2021A&A...656A.145K


Query : 2021A&A...656A.145K

2021A&A...656A.145K - Astronomy and Astrophysics, volume 656A, 145-145 (2021/12-1)

YY Hya and its interstellar environment.

KIMESWENGER S., THORSTENSEN J.R., FESEN R.A., DRECHSLER M., STROTTNER X., GERMINIANI M., STEINDL T., PRZYBILLA N., WEIL K.E. and RUPERT J.

Abstract (from CDS):


Context. During a search for previously unknown Galactic emission nebulae, we discovered a faint 36' diameter Hα emission nebula centered around the periodic variable YY Hya. Although this star has been classified as an RR-Lyr variable, such a classification is inconsistent with a Gaia distance of ≃450 pc. The GALEX image data also show YY Hya as having a strong UV excess, suggesting the existence of a hot and compact binary companion.
Aims. We aim to clarify the nature of YY Hya and its nebula.
Methods. In addition to our discovery image data, we obtained a 2.5° x 2.5° image mosaic of the whole region with CHILESCOPE facilities and time-series spectroscopy at MDM observatory. Also, we used data from various space missions to derive an exact orbital period and a spectral energy distribution.
Results. We find that YY Hya is a compact binary system containing a K dwarf star that is strongly irradiated by a hot white dwarf companion. The spectral characteristics of the emission lines that are visible only during the maximum light of the perfectly sinusoidal optical light curve show signatures resembling those of members of the BE UMa variable family. These are post-common-envelope pre-cataclysmic variables. However, the companion star here is more massive than that found in other group members and, thus, the progenitor of the white dwarf must have been a star between 3 and 4 M. The nebula appears to be an ejected common-envelope shell with a mass on the order of one M and an age of 500 000 yr. This makes it the biggest such shell known thus far. The alignment of neighboring nebulosities some 45' to the northeast and southwest of YY Hya suggests that the system has had strong bipolar outflows. We also briefly speculate that it might be related to the 1065 BP "guest-star" reported in ancient Chinese records.

Abstract Copyright: © ESO 2021

Journal keyword(s): novae, cataclysmic variables - white dwarfs - evolution - stars: individual: YY Hya

Simbad objects: 24

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Number of rows : 24
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 GD 2 WD* 00 07 32.2596160176 +33 17 27.605949792 12.321 13.482 13.791 13.940 14.119 DA1.0 95 0
2 V* V723 Cas No* 01 05 05.3607320352 +54 00 40.238720388   15.817 15.484 15.044   ~ 195 0
3 BD+46 442 * 01 45 47.0311634664 +46 49 00.937724124   10.02 9.46     F2III 25 0
4 PG 0231+051 WD* 02 33 41.3574299856 +05 18 43.649856216 14.562 15.776 16.096 16.267 16.639 DAO.6 144 0
5 PN HFG 1 PN 03 03 47.0096763024 +64 54 35.517676320     14.56 13.99   ~ 105 0
6 HD 269696 HS* 05 31 40.3594532592 -69 53 02.153902236 9.74 10.92 11.15     sdB+dM 186 0
7 PN G252.8+19.9 PN 09 26 -22.4           ~ 1 0
8 UCAC4 339-054181 * 09 26 18.5235055352 -22 23 07.711456943   13.962 13.468 13.443   ~ 2 0
9 V* YY Hya RR* 09 26 20.5964861424 -22 23 38.382949032     13.87     ~ 7 0
10 PN G253.7+19.4 PN 09 27 31.460 -23 22 34.40           ~ 1 0
11 * alf Ant PM* 10 27 09.1006393440 -31 04 04.004901300 7.33 5.70 4.25 3.15 2.36 K3III 75 0
12 V* BE UMa CV* 11 57 44.8279856952 +48 56 18.313757772     15.09     DO+M1/5e 125 0
13 EC 11575-1845 HS* 12 00 05.6456553960 -19 02 03.968781864   13.02 13.20 13.51   sdO+dMe 35 1
14 Ton 617 WD* 12 26 30.8730979008 +30 38 52.652529600   16.099 16.05     DA+M3 58 0
15 V* NN Ser CV* 15 52 56.1203524080 +12 54 44.429312196     16.51     DAO1+M4 261 0
16 TYC 2597-735-1 * 16 48 37.4122833696 +35 12 09.441496044   11.71 11.13     ~ 4 0
17 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 13433 0
18 UCAC4 443-085347 CV* 18 52 03.5647256952 -01 28 39.190318140       13.373   ~ 152 0
19 HS 1857+5144 CV* 18 58 32.0885126712 +51 48 57.517565256   15.7   16.3   M5 18 0
20 NAME Ethos 1 PN 19 16 31.4893892688 +36 09 47.679159096           ~ 29 0
21 PN A66 63 PN 19 42 10.2896588688 +17 05 14.458509132           sdO+G: 209 1
22 IRAS 19417+1701 PN 19 43 59.5114618200 +17 09 00.963778248   11.2   10.6   ~ 58 0
23 V* WZ Sge CV* 20 07 36.5037622512 +17 42 14.733254952   15.30 15.20     DAepv 928 0
24 GD 245 CV* 22 58 48.1351624092 +25 15 43.908615894   13.699 13.650 13.833   DA2.2 65 0

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2023.01.31-02:10:50

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