November 17, 2017
Event: Nova in Vela (ASASSN-17mt) and associated observing campaign
Discovered by: ASAS-SN (K. Z. Stanek (Ohio State University) et al.; ATel #10772)
Discovery magnitude: V=11.3, using data from the quadruple 14-cm "Cassius" telescope at CTIO, Chile
Discovery date: 2017 September 24.39 UT
Coordinates (2000.0): R.A. 08 50 29.62 Decl. -47 45 28.3 (from VSX)
Spectra: Spectroscopy indicating that ASASSN-17mt is a classical nova in the optically thick (Fe-curtain) stage was obtained 2017 September 28.77 UT by P. Luckas (International Centre for Radio Astronomy Research, Univ. of Western Australia; ARAS Group; ATel #10795).
Observing recommendations: Observations of all types (visual, CCD, DSLR, spectroscopy) and multiple bands as instrumentation permits are strongly encouraged as the nova evolves.
K.-L. Li et al. (Michigan State University) report a likely Fermi-LAT detection of ASASSN-17mt (ATel #10977), and have secured weekly observations with Swift for the next ten weeks. Additional multiwavelength observations may also take place. Increased and continuing optical coverage is essential, with V and I bands the highest priority. Visual observations are welcome.
Observations reported to the AAVSO:
2017 Jul. 07.95 UT, <16.9 V (ASAS-SN, ATel #10772);
Sep. 24.39, 11.3 V (ASAS-SN, discovery observation, ATel #10772);
23.40, 11.3: V (ASAS-SN, ATel #10772);
29.30903, <11.1 (PLA, A. Padilla Filho, Rio de Janeiro, Brazil);
Oct. 03.72370, 10.98 B +/-0.04(OCN, S. O'Connor, St. George, Bermuda);
Oct. 03.72530, 9.80 V +/-0.022(O'Connor);
Oct. 03.72660, 9.07 R +/-0.03 (O'Connor);
Oct. 09.77720, 11.20 TB +/-0.04 (O'Connor);
Oct. 09.77850, 9.95 V +/-0.03 (O'Connor);
Oct. 09.77970, 8.81 R +/-0.03 (O'Connor);
Oct. 09.78080, 7.70 I +/-0.05 (O'Connor);
Oct. 11.82710, 10.0 (PEX, A. Pearce, Nedlands, W. Australia);
Oct. 12.76110, 11.15 B +/-0.05 (O'Connor);
Oct. 12.76200, 9.84 V +/-0.05 (O'Connor);
Oct. 12.82500, 10.1 (Pearce);
Oct. 17.72640, 9.12 V +/-0.03 (O'Connor);
Oct. 17.72740, 6.91 I +/-0.02 (O'Connor);
Oct. 19.81880, 10.1 (Pearce);
Oct. 20.83540, 10.0 (Pearce);
Oct. 21.70180, 10.95 B +/-0.04 (O'Connor);
Oct. 21.70260, 9.79 V +/-0.04 (O'Connor);
Oct. 21.70340, 8.15 R +/-0.09 (O'Connor);
Oct. 24.79310, 10.0 (Pearce);
Oct. 29.80350, 10.8 (Pearce);
Nov. 11.80280, 10.1 (Pearce);
Nov. 13.68150, 10.05 V +/-0.01 (O'Connor);
Nov. 13.68190, 8.54 R +/-0.03 (O'Connor);
Nov. 13.79030, 10.1 (Pearce);
Nov. 15.76810, 10.8 (Pearce);
Charts: Finder charts with a comparison star sequence for ASASSN-17mt may be created using the AAVSO Variable Star Plotter (VSP).
Submit observations: Please submit observations to the AAVSO International Database using the name ASASSN-17mt. Once a GCVS name is announced in an IAU Circular or CBET, please use that name.
Notes:
a. Designated ASASSN-17mt in the course of the ASAS-SN survey. Unless otherwise noted and except for observations reported to the AAVSO, the information in this Alert Notice is taken from ATels #10772, #10774, #10785, and #10795, and #10977.
b. Stanek et al. report that there was an ~80-day seasonal gap in the ASAS-SN coverage before the observations given above, so the nova could have peaked already. Nothing is seen down to <16.9 V at the location of the nova in subtracted images taken on UT 2017-07-07.95 and before. They also report that nothing had been detected since ASAS-SN began observing the location in February 2016.
c. Possible progenitor may be 2MASS J08502962-4745283 = WISE J085029.63-474528.0.
d. This nova is being followed on the AAVSO's Time Sensitive Alerts forum (https://www.aavso.org/asassn-17mt-classical-galactic-nova-11-mag-vela) and its Novae forum (https://www.aavso.org/asassn-17mt-nova-vela).
Congratulations to the ASAS-SN team on this discovery!
This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.
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