone extra mixing and thus its original C abundance could be even higher. Nitrogen, O, Na, and Mg are also strongly enhanced, but from Ca to Ni the ratios [X/Fe] are similar to those observed in classical very metal-poor stars. With its low Ba abundance ([Ba/Fe]=-1.10dex) PiscesII 10694 is a CEMP-no star. No variation in the radial velocity could be detected between 2015 and 2017. The pattern of the elements has a shape similar to the pattern found in galactic CEMP-no stars like CS 22949-037 ([Fe/H]=-4.0) or SDSS J1349+1407 ([Fe/H]=-3.6).
Conclusions. The existence of a CEMP-no star in the UFD galaxy PiscII suggests that this small galaxy likely hosted zero-metallicity stars. This is consistent with theoretical predictions of cosmological models supporting the idea that UFD galaxies are the living fossils of the first star-forming systems.

Abstract Copyright: © ESO 2018

Journal keyword(s): stars: abundances - Local Group - galaxies: dwarf - galaxies: abundances

Simbad objects: 16

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Number of rows : 16
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 [CSF2018] 11-1-4422 Pe* 00 59 36.6225678984 -33 40 38.452788624           ~ 3 0
2 NAME Sculptor Dwarf Galaxy G 01 00 09.4 -33 42 32   9.79 8.6 8.81   ~ 1265 4
3 BPS CS 31082-0001 Pe* 01 29 31.1311443552 -16 00 45.495314460 12.527 12.427 11.642 11.189 10.713 CEMP 275 0
4 NAME Segue 1 G 10 07 03.2 +16 04 25     15.3     ~ 414 1
5 2MASS J10081444+1605011 Pe* 10 08 14.4415595736 +16 05 01.198034340           ~ 23 1
6 HE 1327-2326 Pe* 13 30 05.9394958608 -23 41 49.699340844 13.761 14.01 13.55 13.50 12.803 CEMP-no 229 0
7 2MASS J13492290+1407369 * 13 49 22.9157929224 +14 07 37.006663008           ~ 9 0
8 NAME Bootes Dwarf Spheroidal Galaxy G 14 00 00.0 +14 30 00     12.8     ~ 397 0
9 2MASS J14000985+1428228 * 14 00 09.8519784912 +14 28 22.997618256           ~ 12 0
10 HD 122563 Pe* 14 02 31.8455084952 +09 41 09.944391876 7.47 7.10 6.19 5.37 4.79 G8:III:Fe-5 808 0
11 BPS CS 22892-0052 Pe* 22 17 01.6558764360 -16 39 27.051026544   14.03 13.20 13.06 12.19 KIIvw 433 0
12 NAME Tuc II G 22 51 55.1 -58 34 08           ~ 113 0
13 [SSW2012] Pisces II 10694 * 22 58 25.0754200608 +05 57 20.109688668           ~ 6 0
14 NAME Pisces II G 22 58 31.0 +05 57 09     16.3     ~ 235 0
15 HE 2323-0256 Pe* 23 26 29.8073738880 -02 39 58.036383180   15.12 14.36   13.358 CEMP-no 175 0
16 NAME Local Group GrG ~ ~           ~ 7849 0

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2022.12.09-21:24:43

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