The 800 pc long tidal tails of the Hyades star cluster

Jeřabková, Tereza; Boffin, H. M. J.; Beccari, G.; Marchi, Guido De; Bruijne, J. H. J. de; Prusti, T.

doi:10.1051/0004-6361/202039949

Cited by 69 publications

(107 citation statements)

References 93 publications

(136 reference statements)

Supporting

Mentioning

102

Contrasting

Order By: Relevance

“…Gas expulsion not only unbinds many stars from the clusters, but also decreases their density so that many of the youngest clusters cannot be detected, an idea originally proposed by Lüghausen et al (2012). The overestimate of f IC,pop in older clusters can be caused by neglecting the interaction of clusters with molecular clouds in our models, which probably plays an important role in cluster dissolution (Terlevich 1987;Lamers & Gieles 2006;Chandar et al 2010;Jerabkova et al 2021).…”

Section: Comparison To Observations and To The Current Theoretical Modelmentioning

confidence: 86%

Do the majority of stars form as gravitationally unbound?

Dinnbier,

Kroupa,

Anderson

2022

Preprint

View full text Add to dashboard Cite

Context. Some of the youngest stars (age 10 Myr) are clustered, while many others are observed scattered throughout star forming regions or in complete isolation. It has been intensively debated whether the scattered or isolated stars originate in star clusters, or if they form truly isolated, which could help constrain the possibilities how massive stars are formed. Aims. We adopt the assumption that all stars form in gravitationally bound star clusters embedded in molecular cloud cores (Γ-1 model), which expel their natal gas early after their formation, and compare the fraction of stars found in clusters with observational data. Methods. The star clusters are modelled by the code nbody6, which includes binary stars, stellar and circumbinary evolution, gas expulsion, and the external gravitational field of their host galaxy. Results. We find that small changes in the assumptions in the current theoretical model estimating the fraction, Γ, of stars forming in embedded clusters have a large influence on the results, and we present a counterexample as an illustration. This calls into question theoretical arguments about Γ in embedded clusters, and it suggests that there is no firm theoretical ground for low Γ in galaxies with lower star formation rates (SFRs). Instead, the assumption that all stars form in embedded clusters is in agreement with observational data for the youngest stars (age 10 Myr). In the Γ-1 scenario, the observed fraction of the youngest stars in clusters increases with the SFR only weakly; the increase is caused by the presence of more massive clusters in galaxies with higher SFRs, which release fewer stars to the field in proportion to their mass. The Γ-1 model yields a higher fraction of stars in clusters for older stars (age between 10 Myr and 300 Myr) than what is observed. This discrepancy can be caused by initially less compact clusters and/or a slightly lower star formation efficiency than originally assumed in the Γ-1 model, or by interactions of the post gas expulsion revirialised open clusters with molecular clouds.

show abstract

Section: Comparison To Observations and To The Current Theoretical Modelmentioning

confidence: 86%

Do the majority of stars form as gravitationally unbound?

Dinnbier,

Kroupa,

Anderson

2022

Preprint

View full text Add to dashboard Cite

show abstract

“…Giant molecular clouds passing through a tidal tail can stir asymmetry in the tail (Jerabkova et al 2021), which was indicated in the tail (in this case tail II) of the Hyades (Röser et al 2019). According to the results of Jerabkova et al (2021), giant molecular clouds might distort also tidal tail I so that its tilt β would no longer be a clear function of the age of the cluster or stream.…”

Section: Comparison To Stellar Evolutionary Age Estimatesmentioning

confidence: 94%

Estimating the ages of open star clusters from properties of their extended tidal tails

Dinnbier,

Kroupa,

Šubr

et al. 2021

Preprint

View full text Add to dashboard Cite

The most accurate current methods for determining the ages of open star clusters, stellar associations and stellar streams are based on isochrone fitting or the lithium depletion boundary. We propose another method for dating these objects based on the morphology of their extended tidal tails, which have been recently discovered around several open star clusters. Assuming that the early-appearing tidal tails, the so called tidal tails I, originate from the stars released from the cluster during early gas expulsion, or that they form in the same star forming region as the cluster (i.e. being coeval with the cluster), we derive the analytical formula for the tilt angle β between the long axis of the tidal tail and the orbital direction for clusters or streams on circular trajectories. Since at a given Galactocentric radius, β is only a function of age t regardless of the initial properties of the cluster, we estimate the cluster age by inverting the analytical formula β = β(t). We illustrate the method on a sample of 12 objects, which we compiled from the literature, and we find a reasonable agreement with previous dating methods in ≈ 70% of the cases. This can probably be improved by taking into account the eccentricity of the orbits and by revisiting the dating methods based on stellar evolution. The proposed morphological method is suitable for relatively young clusters (age 300 Myr), where it provides a relative age error of the order of 10 to 20% for an error in the observed tilt angle of 5 • .

show abstract

“…The combination of the striking precision of the Gaia astrometric measurements and its all sky coverage allowed the detection of prominent structures around some OCs by several groups. , Meingast & Alves (2019) and Jerabkova et al (2021) characterized the tidal tails of the Hyades at large spatial scale with different methods. The tidal tails of Coma Berenices, Ruprecht 147, Praesepe, Blanco 1, NGC 2506 and NGC 752 were discovered successively by Tang et al (2019), Yeh et al (2019), , Zhang et al (2020), Gao (2020) and Bhattacharya et al (2021).…”

Section: Introductionmentioning

confidence: 99%

Structural parameters of 389 local Open Clusters

Tarricq,

Soubiran,

Casamiquela

et al. 2021

Preprint

View full text Add to dashboard Cite

Context. The distribution of member stars in the surroundings of an open cluster can shed light on the process of its formation, evolution and dissolution. The analysis of structural parameters of open clusters as a function of their age and position in the Galaxy brings constraints on theoretical models of cluster evolution. The Gaia catalogue is very appropriate to find members of open clusters at large distance from their centers. Aims. We aim at revisiting the membership lists of open clusters from the solar vicinity, in particular by extending these membership lists to the peripheral areas thanks to Gaia EDR3. We then take advantage of these new lists of members to study the morphological properties and the mass segregation levels of the clusters. Methods. We used the clustering algorithm HDBSCAN on Gaia parallaxes and proper motions to systematically look for members up to 50 pc from the cluster centers. We fitted a King's function on the radial density profile of these clusters and a Gaussian Mixture Model on their two dimensional distribution of members to study their shape. We also evaluated the degree of mass segregation of the clusters and the correlations of these parameters with the age and Galactic position of the clusters. Results. Our methodology performs well on 389 clusters out of the 467 selected ones, including several recently discovered clusters that were poorly studied until now. We report the detection of vast coronae around almost all the clusters and report the detection of 71 open clusters with tidal tails, multiplying by more than four the number of such structures identified. We find the size of the cores to be on average smaller for old clusters than for young ones. Also, the overall size of the clusters seems to slightly increase with age while the fraction of stars in the halo seems to decrease. As expected the mass segregation is more pronounced in the oldest clusters but a clear trend with age is not seen. Conclusions. Open Clusters are more extended than previously expected, regardless of their age. The decrease in the proportion of stars populating the clusters halos highlights the different cluster evaporation processes and the short timescales they need to affect the clusters. Reported parameters like cluster sizes or mass segregation levels all depend on cluster ages but can not be described as single functions of time.

show abstract

The 800 pc long tidal tails of the Hyades star cluster

Cited by 69 publications

References 93 publications

Do the majority of stars form as gravitationally unbound?

Do the majority of stars form as gravitationally unbound?

Estimating the ages of open star clusters from properties of their extended tidal tails

Structural parameters of 389 local Open Clusters

Contact Info

Product

Resources

About