Access to Astronomical Catalogues

← Click to display the menu
J/AJ/154/72   Coordinates and photometry of stars in Haffner 16  (Davidge, 2017)

Haffner 16 redux: revisiting a young cluster in the outer galaxy. Davidge T.J. <Astron. J., 154, 72-72 (2017)> =2017AJ....154...72D (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Photometry, SDSS Keywords: open clusters and associations: individual: Haffner 16 Abstract: Images and spectra recorded with the Gemini Multi-Object Spectrograph on Gemini South are used to investigate the stellar content of the open cluster Haffner 16. The (i',g'-i') color-magnitude diagram (CMD) constructed from these data extends over 10mag in i', sampling the cluster main sequence (MS) and 5mag of the pre-MS (PMS). The fraction of unresolved equal mass binaries among PMS stars is estimated to be 0.6±0.1. The isochrones do not track the PMS on the CMD, in the sense that the PMS has a shallower slope on the CMD than predicted by the models. Still, a dip in star counts, which is associated with the relaxation of PMS stars onto the MS, is identified near i'=17. The depth and brightness of this feature-as well as the morphology of the cluster MS on the CMD-are matched by models with a slightly sub-solar metallicity that have an age of ∼20Myr and a distance modulus of 12.3±0.2. A light profile of Haffner 16 is constructed in the W1 filter (λcen=3.4µm), which suggests that the cluster is surrounded by a diffuse stellar halo. Spectra of candidate cluster MS and PMS stars selected according to location on the CMD are presented. The spectra show characteristics that are suggestive of a sub-solar metallicity. Hα emission is common among objects on the PMS locus on the CMD near i'=18. It is suggested that the location of the Haffner 16 PMS on the CMD is affected by large-scale cool spot activity, likely induced by rapid stellar rotation. Description: The images and spectra that are the basis of this study were recorded with Gemini Multi-Object Spectrograph (GMOS) on Gemini South as part of program GS-2014A-Q-84 (PI: Davidge). GMOS is the facility visible-light imager and spectrograph. The detector was (the CCDs that make up the GMOS detector have since been replaced) a mosaic of three 2048*4068 EEV CCDs. Each 13.5µm square pixel subtended 0.073arcsec on the sky. The three CCDs covered an area that is larger than that illuminated by the sky so that spectra could be dispersed outside of the sky field. The images and spectra were both recorded with 2*2 pixel binning. The g' (FWHM=0.55) and i' (FWHM=0.45) images of Haffner 16 were recorded on the night of 2013 December 31. The GMOS spectra were recorded during five nights in 2014 March (Mar 19, Mar 27, and Mar 30) and April (Apr 2, and Apr 3). The spectra were dispersed with the R400 grating (λblaze=7640Å, 400lines/mm). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table4.dat 67 117 Spectroscopic targets
See also: III/232 : STELIB: A library of stellar spectra at R∼2000 (Le Borgne+, 2003) Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 4 A4 --- Star Star identification number (1) 5 A1 --- f_Star [ab*] Flag on Star (*=star that have multiple observations; a and b=stars that are in the same slitlet) 7- 15 A9 --- OStar Star identification number in other mask(s) (1) 17- 26 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000) 28- 37 F10.6 deg DEdeg Declination in decimal degrees (J2000) 39- 45 F7.2 pix Xpix [938.8/2619.7] X tixel"cordinate (2) 47- 53 F7.2 pix Ypix [195.7/2211] Y pixel coordinate (2) 55- 60 F6.3 mag i'mag [13.65/19.78]? The i' band magnitude 62- 67 F6.3 mag g'-i' [-0.26/2.61]? The (g'-i') color index
Note (1): The identification number for each target consists of the mask number (1-6), followed by the slit number, defined such that slitlet number 1 for each mask is the closest to the bottom of the science field. Note (2): On the Gemini Multi-Object Spectrograph (GMOS) detector. Each 13.5µm square pixel subtended 0.073 arcsec on the sky.
History: From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 09-Nov-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

catalogue service

© UDS/CNRS

Contact