Joint Astronomy Centre
Show document only
JAC Home
JCMT
About the JAC
Contact Info
OMP
Outreach
Seminars
Staff-only Wiki
Weather
Web Cameras
____________________

See the UKIRT home page for the current status of UKIRT
Survey Observing
Other Observing
Observing Tool Manual
Schedule
Applying For Time
Get UKIDSS Data
Get non-UKIDSS Data
Data Reduction
Acknowledge Us
Telescope
WFCAM
Cassegrain
Technical Reference
JAC Safety Manual
TSS Priority Page
faint standards

Extended Standards List

The 55 stars in the table below, all fainter than K = 9.5, have been observed on an average of 6.1 photometric nights between late 1994 and early 1998. They were observed together with stars from the Fundamental List, which were used to determine extinctions and system zero-points. Fuller details are given after the Table. The results are presented in Hawarden et al. 2001 MNRAS 325, 563.



Number  Other        RA  (J2000) DEC       K     sem    N     J-H    sem    N     H-K    sem    N Inv.     
        Name                                                                                     on TV?


FS 101  fs2-29  00 13 43.58 +30 37 59.9 10.384 (0.006) [ 8]  0.139 (0.004) [ 8]  0.032 (0.003) [ 8]
FS 102  p525-e  00 24 28.50 +07 49 00.1 11.218 (0.005) [ 6]  0.318 (0.005) [ 7]  0.052 (0.002) [ 6]
FS 103  p241-g  00 36 29.60 +37 42 54.3 11.731 (0.006) [ 6]  0.515 (0.003) [ 6]  0.084 (0.006) [ 6]
FS 104  p194-r  01 04 59.43 +41 06 30.8 10.409 (0.005) [ 7]  0.101 (0.004) [ 7]  0.026 (0.002) [ 7]
FS 105  p527-f  01 19 08.19 +07 34 11.5 10.970 (0.004) [ 6]  0.471 (0.008) [ 6]  0.080 (0.001) [ 6]

FS 106  p152-f  01 49 46.94 +48 37 53.2 11.759 (0.005) [ 5]  0.616 (0.005) [ 6]  0.103 (0.006) [ 5]
FS 107  fs2-03* 01 54 10.14 +45 50 38.0 10.231 (0.015) [ 3]  0.213 (0.010) [ 3]  0.050 (0.004) [ 3]
FS 108  fs2-04  03 01 09.85 +46 58 47.7  9.731 (0.004) [ 5]  0.290 (0.004) [ 5]  0.059 (0.003) [ 6]
FS 109  g-129   03 13 24.16 +18 49 38.4 10.807 (0.006) [ 6]  0.464 (0.005) [ 7]  0.161 (0.004) [ 7]
FS 110  p533-d  03 41 02.22 +06 56 15.9 11.324 (0.003) [ 6]  0.308 (0.002) [ 7]  0.078 (0.004) [ 7]

FS 111  fs2-05  03 41 08.55 +33 09 35.5 10.289 (0.006) [ 7]  0.262 (0.006) [ 7]  0.089 (0.002) [ 7]
FS 112  s618-d  03 47 40.70 -15 13 14.4 10.899 (0.005) [ 6]  0.264 (0.004) [ 6]  0.047 (0.005) [ 6]
FS 113  p117-f  04 00 14.07 +53 10 38.5 12.432 (0.005) [ 6]  0.372 (0.003) [ 6]  0.109 (0.005) [ 6]
FS 114  Hy214?  04 19 41.72 +16 45 22.4 13.445 (0.006) [ 5]  0.604 (0.002) [ 6]  0.337 (0.006) [ 5]
FS 115  b216-b5 04 23 18.17 +26 41 16.4 10.171 (0.004) [ 6]  1.585 (0.009) [ 7]  0.772 (0.004) [ 7]*

FS 116  b216-b7 04 23 50.18 +26 40 07.7 10.949 (0.002) [ 7]  1.261 (0.007) [ 6]  0.511 (0.003) [ 7]*?
FS 117  b216-b9 04 23 56.61 +26 36 38.0 10.078 (0.004) [ 7]  0.950 (0.008) [ 7]  0.437 (0.002) [ 7]
FS 118 b216-b13 04 24 33.49 +26 33 37.8 10.446 (0.005) [ 6]  0.723 (0.005) [ 6]  0.266 (0.001) [ 6]
FS 119  fs2-53  05 02 57.44 -01 46 42.6  9.851 (0.004) [ 6]  0.045 (0.006) [ 6]  0.019 (0.002) [ 6]
FS 120  lhs216  06 14 01.44 +15 09 58.3 10.626 (0.006) [ 6]  0.503 (0.004) [ 7]  0.199 (0.006) [ 7]

FS 121  s772-g  06 59 46.82 -04 54 33.2 11.315 (0.003) [ 7]  0.561 (0.003) [ 7]  0.108 (0.003) [ 7]
FS 122  p161-d  07 00 52.02 +48 29 24.0 11.338 (0.003) [ 7]  0.268 (0.003) [ 6]  0.046 (0.003) [ 7]
FS 123  p486-r  08 51 11.88 +11 45 21.5 10.211 (0.004) [10] -0.012 (0.002) [10] -0.022 (0.004) [10]
FS 124  lhs254  08 54 12.07 -08 04 58.9 10.776 (0.004) [ 6]  0.481 (0.006) [ 7]  0.266 (0.005) [ 7]
FS 125  p259-c  09 03 20.60 +34 21 03.9 10.374 (0.005) [10]  0.376 (0.002) [ 9]  0.052 (0.003) [10]

FS 126  p487-f  09 19 18.73 +10 55 54.2 11.680 (0.005) [10]  0.564 (0.003) [10]  0.105 (0.003) [ 9]
FS 127  p212-c  10 06 29.03 +41 01 26.6 11.654 (0.004) [10]  0.261 (0.004) [ 9]  0.040 (0.003) [10]
FS 128 lhs2347  11 05 10.40 +07 06 48.7 12.078 (0.004) [ 5]  0.616 (0.003) [ 5]  0.309 (0.005) [ 6]
FS 129 lhs2397a 11 21 48.95 -13 13 07.9 10.709 (0.006) [ 8]  0.724 (0.006) [ 8]  0.425 (0.002) [ 7]
FS 130  p264-f  11 24 55.92 +34 44 38.5 12.252 (0.003) [ 6]  0.596 (0.006) [ 7]  0.099 (0.004) [ 6]

FS 131  p266-c  12 14 25.40 +35 35 55.6 11.314 (0.005) [ 5]  0.259 (0.003) [ 6]  0.032 (0.004) [ 5]
FS 132  s860-d  12 21 39.36 -00 07 13.3 11.836 (0.004) [ 6]  0.290 (0.003) [ 7]  0.034 (0.005) [ 6]
FS 133  p172-e  13 15 52.80 +46 06 36.9 11.877 (0.004) [ 5]  0.367 (0.005) [ 5]  0.060 (0.003) [ 4]
FS 134  lhs2924 14 28 43.37 +33 10 41.5 10.747 (0.004) [ 6]  0.746 (0.004) [ 6]  0.424 (0.002) [ 6]
FS 135  s867-v  14 40 58.04 -00 27 46.6 11.594 (0.003) [ 5]  0.344 (0.003) [ 5]  0.046 (0.002) [ 6]

FS 136  S868-G  14 59 32.05 -00 06 17.0 11.883 (0.005) [ 6]  0.553 (0.004) [ 6]  0.090 (0.004) [ 6]
FS 137  p565-c  16 26 42.72 +05 52 20.3 11.829 (0.006) [ 5]  0.273 (0.006) [ 7]  0.045 (0.003) [ 6]
FS 138  p275-a  16 28 06.72 +34 58 48.3 10.412 (0.006) [ 7]  0.030 (0.006) [ 6]  0.002 (0.002) [ 7]
FS 139  p137-f  16 33 52.96 +54 28 22.1 12.103 (0.006) [ 7]  0.512 (0.006) [ 7]  0.091 (0.003) [ 7]
FS 140  s587-t  17 13 22.65 -18 53 33.8 10.369 (0.006) [ 5]  0.369 (0.004) [ 5]  0.060 (0.005) [ 5]

FS 141  p389-d  17 48 58.87 +23 17 43.7 10.812 (0.006) [ 7]  0.303 (0.004) [ 7]  0.061 (0.003) [ 7]
FS 142 Ser-EC51*18 29 51.26 +01 13 19.0 13.393 (0.011) [ 2]  1.495 (0.005) [ 2]  0.750 (0.006) [ 2]*
FS 143 Ser-EC68*18 29 53.79 +01 13 29.9 13.018 (0.010) [ 4]  2.336 (0.011) [ 3]  1.200 (0.005) [ 4]*
FS 144 Ser-EC84*18 29 56.90 +01 12 47.1 11.046 (0.001) [ 2]  2.513 (0.017) [ 2]  1.302 (0.010) [ 2]*
FS 145 Ser-EC16018 30 05.81 +01 13 47.3 12.160 (0.006) [ 4]  3.234 (0.049) [ 4]  1.562 (0.009) [ 4]*

FS 146  p280-u  18 54 04.01 +37 07 18.6 10.141 (0.005) [ 5]  0.511 (0.005) [ 5]  0.070 (0.003) [ 5]
FS 147  p230-a  19 01 55.27 +42 29 19.6  9.866 (0.004) [ 4]  0.028 (0.004) [ 5]  0.015 (0.003) [ 5]
FS 148  s810-b  19 41 23.41 -03 50 56.9  9.478 (0.004) [ 5]  0.020 (0.008) [ 5]  0.011 (0.005) [ 5]
FS 149  p338-c  20 00 39.25 +29 58 40.0 10.086 (0.009) [ 6]  0.023 (0.008) [ 6] -0.003 (0.003) [ 6]
FS 150  fs2-22  20 36 08.44 +49 38 23.5  9.960 (0.005) [ 8]  0.154 (0.007) [ 9]  0.044 (0.003) [ 9]

FS 151  p340-h  21 04 14.75 +30 30 21.2 11.876 (0.007) [ 8]  0.274 (0.006) [ 8]  0.061 (0.005) [ 8]
FS 152  p460-e  22 27 16.12 +19 16 59.2 11.057 (0.005) [ 9]  0.521 (0.005) [ 8]  0.062 (0.004) [ 9]
FS 153  s820-e  23 02 32.07 -03 58 53.1 10.896 (0.004) [ 6]  0.580 (0.005) [ 7]  0.105 (0.002) [ 7]
FS 154  s893-d  23 18 10.08 +00 32 55.6 11.064 (0.005) [ 6]  0.264 (0.003) [ 7]  0.042 (0.003) [ 7]
FS 155  fs2-27  23 49 47.82 +34 13 05.1  9.413 (0.006) [ 6]  0.511 (0.003) [ 5]  0.085 (0.003) [ 6]

NB: (1)fs2-29 = CMC 400101, fs2-03 = CMC 600954, fs2-04 = CMC 502032, fs2-05 = CMC 601790, 
       fs2-53 = SAO 131719, fs2-22 = CMC 513807, fs2-27 = CMC 516589
    (2) An asterisk (*) against "other name" indicates an underobserved star (< 4 nights). 

Selection of Stars

Identifying faint stars with good photometric behaviour and of a wide range of colours is not simple. An initial selection of stars was made from the Carlsberg Meridian Catalogue (1989), which lists precise positions and good-quality magnitudes, as well as HD spectral types. These stars are designated ``fs2-nn" in the ``other name" field of the table, to conserve the format, as the CMC designations are long. In the event few CMC stars proved faint enough for this list. Note also that fs2-53 = FS 119 is an SAO, not a CMC, star. In the event the majority of the stars in the Extended List (those designated ``p123-n" or ``s321-m" in ``other name") were selected from the Guide Star Photometric Catalogue (Lasker et al 1988) with a view to reasonably uniform sky coverage and inclusion of a range of colours. Essentially all GSPC stars with B-V > 1.5, which are accessible to UKIRT and sufficiently faint at K, have been included, along with almost all the blue (B-V < 0.3 or so) objects also fulfilling these requirements.

Star numbering

Although all the stars in the Extended List have other designations, they have been assigned new FS numbers (beginning at 101 to distinguish them from the stars of the Fundamental List, which have 2-digit numbers). This is because it has been found that the short and unambiguous numbers assigned to the stars of the Fundamental List assist communications in crowded and noisy telescope control rooms, and users of that list were unanimous in their reluctance to change to longer and more complicated labels in the interests of more correct designation protocol.

Photometric and positional accuracy

Positions have been for the most part redetermined at the telescope and are expected to be accurate to less than an arcsec. All will be thus verified, and proper motions will be provided where significant (especially for the LHS objects, some of which are already several arcsec from where they were observed in 1996-98).

Except for three underobserved objects and the J-H colour of a very red source, the internal standard errors of the mean results are well under 0.01 magnitude (the average is 0.005). Care has been taken to reduce the likelihood of variable stars being included, but given the relative paucity of data on most of these objects, no guarantees are possible. The under-observed objects (<4 nights: FS 107, 142 and 144) are marked in the table with asterisks against their "other name". One star with suspiciously large scatter (FS 114 = Hy 214) is similarly labelled with a question mark.

Transformations between photometric systems

At the time of the observations there were no standard stars with JHK magnitudes on the CIT system of Elias et al., 1982. In fact there were only three ``standard" stars on any other system which were both faint enough to observe with IRCAM3 on UKIRT in normal observing mode and also accessible to the telescope. These are HD 17040, HD 29250 and 100501, in Carter & Meadows, 1995; all are A-F stars, with internal errors about 3 times those of the present objects. The present list therefore includes a number of intrinsically red objects and two sets of heavily reddened sources to facilitate future determinations of colour transformations between this and other photometric systems. The present results, like those for the Fundamental List, are on the IRCAM3 natural system, which is quite close to the CIT system (c.f. Casali & Hawarden, 1992).

The difficulty of transformation between systems on very large telescopes has been somewhat improved since this programme began, with the publication of the ``NICMOS" standards list of Persson et al. (1998) which includes numerous reasonably faint and accessible stars on the Las Campañas Observatory (LCO) system plus transformations to the CIT system based on observations of very red stars (unfortunately all in the Southern Coalsack and inaccessible to UKIRT and Northern VLTs). However Persson et al. include 10 further red stars (J-K > 0.9) which are accessible to UKIRT and faint enough for its imagers in normal mode; one is LHS 2397a = FS 129, above. Two are fainter than K = 11.0 and should be observable with an array instrument in normal readout mode on a 10-m telescope.

Transformation stars in the present list

The red objects in the present list, intended for colour transformations, are drawn from a variety of sources. Nearby red dwarfs with some previous JHK photometry (S.K.Leggett, personal communications 1995,1996) include g-129 (FS 109), Hyades 214 (FS 114: the suspected variable), LHS 216 (FS 120), LHS 254 (FS 124), LHS 2347 (FS 128), LHS 2397a (FS 129) and LHS 2924 (FS 134). Four heavily obscured stars in B216 (selected from Goodman et al., 1992 as likely background objects from their polarisation properties) show little photometric scatter. Attempts to use JHK or IJK photometry to select background objects in Sharpless 106 and Lynds 1641 were unsuccessful: all targets proved to be variable (although their IR spectra appeared normal) or else were too involved in nebulosity for easy measurement in a standardised way. However some sources in the Serpens cloud (from Eiroa & Casali, 1992; labelled Ser-ECnnn in the ``other name" column), though underobserved, appear photometrically well-behaved as far as can be judged.

In all there are 20 objects with J-K > 0.5, of which 14 should be observable on a 10-m telescope, while of the 20, 7 have J-K > 1.0 of which 4 should be thus observable.

Stars invisble in the optical

Note that the very red Ser-EC stars, and two of those in B216, are so faint in the visible that they are difficult or impossible to see with a typical 4-m acquisition TV (this is certainly the case at UKIRT), and it will certainly not generally be possible to guide on these objects when observing them unless the telescope in question has an IR guider. These stars are indicated in the last,``Invis. on TV" column of the Table.

Overlap with other lists

Eight stars in this list are included in the main list of neutral-coloured solar-type stars of Persson et al. 1998. These are FS 102 = p525-e, FS 110 = p533-d, FS 122 = p161-d, FS 127 = p212-c, FS 131 = p266-c, FS 135 = s867-v, FS 137 = p565-c, FS 154 = s893-d. In addition to these, FS 129 is the red object LHS2397a, one of Persson et al.'s list of red sources for transformations. The 8 solar-type objects were selected from the preliminary working lists of Persson et al., (M.J.Rieke, personal communication, Dec 1995) to facilitate linkage of the data sets. Intercomparisons have not yet been explored, but zero-point differences are immediately apparent.

References

Carlsberg Meridian Catalogue La Palma, No. 4, 1989. Copenhagen University Observatory, Royal Greenwich Observatory & Real Instituto y Observatorio de la Armada en San Fernando (Servico Publicaciones Armada).

Carter, B.S. & Meadows, V.S., 1995. MNRAS, 276, 734

Eiroa, C. & Casali, M.M., 1992. A&A, 262, 468

Elias, J.H., Frogel, J.A., Matthews, K. & Neugebauer, G., 1982. AJ, 87, 1029

Goodman, A.A., Jones, T.J., Lada, E.A. & Myers, P.C., 1992. ApJ, 399, 108

Lasker, B.M., Sturch, C.R., Lopez, C., Mallama, A.D., McLaughlin, S.F., Russell, J.F., Wisniewski, W.Z., Gillespie, B.A., Jenkner,H., Siciliano, E.D., Kenny, D., Baumert, J.H., Goldberg,A.M., Henry, G.W., Kemper, E & Siegel, M.J., 1998. Ap.J. Supp, 68, 1.

Persson, S.E., Murphy, D.C., Krzeminiski, W., Roth, M. & Rieke, M.J., 1998. AJ, 116, 2475

Contact: Watson P. Varricatt. Updated: Mon Oct 4 14:36:02 HST 2004

Return to top ^