2001A&A...366..945B


Query : 2001A&A...366..945B

2001A&A...366..945B - Astronomy and Astrophysics, volume 366, 945-964 (2001/2-2)

Falling Evaporating Bodies around Herbig stars. A theoretical study.

BEUST H., KARMANN C. and LAGRANGE A.-M.

Abstract (from CDS):

Transient spectral absorption events monitored now for years towards the star β Pictoris have been interpreted as resulting from the transit across the line of sight of evaporating star-grazing kilometer-sized bodies (Falling Evaporating Bodies, or FEBs). Several Herbig Ae/Be stars of various ages have been observed to exhibit somehow similar absorption events that have been attributed to similar FEB events. We investigate here this question from a modeling point of view. Adapting the FEB simulation code we had developed earlier specifically for β Pic to the case of typical Herbig Ae/Be stars, we try to derive in which conditions FEB-like objects may generate detectable transient absorption events. We compare these conditions with those found in the case of β Pic. A major difference with β Pic is that Herbig Ae/Be stars have strong stellar winds (10–9-10–7M/yr). Those winds appear to have a drastic interaction with the gaseous material escaped from the FEBs. With the presence of such stellar winds, the spectral signatures of FEBs are not detectable, unless their mass loss rate is huge. This translates into very large bodies (∼100km size), instead of ∼15km for β Pic FEBs. This appears unrealistic in terms of amount of planetesimal mass needed in the disks surrounding these stars. We discuss then the validity of the FEB hypothesis for specific example stars. It turns out that for the younger (a few 106yr old) Herbig Ae/Be stars like AB Aur, with well identified winds >10–8M/yr, the variable features sometimes observed are not likely to be due to FEBs, unless produced in wind free cavities. For older (>107yr old) stars Herbig Ae/Be like HD 100546, the FEB scenario could still explain the spectral events observed, but either the wind must to be weaker than ∼10–10M/yr (which cannot be excluded so far), or the FEBs approach the star in wind free cavities.

Abstract Copyright:

Journal keyword(s): stars: circumstellar matter - stars: early-type - stars: individual: β Pic - methods: numerical - techniques: spectroscopic

Simbad objects: 8

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Number of rows : 8
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 HD 256 ** 00 07 18.2658367200 -17 23 13.173158760   6.311 6.203 7.36   A3Vn_sh 105 0
2 V* AB Aur Ae* 04 55 45.8458932216 +30 33 04.292077032 7.20 7.16 7.05 6.96 6.70 A0Ve 994 2
3 V* UX Ori Ae* 05 04 29.9878898040 -03 47 14.286732072 10.25 10.93 8.70 9.62 9.43 A4IVe 351 1
4 * bet Pic PM* 05 47 17.0876901 -51 03 59.441135 4.13 4.03 3.86 3.74 3.58 A6V 1785 1
5 HD 42111 * 06 08 57.9037271424 +02 29 58.885200456 5.86 5.80 5.73     B9V 120 0
6 HD 100546 Be* 11 33 25.4408872296 -70 11 41.241297948   6.71 6.30   6.64 A0VaekB8_lB 719 1
7 * c Oph Be* 17 31 24.9541340 -23 57 45.513592 4.75 4.81 4.81 4.74 4.72 A0V 264 0
8 HD 163296 Ae* 17 56 21.2881851168 -21 57 21.871819008 7.00 6.93 6.85 6.86 6.67 A1Vep 956 0

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2022.06.27-19:10:25

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