J/A+A/638/A9 A census of the near-by Psc-Eri stellar stream (Roeser+, 2020)
A census of the near-by Pisces-Eridanus stellar stream.
Commonalities with and disparities from the Pleiades.
Roeser S., Schilbach E.
<Astron. Astrophys. 638, A9 (2020)>
=2020A&A...638A...9R 2020A&A...638A...9R (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Populations, stellar ; Magnitudes ; Stars, masses
Keywords: globular clusters: individual: Pisces-Eridanus stream -
stars: evolution - stars: luminosity function, mass function -
Hertzsprung-Russell and C-M diagrams -
open clusters and associations: individual: M45 (Pleiades)
Abstract:
Within a sphere of 400pc radius around the Sun, we search for members
of the Pisces-Eridanus (Psc-Eri) stellar stream in the Gaia Data
Release 2 DR2) data set. We compare basic astrophysical
characteristics of the stream with those of the Pleiades. We used a
modified convergent-point method to identify stars with 2D -
velocities consistent with the space velocity of the Psc-Eri stream
and the Pleiades, respectively. We found 1387 members of the Psc-Eri
stream in a G-magnitude range from 5.1mag to 19.3mag at distances
between 80 and 380pc from the Sun. The stream has a nearly cylindrical
shape with a length of at least 700pc and a thickness of 100pc. The
accumulated stellar mass of the 1387 members amounts to about
770M☉, and the stream is gravitationally unbound. For the stream
we found an age of about 135Myr. In many astrophysical properties
Psc-Eri is comparable to the open cluster M45 (the Pleiades): in its
age, its luminosity function (LF), its present-day mass function
(PDMF) as well as in its total mass. Nonetheless, the two stellar
ensembles are completely unlike in their physical appearance. We
cautiously give two possible explanations for this disagreement: (i)
the star-formation efficiency in their parental molecular clouds was
higher for the Pleiades than for Psc-Eri or/and (ii) the Pleiades had
a higher primordial mass segregation immediately after the expulsion
of the molecular gas of the parental cloud.
Description:
We used a modified 5D convergent-point approach to search for hitherto
unrevealed members of the Psc-Eri stellar stream detected by Meingast
et al. (2019A&A...622L..13M 2019A&A...622L..13M. Cat. J/A+A/622/L13). Based on Gaia DR2,
we found 1387 co-moving members in a G magnitude range from 5.1mag to
G=19.3mag.
All parameters based on or derived from Gaia DR2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 112 1387 Psc-Eri stream members
tablea2.dat 112 1245 Pleiades members
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/622/L13 : Stellar stream in Gaia DR2 discovery (Meingast+, 2019)
Byte-by-byte Description of file: tablea1.dat tablea2.dat
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Bytes Format Units Label Explanations
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3- 21 I19 --- Source Gaia DR2 source id (source_id)
23- 32 F10.5 deg RAdeg Gaia DR2 right ascension (ICRS at Ep=2015.5)
rounded to 10-5 degrees
34- 43 F10.5 deg DEdeg Gaia DR2 declination (ICRS at Ep=2015.5)
rounded to 10-5 degrees
45- 51 F7.3 mag Gmag G-band mean magnitude (Vega) (photgmean_mag)
54- 60 F7.2 pc X Galactic Cartesian coordinate X
(positive towards the Galactic centre)
62- 68 F7.2 pc Y Galactic Cartesian coordinate Y (positive in
the direction of Galactic rotation)
70- 76 F7.2 pc Z Galactic Cartesian coordinate Z
(positive towards the North Galactic Pole)
78- 83 F6.2 km/s dvpar Velocity parallel to the convergent point (1)
85- 90 F6.2 km/s vpero Velocity perpendicular to the convergent
point (2)
92- 99 F8.2 --- pcont Probability of being contaminated (3)
101-106 F6.2 Msun Mass Mass of the star (system mass; see paper)
108-112 E5.2 --- RUWE The value of RUWE as given in Gaia DR2
(see paper)
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Note (1): dvpar is the difference between the observed velocity and the
predicted velocity parallel to the convergent point in the tangential plane
(see paper).
Note (2): vpero is the observed velocity perpendicular to the convergent point
in the tangential plane (see paper).
Note (3): pconta is the probability that the star belongs to the background
population. The value of ln(pconta) is given (see paper).
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Acknowledgements:
Siegfried Roeser, roeser(at)ari.uni-heidelberg.de
(End) Siegfried Roeser [Heidelberg], Patricia Vannier [CDS] 14-Apr-2020