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J/ApJ/831/133   Follow-up of probable young star ASASSN-15qi   (Herczeg+, 2016)

The eruption of the candidate young star ASASSN-15qi. Herczeg G.J., Dong S., Shappee B.J., Chen P., Hillenbrand L.A., Jose J., Kochanek C.S., Prieto J.L., Stanek K.Z., Kaplan K., Holoien T.-S., Mairs S., Johnstone D., Gully-Santiago M., Zhu Z., Smith M.C., Bersier D., Mulders G.D., Filippenko A.V., Ayani K., Brimacombe J., Brown J.S., Connelley M., Harmanen J., Itoh R., Kawabata K.S., Maehara H., Takata K., Yuk H., Zheng W. <Astrophys. J., 831, 133-133 (2016)> =2016ApJ...831..133H (SIMBAD/NED BibCode)
ADC_Keywords: Photometry, UBV ; YSOs Keywords: stars: formation; stars: pre-main sequence; stars: variables: general; stars: winds, outflows Abstract: Outbursts on young stars are usually interpreted as accretion bursts caused by instabilities in the disk or the star-disk connection. However, some protostellar outbursts may not fit into this framework. In this paper, we analyze optical and near-infrared spectra and photometry to characterize the 2015 outburst of the probable young star ASASSN-15qi. The ∼3.5mag brightening in the V band was sudden, with an unresolved rise time of less than one day. The outburst decayed exponentially by 1mag for 6 days and then gradually back to the pre-outburst level after 200 days. The outburst is dominated by emission from ∼10000K gas. An explosive release of energy accelerated matter from the star in all directions, seen in a spectacular cool, spherical wind with a maximum velocity of 1000km/s. The wind and hot gas both disappeared as the outburst faded and the source returned to its quiescent F-star spectrum. Nebulosity near the star brightened with a delay of 10-20 days. Fluorescent excitation of H2 is detected in emission from vibrational levels as high as v=11, also with a possible time delay in flux increase. The mid-infrared spectral energy distribution does not indicate the presence of warm dust emission, though the optical photospheric absorption and CO overtone emission could be related to a gaseous disk. Archival photometry reveals a prior outburst in 1976. Although we speculate about possible causes for this outburst, none of the explanations are compelling. Description: The outburst of ASASSN-15qi (2MASS J22560882+5831040) occurred on JD2457298 (2015 October 2; UTC dates are used herein). The All-Sky Automated Survey for Supernovae (ASAS-SN) is an all-sky V-band transient survey with a limiting magnitude of ∼17. ASAS-SN photometry of ASASSN-15qi was obtained from two different telescopes on Haleakala, Hawaii with intervals of one to three days. ASAS-SN photometry is listed in Table 2. Archival photometry, ground-based optical photometry with Las Cumbres Observatory Global Telescope Network (LCOGT) 1m telescope at McDonald Observatory between 2015 October 23 and December 23 and at the Liverpool Telescope on 2016 April 26 and June 11, Swift/UVOT photometry on 2015 October 12 (ID 00034098001) and 2015 December 27 (ID 00034098002), NIR photometry with the NOTCam camera at the Nordic Optical Telescope (NOT) on 2015 December 22 and Spitzer/IRAC MIR photometry on 2006 December 29 (Program ID 30734, PI Donald Figer) and James Clerk Maxwell Telescope (JCMT) SCUBA2 submillimeter observations of ASASSN-15qi on 2015 November 5 and optical and NIR spectroscopy observations are also described in section 2. Objects: ------------------------------------------------------------------- RA (ICRS) DE Designation(s) ------------------------------------------------------------------- 22 56 08.82 +58 31 04.1 ASASSN-15qi = 2MASS J22560882+5831040 ------------------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 35 99 The ASAS-SN photometry
See also: B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014) II/321 : IPHAS DR2 Source Catalogue (Barentsen+, 2014) I/284 : The USNO-B1.0 Catalog (Monet+ 2003) II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) J/MNRAS/458/3479 : SVM selection of WISE YSO Candidates (Marton+, 2016) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 13 F13.5 d JD Julian Date of the observation 15- 19 F5.2 mag Vmag [13.5/18] V band magnitude 21- 24 F4.2 mag e_Vmag [0.02/0.8] The 1σ error in Vmag 26- 30 F5.2 Jy Flux [0.2/15] V band flux density 32- 35 F4.2 Jy e_Flux [0.1/0.5] The 1σ error in Flux
History: From electronic version of the journal
(End) Prepared by [AAS), Emmanuelle Perret [CDS] 06-Feb-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

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