1997A&A...318..805M


Query : 1997A&A...318..805M

1997A&A...318..805M - Astronomy and Astrophysics, volume 318, 805-811 (1997/2-3)

Hα emission fluxes and lithium abundances of low-mass stars in the young open cluster IC 4665.

MARTIN E.L. and MONTES D.

Abstract (from CDS):

As part of a long term effort to understand pre-main sequence Li burning, we have obtained high resolution spectroscopic observations of 14 late type stars (G0-M1) in the young open cluster IC 4665. Most of the stars have Hα filled-in and LiI absorption, as expected for their young age. From the equivalent widths of Hα emission excess (obtained using the spectral subtraction technique) and the LiIλ6708 feature, we have derived Hα emission fluxes and photospheric Li abundances. The mean Li abundance of IC 4665 solar-type stars is log N(Li)=3.1; the same as in other young clusters (α Per, Pleiades) and T Tauri stars. Our results support the conclusions from previous works that PMS Li depletion is very small for masses ∼1M . Among the IC 4665 late-G and early K-type stars, there is a spread in Li abundances of about one order of magnitude. The Li-poor IC 4665 members have low Hα excess and vsini≤10. Hence, the Li-activity-rotation connection which has been clearly established in the Pleiades also seems to hold in IC 4665. One M-type IC 4665 star that we have observed does not show Li, implying a very efficient Li depletion as observed in α Per stars of the same spectral type. The level of chromospheric activity and Li depletion among the low-mass stars of IC 4665 is similar to that in the Pleiades. In fact, we note that the Li abundance distributions in several young clusters (α Per, Pleiades, IC 2391, IC 4665) and in post T Tauri stars are strikingly similar. This result suggests that Hα emission and Li abundance not well correlated with age for low-mass stars between 20 and 100 Myr old. We argue that a finer age indicator, the ``LL-clock", would be the luminosity at which the transition between efficient Li depletion and preservation takes place for fully convective objects. The LL-clock could allow in the near future to derive the relative ages of young open clusters, and clarify the study of PMS evolution of cool stars.

Abstract Copyright:

Journal keyword(s): stars: abundances, activity, pre-main sequence - clusters: open: individual: IC 4665

Simbad objects: 31

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Number of rows : 31
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 V* V601 Per BY* 03 23 03.3712155792 +48 53 05.793588024     21.21     M6 20 0
2 Cl Melotte 20 OpC 03 26 28 +48 58.5           ~ 795 0
3 Cl Melotte 22 OpC 03 46 24 +24 06.8           ~ 3183 0
4 Cl* Melotte 22 PPL 15 LM* 03 48 04.6585327824 +23 39 30.318163560         17.91 M6.5 99 0
5 CD-52 2472 SB* 08 38 55.6626968784 -52 57 51.679265796 11.19 11.01 10.33 10.19   G2 35 0
6 V* V364 Vel BY* 08 39 53.0493554064 -52 57 56.847553812   12.75 11.89 11.69   K0 33 0
7 IC 2391 OpC 08 41 10 -52 59.5           ~ 766 0
8 V* V366 Vel BY* 08 41 25.8875436000 -53 22 41.467632456   13.63 12.519   11.277 K3e 30 0
9 V* V367 Vel BY* 08 41 39.6670054632 -52 59 34.032238440   14.63 12.613     K7.5e 20 0
10 Cl* IC 2391 SHJM 7 SB* 08 41 52.1694642216 -53 06 46.668430332   13.62 12.52     G7 12 1
11 V* V368 Vel BY* 08 41 57.8482531848 -52 52 13.942332264   14.59 13.76 12.74 12.03 K7e 29 0
12 V* V371 Vel BY* 08 42 18.5563649256 -53 01 56.872692444   15.44       M2e 28 0
13 CPD-52 1614 SB* 08 42 46.6075101288 -53 01 01.341693984   10.7 10.3     ~ 30 0
14 V* V373 Vel BY* 08 43 27.7498717776 -52 57 39.097540332       14.12   ~ 20 0
15 V* V372 Vel BY* 08 43 27.8600657448 -52 57 35.900992260       13.51   ~ 18 0
16 2MASS J17445810+0551329 Y*O 17 44 58.1022677952 +05 51 32.868902340   14.31 13.426   12.623 G7 25 0
17 V* V2316 Oph BY* 17 45 19.3988522256 +05 47 40.119087444   14.60 13.716   12.696 G6 27 0
18 V* V2317 Oph BY* 17 45 19.6432303320 +05 36 54.755808408   13.49 12.729   11.711 G0 16 0
19 V* V2318 Oph BY* 17 45 25.0724676024 +05 51 38.870504064   14.39 13.716   12.697 G5 27 0
20 Cl* IC 4665 P 94 * 17 45 53.0949964392 +05 36 29.204755884   14.27 14.243   13.149 G8 20 0
21 V* V2319 Oph BY* 17 45 56.7967605336 +05 22 33.440795652   13.42 12.620   11.682 G0 16 0
22 V* V2321 Oph BY* 17 46 11.9798853168 +05 41 25.876171068   15.43 14.407   13.074 K0 24 0
23 IC 4665 OpC 17 46 13 +05 36.9           ~ 337 0
24 2MASS J17461900+0546203 Y*O 17 46 18.9987185040 +05 46 20.433832140   18.42 16.910   14.745 M1 10 0
25 Cl* IC 4665 P 107 * 17 46 24.7223108568 +05 17 21.379412328   13.78 12.921   11.870 G1 23 0
26 Cl* IC 4665 P 146 * 17 47 30.0358417488 +05 31 36.517254996   15.31 14.204   12.986 K0 8 0
27 V* V2325 Oph BY* 17 47 33.3157647552 +05 31 46.026952428   13.94 13.126   12.107 G4 27 0
28 V* V2326 Oph BY* 17 47 44.0281203696 +05 21 59.234653512   14.43       G5 19 0
29 2MASS J17480497+0548421 Y*? 17 48 04.9838214336 +05 48 41.921508456   14.30 13.528   12.364 G9 20 0
30 Cl* IC 4665 P 166 * 17 48 06.6455088480 +05 48 33.897657348   14.76 13.838   12.603 K0 10 0
31 V* EK Cep EB* 21 41 21.5042268336 +69 41 34.112933916   7.95 7.89     A0V 206 0

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2022.05.22-21:34:19

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