Skip to main content

Special Notice #250: Possible Type-Ia Supernova in M101

P. Nugent et al. report in ATel #3581 that a possible Type-Ia supernova has been discovered by the Palomar Transient Factory shortly after eruption in the galaxy M101 and has been designated "PTF11kly".  The object is currently at a magnitude of g=17.2, but may well rise by several magnitudes. The object is well placed within M101 for good photometry, and observations of this potential bright SNIa are strongly encouraged.

The (J2000) coordinates reported for the object are

    RA: 14:03:05.81 , Dec: +54:16:25.4

There are currently no comparison stars available in VSP for this field; please indicate clearly the comparison stars that you use for photometry when reporting observations.  Please retain your images and/or photometry for recalibration when comparison star magnitudes are available.

Charts for PTF11kly may be plotted with AAVSO VSP:

You should select the DSS option when plotting, as the galaxy will not appear on standard charts.

This object has been assigned the name "PTF11kly" for use with AAVSO VSP and WebObs; please use this name when reporting observations until it is conclusively classified as a supernova and a proper SN name is assigned.

This Special Notice was prepared by Matthew Templeton.



Information on submitting observations to the AAVSO may be found at:


A Special Notice archive is available at the following URL:

Subscribing and Unsubscribing may be done at the following URL:

AAVSO 49 Bay State Rd. Cambridge, MA 02138 617-354-0484