2006AJ....131.2105H


Query : 2006AJ....131.2105H

2006AJ....131.2105H - Astron. J., 131, 2105-2113 (2006/April-0)

M33's variable A: a hypergiant star more than 35 years in eruption.

HUMPHREYS R.M., JONES T.J., POLOMSKI E., KOPPELMAN M., HELTON A., McQUINN K., GEHRZ R.D., WOODWARD C.E., WAGNER R.M., GORDON K., HINZ J. and WILLNER S.P.

Abstract (from CDS):

Variable A in M33 is a member of a rare class of highly luminous, evolved stars near the upper luminosity boundary that show sudden and dramatic shifts in apparent temperature due to the formation of optically thick winds in high mass loss episodes. Recent optical and infrared spectroscopy and imaging reveal that its ``eruption'', begun in ∼1950, has ended, having lasted ~45 yr. Our current observations show major changes in its wind from a cool, dense envelope to a much warmer state surrounded by low-density gas with rare emission lines of Ca II, [Ca II], and K I. Its spectral energy distribution has unexpectedly changed, especially at the long wavelengths, with a significant decrease in its apparent flux, while the star remains optically obscured. We conclude that much of its radiation is now escaping out of our line of sight. We attribute this to the changing structure and distribution of its circumstellar ejecta, corresponding to the altered state of its wind as the star recovers from a high mass loss event.

Abstract Copyright: ∼

Journal keyword(s): stars: individual (M33 Var A) - Stars: Winds, Outflows - Stars: Supergiants

CDS comments: Variable A in M 33 is [HS53] A

Simbad objects: 10

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Number of rows : 10
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026
#notes
1 M 31 AGN 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 13622 1
2 [HS53] A s*y 01 32 32.8025598888 +30 30 25.003726668 20.1 19.9 19.1 18.6 17.7 F8Ia 55 0
3 M 33 GiG 01 33 50.8965749232 +30 39 36.630403128 6.17 6.27 5.72     ~ 6226 1
4 V* VY CMa s*r 07 22 58.3261352189 -25 46 03.194390594 12.01 10.068 8.691 7.938   M5Iae 1169 0
5 * eta Car s*b 10 45 03.545808 -59 41 03.95124 6.37 7.03 6.48 6.123 4.41 LBV 2543 0
6 IRC +10420 pA* 19 26 48.0979492536 +11 21 16.758531216   13.98 11.66     F8Ia+e 492 0
7 HD 204827 SB* 21 28 57.7592315784 +58 44 23.238427956 8.63 8.74 7.94 7.25 6.76 O9.5IV 372 0
8 HD 212322 * 22 23 43.5009664536 -14 18 40.719828816   10.41 9.10     K0III 5 0
9 V* V509 Cas LP* 23 00 05.1012218544 +56 56 43.350876312 8.01 6.68 5.13 3.96 3.11 G4_0 339 0
10 * rho Cas LP* 23 54 23.0325302520 +57 29 57.774737400 7.00 5.85 4.59 3.63 2.89 G2_0 401 0

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