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Ez a leg=C3=A9rdekesebb:
The =E2=80=98guest star=E2=80=99 of AD 101 has been previously discussed =
by Hsi (1958),
Ho (1962), Stephenson & Clark (1978) and especially Hert- zog (1986).
Unlike most guest stars, it is at high Galactic latitude (44=E2=97=A6), and=
can be
placed with unusual precision in the sky, since it is described as very
close to a star (=E2=80=98the fourth star of Hsien-Yuan=E2=80=99) which all=
students of
ancient records take to be Alpha Lyncis. Hert- zog argues that a compelling
case can be made for BK Lyn, a scant 29 arcmin away from =CE=B1 Lyn. The
modern-day BK Lyn is an extremely unusual star =E2=80=93 the only short-per=
iod
nova-like among the =E2=88=BC1000 known CVs, and now the only nova-like to =
have
clearly morphed into a dwarf nova. Accurate positional coincidence with a
very unusual object constitutes some evidence of physical associa- tion.
The Chinese records describe the star as =E2=80=98small=E2=80=99, which, in=
the context of
other brightness reports in those records, is taken to mean a magnitude
near zero (Hertzog 1986). Superoutbursts of the modern-day dwarf nova reach=
V
=3D 13.9 (allowing for the difference between V and C magnitudes), and
superoutbursts of dwarf novae are pretty good =E2=80=98standard candles=E2=
=80=99 with Mv =3D +4.5
at maximum light (fig. 1 of P11). Allowing an additional 0.2 mag for
absorption on this line of sight, and a reward of =E2=88=BC0.3 mag for the =
likely
low binary inclination,7 we estimate a distance of =E2=88=BC800 pc. If the =
guest
star is actually BK Lyn, then it apparently rose to Mv =3D =E2=88=929.7 (0.=
2, with a
distance modulus m=E2=88=92M =3D 9.5). That is about right for a fast class=
ical nova,
and a CV is exactly what is needed as a classical-nova progenitor. Finally,
we note that BK Lyn has just executed the move which theorists have long
predicted must occur for very old novae: it has settled back into a
dwarf-nova state. These arguments from physics and brightness strengthen
the argument from positional agreement, and we conclude, following Hertzog,
that BK Lyn is likely to be the remnant of Nova Lyn 101.
Hmm, bazi j=C3=B3.
Ksl
--=20
L=C3=A1szl=C3=B3 L. Kiss
Research Professor & Lend=C3=BClet project leader
Konkoly Observatory
Hungarian Academy of Sciences
klaci72@skype
Web: http://www.konkoly.hu/staff/kiss
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Ez a leg=C3=A9rdekesebb:
=09
=09
=09
The =E2=80=98guest=
star=E2=80=99 of AD=
101 has been previo=
usly discussed by Hsi
(1958), Ho (1962), Stephenson & Clark (1978) and especially Hert-
zog (1986). Unlike most guest stars, it is at high Galactic latitude
(44
>=E2=97=A6), and can=
be placed with unusual precision in the sky, since it
is described as very close to a star (=E2=80=98the fourth star of Hsien-Yua=
n=E2=80=99)
which all students of ancient records take to be Alpha Lyncis. Hert-
zog argues that a compelling case can be made for BK Lyn, a
scant 29 arcmin away from
TMI">=CE=B1 Lyn. The=
modern-day BK Lyn is
an extremely unusual star =E2=80=93 the only short-period nova-like among
the =E2=88=BC<=
span style=3D"font-size:9pt;font-family:Times">1000 known CVs, and now the =
only nova-like to have clearly
morphed into a dwarf nova. Accurate positional coincidence with a
very unusual object constitutes some evidence of physical associa-
tion.
The Chinese record=
s describe the star as =E2=80=98small=E2=80=99, which, in the
context of other brightness reports in those records, is taken to
mean a magnitude near zero (Hertzog 1986). Superoutbursts of the
modern-day dwarf nova reach
:Times;font-style:italic">V
:MTSY">=3D 13.9 (all=
owing for the difference
between
alic">V and <=
span style=3D"font-size:9pt;font-family:Times;font-style:italic">C <=
span style=3D"font-size:9pt;font-family:Times">magnitudes), and superoutbur=
sts of dwarf novae
are pretty good =E2=80=98standard candles=E2=80=99 with
=3D"font-size:9pt;font-family:Times;font-style:italic">M
=3D"font-size:6pt;font-family:Times;vertical-align:-1pt">v
le=3D"font-size:9pt;font-family:MTSY">=3D +
9pt;font-family:Times">4.5 at maximum
light (fig. 1 of P11). Allowing an additional 0.2 mag for absorption
on this line of sight, and a reward of
font-family:MTSY">=E2=88=BC
Times">0.3 mag for the likely low
binary inclination,
rtical-align:3pt">7 =
we estimate a distance of
TSY">=E2=88=BC800 pc=
. If the guest
star is actually BK Lyn, then it apparently rose to
ont-size:9pt;font-family:Times;font-style:italic">M
nt-size:6pt;font-family:Times;vertical-align:-1pt">v
font-size:9pt;font-family:MTSY">=3D =E2=88=92
e:9pt;font-family:Times">9.7
(0.2, with a distance modulus m
ily:MTSY">=E2=88=92M=
=3D
le=3D"font-size:9pt;font-family:Times">9.5). That is about right
for a fast classical nova, and a CV is exactly what is needed as
a classical-nova progenitor. Finally, we note that BK Lyn has just
executed the move which theorists have long predicted must occur
for very old novae: it has settled back into a dwarf-nova state. These
arguments from physics and brightness strengthen the argument
from positional agreement, and we conclude, following Hertzog,
that BK Lyn is likely to be the remnant of Nova Lyn 101.=C2=A0
style>Hmm, bazi j=C3=B3.
span>
n>
Ksl
--
se:collapse;color:rgb(136,136,136);font-family:arial,sans-serif;font-size:1=
3px">L=C3=A1szl=C3=B3 L. KissResearch Professor &=C2=A0
=3D"background-color:rgb(255,255,204);color:rgb(34,34,34)">Lend=C3=BClet
pan>=C2=A0project=C2=A0
or:rgb(34,34,34)">leader
Konkoly Observatory
Hungarian Academy of Sciences
klaci72@skype
We=
b:=C2=A0
85,204)" target=3D"_blank">http://www.konkoly.hu/staff/kiss
<=
/div>
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