[vsnet-alert 9235] V1280 Sco Optical and Near-Infrared Photometry

[Arai Akira]

V1280 Sco Optical and Near-Infrared Photometry

We took optical and near-infrared images of V1280 Sco with the 1.5m KANATA telescope at Higashi-Hiroshima Observatory, Japan.
We obtained V, Rc, Ic, J and Ks-band images.
We estimated the magnitudes of V1280 Sco as

SCOV1280 20070306.85640  10.558V +/-0.003 KANATA
SCOV1280 20070306.86767  9.530Rc +/-0.005 KANATA
SCOV1280 20070306.85951  8.826Ic +/-0.005 KANATA
SCOV1280 20070306.86025  6.571J  +/-0.014 KANATA
SCOV1280 20070306.86493  < 3.8Ks           KANATA

In Ks-band, we can estimate only a lower limit of magnitude because V1280 Sco is too bright and saturated in our images.

We estimated the intrinsic color of V1280 Sco by correcting the galactic extinction using Schlegel et al. 1998ApJ,500,525S.
We got A_V=1.196, A_J=0.325 and A_K=0.132, which yield the intrinsic V-J=3.1 and V-Ks > 5.7.

This result indicates V1280 Sco is currently quite red.
The rapid decline starting a few days ago may be due to the dust formation.

The Optical images were calibrated with a near bright star(R.A.= 254.407371,Dec.=-32.365391)form AAVSO public calibration sequence
"ftp://ftp.aavso.org/public/calib/v1280sco.dat".

The infrared images were calibrated with the same comparison star in the 2MASS catalog.

Regards,
Akira Arai and Makoto Uemura,
Hiroshima University, Japan.